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Review

Recent Progress in Photocatalytic Degradation of Water Pollution by Bismuth Tungstate

by
Yingjie Zhang
1,2,
Huijuan Yu
1,
Ruiqi Zhai
1,
Jing Zhang
1,
Cuiping Gao
1,
Kezhen Qi
3,*,
Li Yang
4 and
Qiang Ma
5,*
1
College of Agriculture and Biological Science, Dali University, Dali 671000, China
2
Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali 671000, China
3
College of Pharmacy, Dali University, Dali 671000, China
4
College of International Education, Dali University, Dali 671000, China
5
School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
*
Authors to whom correspondence should be addressed.
Molecules 2023, 28(24), 8011; https://doi.org/10.3390/molecules28248011
Submission received: 16 November 2023 / Revised: 6 December 2023 / Accepted: 7 December 2023 / Published: 8 December 2023
(This article belongs to the Special Issue Recent Advances in Transition Metal Catalysis)
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Abstract

:
Photocatalysis has emerged as a highly promising, green, and efficient technology for degrading pollutants in wastewater. Among the various photocatalysts, Bismuth tungstate (Bi2WO6) has gained significant attention in the research community due to its potential in environmental remediation and photocatalytic energy conversion. However, the limited light absorption ability and rapid recombination of photogenerated carriers hinder the further improvement of Bi2WO6’s photocatalytic performance. This review aims to present recent advancements in the development of Bi2WO6-based photocatalysts. It delves into the photocatalytic mechanism of Bi2WO6 and summarizes the achieved photocatalytic characteristics by controlling its morphology, employing metal and non-metal doping, constructing semiconductor heterojunctions, and implementing defective engineering. Additionally, this review explores the practical applications of these modified Bi2WO6 photocatalysts in wastewater purification. Furthermore, this review addresses existing challenges and suggests prospects for the development of efficient Bi2WO6 photocatalysts. It is hoped that this comprehensive review will serve as a valuable reference and guide for researchers seeking to advance the field of Bi2WO6 photocatalysis.

1. Introduction

With the rapid growth of the global economy and population, water pollution has become an increasingly serious challenge. Solving water pollution problems through the effective utilization of natural resources for economic sustainable development has become the focus of scientific researchers [1,2,3]. The main source of water pollution is the discharge of domestic, agricultural, and industrial sewage [4]. This sewage contains a large amount of heavy metal and organic pollutants. Heavy metals like Hg and Cr are toxic and not easily broken down by the environment, which negatively impact the living environment of aquatic animals and plants [5]. Furthermore, heavy metals can accumulate in the food chain, affecting the growth and development of organisms in the water and leading to stagnation or even death [6]. Common organic pollutants found in sewage include phenolic compounds, aniline compounds, and organophosphorus pesticides. Organic pollutants pose serious hazards to the environment and organisms, lead to contamination of water bodies and soil, exerting toxic effects on plants and animals in the ecosystem, thus disrupting the ecological balance. They may also contaminate agricultural irrigation water, adversely affecting crop growth. Furthermore, certain organic pollutants have the potential to accumulate within organisms and gradually concentrate through the food chain, posing hazards to higher level animals in the food web [7].
The degradation of pollutants in sewage has garnered significant attention from researchers, prompting the exploration of various treatment methods, including flocculation precipitation [8], adsorption [9,10,11], and biological approaches [12]. While these methods have shown effectiveness, they are not without limitations. Flocculation precipitation methods suffer from relatively poor treatment efficacy for specific pollutants and the generation of substantial sludge, leading to high treatment costs. Adsorption methods face constraints due to the adsorbent’s saturation capacity and regeneration difficulties, with certain pollutants proving less amenable to adsorption. Biological methods may experience influence from environmental factors such as temperature and pH, resulting in slower treatment rates. In contrast, semiconductor photocatalysis offers a direct route to oxidize and degrade pollutants via generating photoinduced electrons and holes, hence exhibiting a high degradation efficiency [13,14,15]. Moreover, photocatalysts can optimize their performance through surface modification and carrier design, functioning within the visible light range, thus broadening the scope of photocatalytic applications and imparting this technology with enhanced potential and advantages compared to traditional methods.
The origins of photocatalysis can be traced back to 1972 when Fujishima et al. reported that TiO2 can decompose water into O2 and H2 under ultraviolet (UV) irradiation [16]. This discovery has since garnered significant attention from scientists. Semiconductor photocatalysis has subsequently achieved significant breakthroughs in the fields of environment and energy. Photocatalysts are widely used in water treatment due to their high photocatalytic activity, cleanliness, lack of pollution, and stability [17]. However, many photocatalysts, such as TiO2 and ZnO, only exhibit activity under UV irradiation due to their wide band gaps [18,19,20,21,22]. This limitation in the light response range severely hampers the utilization of sunlight. To maximize the utilization of solar energy, researchers have developed numerous photocatalysts with visible light activity [23].
Many bismuth-based materials have a narrow band gap due to the hybridization of Bi 6s and O 2p orbitals at the valence band (VB) maximum. This property makes them suitable as visible light responsive photocatalysts [24,25,26]. One such material, Bi2WO6, which belongs to the Aurivillius phase family, has garnered considerable attention due to its unique layered structure, favorable visible light photocatalytic activities, high thermal and photochemical stabilities, and environmental friendliness [27,28]. It has also been used in water pollution treatment to remove various pollutants [29,30]. To date, Bi2WO6 has been synthesized using various methods, such as the sol-gel, co-precipitation, molten salt, solvothermal, and hydrothermal processes [31,32,33]. These different synthetic methods have led to the study of numerous Bi2WO6-based photocatalytic materials with distinct properties in environmental, energy, and biological fields [34,35,36,37,38,39]. However, standalone Bi2WO6 as a photocatalyst has certain limitations, including rapid recombination of photogenerated electrons and holes, as well as poor photocatalytic activity. To overcome these shortcomings, several modification strategies have been proposed, including element doping [40], metal deposition [41], and heterojunction construction [42]. These modifications enhance the photocatalytic performance of Bi2WO6 and enable its application in degrading various pollutants such as dyes, antibiotics, and bacteria [43,44,45]. Despite the progress in modifying Bi2WO6 for photocatalytic applications, a detailed review of its modification strategies, specifically for water treatment purposes, has not been conducted. Importantly, research on Bi2WO6 in this area is growing rapidly (Figure 1). Reviewing the water pollution treatment applications of Bi2WO6 based on different modification strategies is necessary to foster further advancements in the field.
This review starts by introducing the structure and property characteristics of Bi2WO6. We then shift our focus to reviewing different modification strategies that have been used to enhance the photocatalytic performance of Bi2WO6. These strategies encompass morphology control, metal and non-metal doping, semiconductor heterojunction, and defective engineering. Furthermore, this review explores recent advancements in water pollution treatment and related applications, as well as delving into the photocatalytic mechanism of Bi2WO6-based photocatalysts. Additionally, we discuss the current challenges and propose potential research directions for future Bi2WO6-based photocatalysts.

2. Structure, Property Characteristics, and Photocatalytic Fundamentals of Bi2WO6

2.1. Structure and Property Characteristics

Bi2WO6 is a relatively straightforward Aurivillius oxide, featuring an orthorhombic structure that consists of corner-shared [WO4]2− layers connected to [Bi2O2]2+ layers [46]. Figure 2a displays the structure of Bi2WO6, where the interleaved layers create an internal electric field that enables the efficient separation of photogenerated electrons and holes [47]. It is well known that the conduction band (CB) of Bi2WO6 is composed of W 5d orbitals, while the valence band (VB) is predominantly made up of the hybrid orbitals of Bi 6s and O 2p [48]. With a band gap of approximately 2.7 eV, Bi2WO6 is a visible light responsive photocatalyst [49,50]. Figure 2b provides insight into some thermodynamic data associated with the photocatalytic reaction process. Remarkably, Bi2WO6 exhibits a positive VB, indicating its significant capability to degrade a broad range of pollutants [51].

2.2. Fundamentals of Photocatalysis

Figure 3 illustrates the photocatalytic reaction mechanisms of Bi2WO6 catalysts [52].
The mechanisms can be summarized as follows: Pollutants are adsorbed on the catalyst surface. When the catalyst absorbs photon energy higher than the band gap energy, photoinduced electrons move from the valence band (VB) to the conduction band (CB), creating holes in the VB. The electrons (e−) and holes (h+) generated migrate to the catalyst’s surface. However, only a small portion (less than 10%) of the generated carriers is available for the photocatalytic reaction, with approximately 90% of them recombining. The catalyst-captured energy activates groups such as superoxide radicals (·O2−) and hydroxyl radicals (·OH), utilizing the generated electrons and holes from the photocatalyst. These radicals are responsible for the degradation of pollutants. Moreover, the electrons and holes themselves can directly degrade pollutants. The degraded products are released from the catalyst’s surface, allowing the photocatalytic reaction to continue. By facilitating the degradation of pollutants and enabling the continuation of the photocatalytic reaction, the Bi2WO6 catalysts play a crucial role in the process.
The photocatalytic efficiency of materials is influenced by several critical factors. These factors include the light absorption ability of the photocatalysts, which is determined by the bandgap of the semiconductor [53], and the separation and transfer efficiencies of the photogenerated electron-hole pairs. High carrier recombination rates result in low photocatalytic efficiency [54]. Furthermore, the external photocatalytic reaction conditions significantly impact the photocatalytic efficiency of the photocatalysts. Factors such as the pH value of the solution, photocatalyst dosage, reaction time, and initial concentrations of pollutants all play vital roles. In a photocatalysis experiment, the pH of the solution can influence the chemical forms of pollutants present in water. Many pollutants exist in different ionic states under varying pH conditions, impacting their reactivity, solubility, and interaction with photocatalysts. Modifying the solution’s pH can alter the charge state of pollutants, thereby affecting their solubility and adsorption properties in water, consequently influencing the progression of the photocatalytic reaction. Moreover, pH variations can also affect the dispersion stability of particles in the solution, consequently impacting the particles’ zeta potential. Unstable dispersion may result in particle aggregation, reducing the effective surface area of the photocatalyst and potentially compromising the efficiency of the photocatalytic reaction. Therefore, achieving efficient photocatalytic reactions requires the use of appropriate photocatalysts and the establishment of suitable reaction conditions.
However, the Bi2WO6 catalyst faces several challenges as a photocatalyst. Firstly, it can only absorb visible light with wavelengths below 450 nm, which is due to its band gap limitation. This restriction hinders its potential for efficiently utilizing the entire visible light spectrum. Secondly, the recombination rate of the photogenerated electron-hole pairs in the Bi2WO6 catalyst remains high, resulting in a decrease in overall photocatalytic efficiency. Additionally, the Bi2WO6 catalyst lacks a sufficient number of surface active sites, which limits its capacity for carrying out photocatalytic reactions. Therefore, it is crucial to optimize these properties of the Bi2WO6 catalyst in order to enhance its photocatalytic activity. This can be achieved through various modification methods, including morphology control, metal and non-metal doping, and the formation of semiconductor heterojunctions [55,56].

3. Morphology Control

The performance of photocatalytic materials depends not only on their chemical composition, but also on their size and shape. In the case of the Bi2WO6 catalyst, its morphology is influenced by the method of synthesis used, such as precipitation, hydrothermal, or solvothermal methods, which are commonly employed in its preparation. These methods often result in irregularly shaped Bi2WO6 particles. It is advantageous to have a high specific surface area with numerous active sites, as this enhances the catalyst’s ability to adsorb reactants. The crystal structure and morphology of Bi2WO6 can be controlled by adjusting synthesis conditions and incorporating surfactants. These factors, in turn, affect its specific surface area, light absorption performance, and efficiency in separating photogenerated carriers. The morphology of the Bi2WO6 catalyst generally falls into four categories: three-dimensional (flower-like), two-dimensional (nanoplates), one-dimensional (nanofiber), and zero-dimensional (nanoparticles). These categories are summarized in Table 1. For example, in Figure 4, Guo et al. [57] and Zheng et al. [58] achieved knob-like and rose-like morphologies of Bi2WO6 photocatalytic materials using the hydrothermal method. Wang et al. [59] obtained a Bi2WO6 photocatalytic material consisting of nanosheets with a large specific surface area through hydrothermal synthesis. Zhou et al. [60] prepared Bi2WO6 powder using the solid phase method, and investigated the impact of different reaction temperatures on its activity. When the preparation temperatures were 300 °C, 350 °C, and 400 °C, the adsorption rates of the samples for Rhodamine B (RhB) solution were 31%, 22%, and 10%, respectively. The gradual decrease in adsorption can be attributed to the gradual increase in particle size and reduction in specific surface area of the powder. As the semiconductor photocatalytic reaction primarily occurs on the surface of the photocatalyst powder, a larger specific surface area is advantageous for increased RhB adsorption, thereby promoting photocatalytic degradation. At a preparation temperature of 400 °C, the resulting powder exhibited significantly increased grain size, leading to reduced photocatalytic activity, with a RhB photodegradation rate of only 47%. On the other hand, at 300 °C, despite the highest adsorption rate of RhB by the obtained powder, its photocatalytic activity was lower than that of the powder obtained at 350 °C. This may be due to the better crystallinity of the powder obtained at 350 °C. Increased semiconductor crystallinity can reduce crystal defects, which are often the recombination centers for photogenerated electrons and holes. Overall, the tungsten bismuth oxide powder obtained at 350 °C demonstrated the strongest visible light photocatalytic activity, achieving a RhB photodegradation rate of 98% after visible light irradiation for 120 min. Mei et al. [61] synthesized nanoplate Bi2WO6 catalysts via the hydrothermal method. With increased hydrothermal synthesis time, the thickness of the nanoplates decreased and their crystallinity became more stable. When the pH is low (pH < 8), BWO-8/BWO-T-10 nanoplates exhibited the highest photocatalytic activity. After two hours of light exposure, the degradation efficiency of tetracycline reached 85%, with a reaction rate of 0.0135 min−1. The material remained highly stable even after three cycles of repeated use. The catalytic mechanism analysis is depicted in Figure 5.

4. Metal Doping

Metal doping refers to the process of introducing metal elements into a photocatalyst to enhance its properties. In the synthesis of the Bi2WO6 catalyst, metals can be added to the reaction system. Metal doping can change the band structure of a semiconductor by introducing additional energy levels or adjusting the lattice structure. This alteration can impact the optoelectronic properties of the semiconductor, such as changes in absorption spectra and the lifetime of photogenerated carriers, thereby influencing its photocatalytic activity [68]. It can also improve the capacity of the photocatalyst to degrade organic pollutants. Additionally, certain metal ions can induce the formation of surface defects, such as oxygen vacancies, through charge compensation mechanisms resulting from the difference in valence between the dopant and the parent cation. It is important to carry out metal doping in a reasonable manner according to the specific requirements of each application. For example, Zhu et al. [69] prepared a Sn-doped Bi2WO6 catalyst, which showed a larger specific surface area and more active sites. The degradation rate of methylene blue increased by 11.4%, and the degradation rate of methylene blue reached 92% when the doping rate of Sn was 2%. Bunluesak et al. [70] constructed an Ag-doped Bi2WO6 catalyst and studied its degradation efficiency on RhB. The incorporation of silver ions can effectively enhance the interfacial charge diffusion and photocatalytic activity of nanoplates. The results showed that the degradation efficiency of pure Bi2WO6 and 10%Ag/Bi2WO6 on RhB were 47.79% and 94.21% under the visible light irradiation, respectively. Gao et al. [71] prepared a Cu-doped Bi2WO6 photocatalyst using a hydrothermal method. The Cu-Bi2WO6 displayed a three-dimensional flower spherical structure with a large specific surface area (85 m2/g), and exhibiting high photocatalytic activity. When the pH was 6 and the Cu load was 0.5 wt.%, the degradation efficiency of phenol by the composite was as high as 92%, 23% higher than Bi2WO6. Zhu et al. [72] also constructed Mg2+, Fe3+, Zn2+, and Cu2+ doped Bi2WO6 catalysts, which exhibited excellent photodegradation performances for antibiotics. Among these catalysts, the Mg2+ doped Bi2WO6 catalyst showed the highest degradation rates of 89.44 and 99.11% for norfloxacin (NOR) and ciprofloxacin (CIP), respectively. And the specific surface area of Mg/Bi2WO6 was 1.6 times higher than Bi2WO6. Other metals can also be added to the Bi2WO6 photocatalysts as shown in Table 2. Metal doping can significantly affect the photocatalytic activity of Bi2WO6, altering its performance in photodegradation processes.

5. Non-Metal Doping

The distribution of metal ions on the surface of metal-doped photocatalysts can be uneven, leading to aggregation or dispersion, which affects the material’s overall performance. Non-metals generally have high ionization energy and electronegativity. When incorporated as dopants, non-metal elements primarily impact the electronic structure and redox properties of the Bi2WO6 catalyst. Non-metals can alter the band structure in the Bi2WO6 catalyst by changing the electron affinities and ionization energies [83]. Additionally, non-metal doping allows for high control precision, accurate concentration, and distribution, making it suitable for modifying Bi2WO6 photocatalysts and enhancing photocatalytic efficiency [84]. For instance, Li et al. [85] prepared flower-like bismuth tungstate using a hydrothermal method with carbon as the carrier. The modified bismuth tungstate catalyst exhibited an excellent photocatalytic performance, with degradation rates of RhB and tetracycline reaching 98% and 87%, respectively. This is attributed to the fact that Bi2WO6/C (2.35 eV) has a narrower band gap than Bi2WO6 (2.64 eV), and the large-area flower-like Bi2WO6. Zhang et al. [86] synthesized I-doped Bi2WO6 photocatalysts through a hydrothermal method, and the amount of iodine doping influenced the photocatalytic activity of the catalysts. The study revealed that 1.0 wt.% iodine-doped Bi2WO6 showed the best removal effect on Hg under visible light irradiation, achieving 97.5% efficiency. The mercury-removal efficiency of Bi2WO6 was 9.1%. This is attributed to the reduction in the potential energy of the conduction band and the decrease in electron-hole pair recombination rate. To enhance the photocatalytic activity of the catalysts, Zheng et al. [87] precipitated silicon carbide, which has a high electron transfer rate, onto bismuth tungstate using a hydrothermal method. This yielded a RhB degradation rate 3.7 times higher than pure bismuth tungstate. Zhu et al. [88] employed a simple hydrothermal method to modify bismuth tungstate with S. The addition of S can effectively change the morphology of bismuth tungstate, resulting in a rose-shaped S/Bi2WO6 composite material, with a Rhodamine B degradation rate of 96.2%. Non-metal doping can influence the morphology, band gap width, and electron-hole recombination rate of bismuth tungstate, thereby enhancing its photocatalytic performance (see Table 3).

6. Semiconductor Heterojunction

A heterojunction is constructed by combining different materials and adjusting their band gap, electrical conductivity, and optical properties. For example, using bismuth tungstate and other semiconductors can effectively change the electronic structure and separate photogenerated charges. Semiconductor heterojunction photocatalysts consist of two or more semiconductors with different energy band structures connected by tightly bound interfaces. Traditionally, there are three types of semiconductor heterojunctions: type I, type II, and type III (see Figure 6). Type I heterojunctions have a nested band structure where the conduction band (CB) position of semiconductor A is higher than that of semiconductor B, but its valence band (VB) level is lower. Unfortunately, this structure causes photogenerated electrons and holes to migrate and aggregate to the semiconductor with the smaller band gap, reducing the redox potential of the photocatalyst and hindering charge separation. Type II heterojunctions, on the other hand, have an ecotone structure in which the CB and one of the semiconductors have higher VB levels than the other. This difference means that the electrons and holes move in opposite directions, allowing for spatial separation and efficient charge separation. Type III heterojunctions have disjointed band structures that prevent carriers from moving between semiconductors, making efficient charge separation impossible. Most research on traditional heterojunctions has focused on type II junctions [93,94].
The semiconductor p-n junction is a special heterostructure composed of p-type and n-type semiconductors that allows for efficient charge separation [95,96]. Kong et al. [97] synthesized a novel 2D Bi2WO6/BiOI catalyst with a p-n junction and surface oxygen vacancies. The mechanism of this p-n junction is depicted in Figure 7. The Fermi level (Ef) of Bi2WO6 (n-type semiconductor) is higher than that of BiOI (p-type semiconductor). Consequently, when they come into contact, electrons diffuse from Bi2WO6 to BiOI, while holes diffuse from BiOI to Bi2WO6. This results in a lowering of the energy band of Bi2WO6 and an upward shift of BiOI’s Ef, until the system reaches an equilibrium, resulting in the formation of an interfacial electric field from Bi2WO6 to BiOI. Under visible light irradiation, photogenic electrons and holes are generated in Bi2WO6 and BiOI. Thanks to the internal electric field, holes in Bi2WO6 quickly transfer to BiOI, while the electron transfer path is reversed. Ultimately, the p-n heterostructure enables ultra-fast directional migration and spatial separation of photogenerated carriers. Furthermore, there exists a multitude of semiconductor heterojunction photocatalysts such as p-n junction Bi-OI/Bi2WO6 [98], Co3O4/Bi2WO6 [99], CoO/Bi2WO6 [100], Bi2WO6/CuS [101], and CuA-lO2/Bi2WO6 [102] that have been utilized for the degradation of environmental pollutants. Mao et al. [101] successfully prepared a Bi2WO6/CuS photocatalyst through the hot solvent method, which exhibited outstanding degradation rates of 99.9%, 74.7%, and 75.7% for single Rhodamine B, tetracycline, and Cr (VI) solutions, respectively. In mixed solutions, the degradation rates of Rhodamine B, tetracycline, and Cr (VI) were 97.7%, 87.6%, and 95.1%, respectively. Moreover, when multiple wastewaters co-exist, p-n heterojunctions in Bi2WO6/CuS shorten the electron transport path, effectively separating and transferring photoelectrons and holes, thereby improving the removal efficiency of both pollutants. In another study by Xie et al. [103], a layered MoSe2/Bi2WO6 composite photocatalyst was prepared using the ultrasonic method. MoSe2/Bi2WO6 showed high catalytic activity under visible light irradiation for 3 h, achieving a degradation rate of p-toluene of nearly 80%. This was attributed to the formation of a p-n heterojunction between materials, which can inhibit the recombination of electron-hole pairs, increase the content of superoxide and hydroxyl free radicals on the surface, and enhance the photocatalytic process.
Traditional type II semiconductor heterojunctions can improve the separation efficiency of photogenerated carriers. However, the directional migration of photogenerated electrons to the corrected CB and holes to more negative VB can reduce the redox potential of the original photogenerated electrons and holes. Additionally, repulsive forces arise between identical charges, which effectively inhibit the electrons and holes to migrate and accumulate. In order to address these challenges, Z-schemes like plant photosynthesis have gained significant attention. As shown in Figure 8, the development history of Z-scheme photocatalysts can be divided into three generations: the liquid-phase Z-scheme, the all-solid-state Z-scheme, and the direct Z-scheme junctions [104]. Furthermore, heterojunctions such as S-type heterojunctions can also be formed between Bi2WO6 and other semiconductor substances. Table 4 lists some of the typical Z-scheme and S-scheme junctions.

7. Defect Engineering

Defect engineering is a promising technique to improve the photocatalytic performance of Bi2WO6 photocatalysts by modifying their crystal defects. Crystal defects are crucial in altering the properties of the photocatalytic materials. These defects refer to the disruption of the periodic arrangement of atoms or molecules in the crystal material and are present in all photocatalysts, thus affecting their photocatalytic behavior. Crystal defects can be classified based on their size into zero-dimensional point defects, such as vacancies, one-dimensional line defects, such as edge dislocations, two-dimensional planar defects, such as grain boundaries, and three-dimensional bulk defects, such as disordered regions [117]. Crystal defects can also be categorized into point defects, line defects, surface defects, and block defects based on their respective positions. Recently, the focus of defect engineering in Bi2WO6 photocatalysts has been on vacancy defects. Gao et al. [118] prepared Bi2WO6 ultrathin nanosheets with an abundance of oxygen vacancies. The presence of oxygen vacancies in the Bi2WO6 structure was confirmed through electron paramagnetic resonance spectroscopy (Figure 9a). The presence of vacancy defects in Bi2WO6 photocatalysts has a significant impact on their photocatalytic activity and performance. Density functional theory indicates that Bi2WO6 with an abundance of oxygen vacancies has a higher adsorption energy, resulting in a stronger capacity to attract and adsorb oxygen molecules (Figure 9b). This suggests that oxygen vacancies enhance the material’s ability to capture oxygen. Additionally, Hang et al. [119] developed Bi2WO6 photocatalysts with both tungsten (W) and oxygen (O) vacancies. The introduction of these vacancies causes a decrease in the valence band (VB) potential, promoting the generation of highly oxidizing holes. Furthermore, these vacancies trap charges and facilitate the separation of electron-hole pairs, ultimately enhancing the photocatalytic performance. Overall, this study highlights the role of vacancies in optimizing the photocatalytic performance of Bi2WO6.

8. Bi2WO6 Photoelectrochemistry

Photoelectrochemistry (PEC) mainly consists of two processes: photoelectroconversion and electrochemistry. Photoelectroconversion refers to the electron transition in light-active materials upon photon absorption, leading to the generation of photoinduced charges, followed by charge separation and transfer, resulting in the formation of photovoltage and the conversion of light energy into electrical energy [120].The electrochemical process involves the partial separation of charges transferring to the electrode/solution interface, where oxidation-reduction reactions occur, generating electrical signals and converting chemical energy into electrical energy. In the photoelectrochemical process, light-active materials serve as the basis of the reaction. Typically, these materials transfer electrons from the conduction band to the electrode, while the holes in the valence band undergo oxidation reactions with electron donors in the solution [121]. Wang et al. [122] reported a hybrid of Bi2WO6 wrapped with reduced graphene oxide (Bi2WO6@rGO) as a photoelectrode for enhanced photocatalytic degradation of organic pollutants. The Bi2WO6@rGO hybrid exhibited a 43.0% and 65.6% increase in the photocatalytic degradation efficiency of Rhodamine B compared to the photocatalytic and electrocatalytic processes, respectively. The enhancement in the photoelectrocatalytic degradation of RhB in the Bi2WO6@rGO hybrid is attributed to a negative shift of 0.26 V in the flat band potential and the spatial separation of photogenerated electrons and holes by external potentials. Pedanekar et al. [123] successfully deposited Bi2WO6 thin films using a simple spray pyrolysis technique. The film deposited with a 70 mL spraying solution quantity exhibited a higher photocurrent density (460 mA/cm2), and the same film, with a large area (10 × 10 cm2), was used for the photocatalytic and photoelectrocatalytic degradation of Rhodamine B dye under solar radiation. The photoelectrocatalytic removal of RhB exhibited a higher degradation efficiency (94%) compared to the photocatalytic process (23%).

9. Conclusions and Outlook

In this review, we provide a comprehensive summary of the recent progress made in the field of water treatment using Bi2WO6-based photocatalysts. We begin by briefly outlining the basic properties and photocatalytic fundamentals of Bi2WO6 photocatalysts. Next, we delve into a detailed discussion of various strategies employed to regulate the performance of Bi2WO6 photocatalysts, including morphology control, metal and non-metal doping, semiconductor heterojunction, and defective engineering. Through the implementation of these strategies, we are able to greatly enhance the light absorption capabilities and separation efficiency of photogenerated electrons and holes. Additionally, we can regulate the surface properties of Bi2WO6, effectively bolstering the overall photocatalytic performance of these materials. The modified Bi2WO6 photocatalysts showcased remarkable degradation efficiencies for organic dyes, antibiotics, and bacteria in aqueous environments. In conclusion, achieving efficient Bi2WO6-based photocatalysts requires several key factors to be carefully considered. Firstly, controlling the hydrothermal synthesis conditions, such as adjusting the pH value and reaction temperature of the precursor solution, can significantly affect the morphology and performance of the catalyst. Secondly, choosing a suitable dopant can alter the band structure, extend the photo response range of the catalyst, and improve its overall performance. Thirdly, leveraging the local surface plasmon resonance effect by loading appropriate metals onto the catalyst surface promotes effective charge separation, thus enhancing catalytic activity. Fourthly, producing Bi2WO6 heterostructures with other photocatalysts with matching energy bands can create synergistic effects and widen the range of degradable pollutants. Finally, creating surface defects, such as the introduction of oxygen vacancies, play a crucial role in trapping electrons and facilitating effective carrier separation, ultimately improving catalytic performance.
However, despite these improvements, obstacles and challenges remain in the research of Bi2WO6-based photocatalysts. These limitations must be overcome to fully utilize the benefits of Bi2WO6 in the field of wastewater purification. Firstly, controlling the morphology of Bi2WO6 during synthesis is typically achieved through adjusting solution pH and utilizing surfactants. However, regulating the catalytic active site remains imprecise. Furthermore, further exploration of crystal surface control methods can improve the photocatalytic activity of Bi2WO6. Secondly, the current research mostly concentrates on pollutant degradation in water environments. Nonetheless, water environments contain various types of contaminants including, but not limited to, pesticides, radioactive substances, toxic algae, and harmful organic and inorganic materials. Interactions between different pollutants can heighten the toxicity of the water body. Therefore, assessing the photocatalytic capacity of different photocatalysts in water with co-existing pollutants is necessary. Thirdly, optimizing photocatalysts to facilitate the separation of photogenerated carriers has been a primary focus. The Z-scheme heterojunction effectively separates carriers, enhances the reduction capacity of Bi2WO6, and preserves the negative electrons and positive holes. Therefore, Z-scheme heterojunctions can be achieved by combining Bi2WO6 with narrow-band gap semiconductors with a more negative CB. However, there is limited research in these areas, and the inclusion of external fields is expected to become a prominent research focus in the future. Although there have been significant developments in the preparation and degradation applications of Bi2WO6 in recent years, most studies have been conducted on a laboratory scale due to the unstable photocatalytic properties of Bi2WO6 in large-scale applications. This issue needs to be prioritized, as large-scale industrial applications of photocatalysts are crucial for environmental contaminant removal. Considering the practical applications, the toxicity of Bi2WO6-based catalysts is an important consideration. However, overall, Bi2WO6-based photocatalysts are universally recognized as green. Yet, it is important to note that Bi2WO6-based photocatalysts can generate reactive oxygen species and free radicals during their photocatalytic processes. These reactive species have the potential to cause cellular toxicity. Therefore, further research is necessary to fully understand the potential toxicity of Bi2WO6 nanomaterials, especially their effects on human health. It is critical to conduct comprehensive biosafety experiments and studies to assess the potential risks associated with the use of Bi2WO6-based photocatalysts. This will help ensure the safe and responsible use of Bi2WO6 nanomaterials in a variety of applications.

Author Contributions

Conceptualization, Y.Z. and J.Z.; validation, Y.Z. and H.Y.; writing—original draft preparation, Y.Z. and H.Y.; writing—review and editing, R.Z. and L.Y.; visualization, Q.M.; supervision, C.G. and K.Q.; funding acquisition, Y.Z., K.Q., H.Y. and C.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Basic Research Project of Yunnan Province Science and Technology Department, grant number 202201AU070004; the National Natural Science Foundation of China, grant number 52272287, 22268003; the Yunnan Province Education Department Scientific Research Fund Project, grant number: 2023J0959; 2023Y1049.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available upon request from the corresponding author. The data are not publicly available due to ethical considerations.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Xu, K.; Wang, L.; Xu, X.; Dou, S.X.; Hao, W.; Du, Y. Two Dimensionl Bismuth-Based Layered Materials for Energy-Related Applications. Energy Storage Mater. 2019, 19, 446–463. [Google Scholar] [CrossRef]
  2. Tu, S.; Guo, Y.; Zhang, Y.; Hu, C.; Zhang, T.; Ma, T.; Huang, H. Piezocatalysis and Piezo-Photocatalysis: Catalysts Classification and Modification Strategy, Reaction Mechanism, and Practical Application. Adv. Funct. Mater. 2020, 30, 2005158. [Google Scholar] [CrossRef]
  3. Wang, Z.; Cheng, B.; Zhang, L.; Yu, J.; Li, Y.; Wageh, S.; Al-Ghamdi, A.A. S-Scheme 2D/2D Bi2MoO6/BiOI van der Waals Heterojunction for CO2 Photoreduction. Chin. J. Catal. 2022, 43, 1657–1666. [Google Scholar] [CrossRef]
  4. Zhang, W.; Zhang, S.; Chen, Z.; Zhang, Z. Cobalt-Ferrite Functionalized Graphitic Carbon Nitride (CoFe2O4@g-C3N4) Nanoconfined Catalytic Membranes for Efficient Water Purification: Performance and Mechanism. J. Mater. Chem. A 2023, 11, 18933–18944. [Google Scholar] [CrossRef]
  5. Zhu, J.; Xu, W.; Guo, S.; Zhou, J.; Lu, T.; Xing, P.; Cai, Q.; Sun, R. Hazard of heavy metal pollution in water and its treatment technology. Mod. Agric. Sci. Technol. 2022, 6, 129–132. [Google Scholar]
  6. Li, J. Analysis of pretreatment methods and detection techniques of organic pollutants in water. Leather Manuf. Environ. Technol. 2022, 3, 18–20. [Google Scholar]
  7. Dai, X.; Feng, S.; Zheng, W.; Wu, W.; Zhou, Y.; Ye, Z.; Cao, X.; Wang, Y. Ag–AgBr/g-C3N4/ZIF-8 Prepared with Ionic Liquid as Template for Highly Efficient Photocatalytic Hydrogen Evolution under Visible Light. Int. J. Hydrogen Energy 2022, 47, 10603–10615. [Google Scholar] [CrossRef]
  8. Wang, X.; Ng, D.; Du, H.; Hornung, C.H.; Polyzos, A.; Seeber, A.; Li, H.; Huo, Y.; Xie, Z. Copper Decorated Indium Oxide Rods for Photocatalytic CO2 Conversion under Simulated Sun Light. J. CO2 Util. 2022, 58, 101909. [Google Scholar] [CrossRef]
  9. Adamou, P.; Harkou, E.; Hafeez, S.; Manos, G.; Villa, A.; Al-Salem, S.M.; Constantinou, A.; Dimitratos, N. Recent Progress on Sonochemical Production for the Synthesis of Efficient Photocatalysts and the Impact of Reactor Design. Ultrason. Sonochem. 2023, 100, 106610. [Google Scholar] [CrossRef]
  10. Li, S.; Cai, M.; Wang, C.; Liu, Y. Ta3N5/CdS Core-Shell S-Scheme Heterojunction Nanofibers for Efficient Photocatalytic Removal of Antibiotic Tetracycline and Cr (VI): Performance and Mechanism Insights. Adv. Fiber Mater. 2023, 5, 994–1007. [Google Scholar] [CrossRef]
  11. Yu, Y.; Huang, H. Coupled Adsorption and Photocatalysis of G-C3N4 Based Composites: Material Synthesis, Mechanism, and Environmental Applications. Chem. Eng. J. 2023, 453, 139755. [Google Scholar] [CrossRef]
  12. Li, S.; Cai, M.; Liu, Y.; Wang, C.; Yan, R.; Chen, X. Constructing Cd0.5Zn0.5S/Bi2WO6 S-Scheme Heterojunction for Boosted Photocatalytic Antibiotic Oxidation and Cr (VI) Reduction. Adv. Powder Mater. 2023, 2, 100073. [Google Scholar] [CrossRef]
  13. Jiang, Z.; Zhang, L.; Yu, J. Research Progress on S-Scheme Heterojunction Photocatalyst. J. Chin. Ceram. Soc. 2023, 51, 73–81. [Google Scholar]
  14. Yu, H.; Jiang, L.; Wang, H.; Huang, B.; Yuan, X.; Huang, J.; Zhang, J.; Zeng, G. Modulation of Bi2MoO6-Based Materials for Photocatalytic Water Splitting and Environmental Application: A Critical Review. Small 2019, 15, 1901008. [Google Scholar] [CrossRef] [PubMed]
  15. Li, X.; Xie, J.; Jiang, C.; Yu, J.; Zhang, P. Review on design and evaluation of environmental photocatalysts. Front. Environ. Sci. Eng. 2018, 12, 1–32. [Google Scholar] [CrossRef]
  16. Fujishima, A.; Honda, K. Electrochemical Photolysis of Water at a Semiconductor Electrode. Nature 1972, 238, 37–38. [Google Scholar] [CrossRef] [PubMed]
  17. Li, S.; Wang, C.; Liu, Y.; Liu, Y.; Cai, M.; Zhao, W.; Duan, X. S-Scheme MIL-101(Fe) Octahedrons Modified Bi2WO6 Microspheres for Photocatalytic Decontamination of Cr (VI) and Tetracycline Hydrochloride: Synergistic Insights, Reaction Pathways, and Toxicity Analysis. Chem. Eng. J. 2023, 455, 140943. [Google Scholar] [CrossRef]
  18. Xing, Z.; Zhang, J.; Cui, J.; Yin, J.; Zhao, T.; Kuang, J.; Xiu, Z.; Wan, N.; Zhou, W. Recent Advances in Floating TiO2-Based Photocatalysts for Environmental Application. Appl. Catal. B-Environ. 2018, 225, 452–467. [Google Scholar] [CrossRef]
  19. Ong, C.; Ng, L.; Mohammad, A. A Review of ZnO Nanoparticles as Solar Photocatalysts: Synthesis, Mechanisms and Applications. Renew. Sust. Energ. Rev. 2018, 81, 536–551. [Google Scholar] [CrossRef]
  20. Wang, L.; Liu, S.; Wang, Z.; Zhou, Y.; Qin, Y.; Wang, Z.L. Piezotronic Effect Enhanced Photocatalysis in Strained Anisotropic ZnO/TiO2 Nanoplatelets via Thermal Stress. ACS Nano 2016, 10, 2636–2643. [Google Scholar] [CrossRef]
  21. Liu, C.; Yang, Y.; Li, W.; Li, J.; Li, Y.; Chen, Q. A Novel Bi2S3 Nanowire @ TiO2 Nanorod Heterogeneous Nanostructure for Photoelectrochemical Hydrogen Generation. Chem. Eng. J. 2016, 302, 717–724. [Google Scholar] [CrossRef]
  22. Wang, X.; Liu, J.; Leong, S.; Lin, X.; Wei, J.; Kong, B.; Xu, Y.; Low, Z.-X.; Yao, J.; Wang, H. Rapid Construction of ZnO@ZIF-8 Heterostructures with Size-Selective Photocatalysis Properties. ACS Appl. Mater. Interfaces 2016, 8, 9080–9087. [Google Scholar] [CrossRef] [PubMed]
  23. Ge, L.; Zuo, F.; Liu, J.; Ma, Q.; Wang, C.; Sun, D.; Bartels, L.; Feng, P. Synthesis and Efficient Visible Light Photocatalytic Hydrogen Evolution of Polymeric G-C3N4 Coupled with CdS Quantum Dots. J. Phys. Chem. C 2012, 116, 13708–13714. [Google Scholar] [CrossRef]
  24. Wu, S.; Sun, J.; Li, Q.; Hood, Z.D.; Yang, S.; Su, T.; Peng, R.; Wu, Z.; Sun, W.; Kent, P.R.C.; et al. Effects of Surface Terminations of 2D Bi2WO6 on Photocatalytic Hydrogen Evolution from Water Splitting. ACS Appl. Mater. Interfaces 2020, 12, 20067–20074. [Google Scholar] [CrossRef]
  25. Xie, Q.; He, W.; Liu, S.; Li, C.; Zhang, J.; Wong, P.K. Bifunctional S-Scheme g-C3N4/Bi/BiVO4 Hybrid Photocatalysts toward Artificial Carbon Cycling. Chin. J. Catal. 2020, 41, 140–153. [Google Scholar] [CrossRef]
  26. Li, Y.; Liao, D.; Li, T.; Zhong, W.; Wang, X.; Hong, X.; Yu, H. Plasmonic Z-Scheme Pt-Au/BiVO4 Photocatalyst: Synergistic Effect of Crystal-Facet Engineering and Selective Loading of Pt-Au Cocatalyst for Improved Photocatalytic Performance. J. Colloid Interface Sci. 2020, 570, 232–241. [Google Scholar] [CrossRef]
  27. Jiang, T.; Wang, K.; Guo, T.; Wu, X.; Zhang, G. Fabrication of Z-Scheme MoO3/Bi2O4 Heterojunction Photocatalyst with Enhanced Photocatalytic Performance under Visible Light Irradiation. Chin. J. Catal. 2020, 41, 161–169. [Google Scholar] [CrossRef]
  28. Zhang, G.; Hu, Z.; Sun, M.; Liu, Y.; Liu, L.; Liu, H.; Huang, C.; Qu, J.; Li, J. Formation of Bi2WO6 Bipyramids with Vacancy Pairs for Enhanced Solar-Driven Photoactivity. Adv. Funct. Mater. 2015, 25, 3726–3734. [Google Scholar] [CrossRef]
  29. Lian, X.; Xue, W.; Dong, S.; Liu, E.; Li, H.; Xu, K. Construction of S-Scheme Bi2WO6/g-C3N4 Heterostructure Nanosheets with Enhanced Visible-Light Photocatalytic Degradation for Ammonium Dinitramide. J. Hazard. Mater. 2021, 412, 125217. [Google Scholar] [CrossRef]
  30. Zheng, W.; Liu, J.; Wu, Z.; Liu, M.; Zhang, H.; Han, W. Preparation of Tin Dioxide/Bismuth Tungstate Composite Photocatalytic Materials by Hydrothermal Method and Its Catalytic Activity. J. Synth. Cryst. 2022, 51, 502–507. [Google Scholar]
  31. Li, C.; Chen, G.; Sun, J.; Feng, Y.; Liu, J.; Dong, H. Ultrathin Nanoflakes Constructed Erythrocyte-like Bi2WO6 Hierarchical Architecture via Anionic Self-Regulation Strategy for Improving Photocatalytic Activity and Gas-Sensing Property. Appl. Catal. B Environ. 2015, 163, 415–423. [Google Scholar] [CrossRef]
  32. Li, C.; Chen, G.; Sun, J.; Rao, J.; Han, Z.; Hu, Y.; Zhou, Y. A Novel Mesoporous Single-Crystal-Like Bi2WO6 with Enhanced Photocatalytic Activity for Pollutants Degradation and Oxygen Production. ACS Appl. Mater. Interfaces 2015, 7, 25716–25724. [Google Scholar] [CrossRef] [PubMed]
  33. Wan, J.; Du, X.; Wang, R.; Liu, E.; Jia, J.; Bai, X.; Hu, X.; Fan, J. Mesoporous Nanoplate Multi-Directional Assembled Bi2WO6 for High Efficient Photocatalytic Oxidation of NO. Chemosphere 2018, 193, 737–744. [Google Scholar] [CrossRef]
  34. Wang, S.; Yang, H.; Yi, Z.; Wang, X. Enhanced Photocatalytic Performance by Hybridization of Bi2WO6 Nanoparticles with Honeycomb-like Porous Carbon Skeleton. J. Environ. Manag. 2019, 248, 109341. [Google Scholar] [CrossRef] [PubMed]
  35. Zhang, M.; Zhu, Y.; Li, W.; Wang, F.; Li, H.; Liu, X.; Zhang, W.; Ren, C. Double Z-Scheme System of Silver Bromide@bismuth Tungstate/Tungsten Trioxide Ternary Heterojunction with Enhanced Visible-Light Photocatalytic Activity. J. Colloid Interface Sci. 2018, 509, 18–24. [Google Scholar] [CrossRef] [PubMed]
  36. Zhang, C.; Ren, J.; Hua, J.; Xia, L.; He, J.; Huo, D.; Hu, Y. Multifunctional Bi2WO6 Nanoparticles for CT-Guided Photothermal and Oxygen-free Photodynamic Therapy. ACS Appl. Mater. Interfaces 2018, 10, 1132–1146. [Google Scholar] [CrossRef]
  37. Chang, C.; Chen, J.; Lin, K.; Wei, Y.; Chao, P.; Huang, C. Enhanced Visible-Light-Driven Photocatalytic Degradation by Metal Wire-Mesh Supported Ag/Flower-like Bi2WO6 Photocatalysts. J. Alloys Compd. 2020, 813, 152186. [Google Scholar] [CrossRef]
  38. Li, Q.; Zhu, X.; Yang, J.; Yu, Q.; Zhu, X.; Chu, J.; Du, Y.; Wang, C.; Hua, Y.; Li, H.; et al. Plasma Treated Bi2WO6 Ultrathin Nanosheets with Oxygen Vacancies for Improved Photocatalytic CO2 Reduction. Inorg. Chem. Front. 2020, 7, 597–602. [Google Scholar] [CrossRef]
  39. Huang, H.; Zhao, J.; Du, Y.; Zhou, C.; Zhang, M.; Wang, Z.; Weng, Y.; Long, J.; Hofkens, J.; Steele, J.A.; et al. Direct Z-Scheme Heterojunction of Semicoherent FAPbBr3/Bi2WO6 Interface for Photoredox Reaction with Large Driving Force. ACS Nano 2020, 14, 16689–16697. [Google Scholar] [CrossRef]
  40. Guo, W.; Jian, L.; Wang, X.; Zeng, W. Hydrothermal Synthesis of Ni-Doped Hydrangea-like Bi2WO6 and the Enhanced Gas Sensing Property to n-Butanol. Sens. Actuators B Chem. 2022, 357, 131396. [Google Scholar] [CrossRef]
  41. Sun, D.; Le, Y.; Jiang, C.; Cheng, B. Ultrathin Bi2WO6 Nanosheet Decorated with Pt Nanoparticles for Efficient Formaldehyde Removal at Room Temperature. Appl. Surf. Sci. 2018, 441, 429–437. [Google Scholar] [CrossRef]
  42. Peng, R.; Kang, Y.; Deng, X.; Zhang, X.; Xie, F.; Wang, H.; Liu, W. Topotactic Transformed Face-to-Face Heterojunction of BiOCl/Bi2WO6 for Improved Tetracycline Photodegradation. J. Environ. Chem. Eng. 2021, 9, 106750. [Google Scholar] [CrossRef]
  43. Ren, X.; Wu, K.; Qin, Z.; Zhao, X.; Yang, H. The Construction of Type II Heterojunction of Bi2WO6/BiOBr Photocatalyst with Improved Photocatalytic Performance. J. Alloys Compd. 2019, 788, 102–109. [Google Scholar] [CrossRef]
  44. Zhao, Y.; Wang, Y.; Liu, E.; Fan, J.; Hu, X. Bi2WO6 Nanoflowers: An Efficient Visible Light Photocatalytic Activity for Ceftriaxone Sodium Degradation. Appl. Surf. Sci. 2018, 436, 854–864. [Google Scholar] [CrossRef]
  45. Karbasi, M.; Hashemifar, S.J.; Karimzadeh, F.; Giannakis, S.; Pulgarin, C.; Raeissi, K.; Sienkiewicz, A. Decrypting the Photocatalytic Bacterial Inactivation of Hierarchical Flower-like Bi2WO6 Microspheres Induced by Surface Properties: Experimental Studies and Ab Initio Calculations. Chem. Eng. J. 2022, 427, 131768. [Google Scholar] [CrossRef]
  46. Zhang, L.; Wang, H.; Chen, Z.; Wong, P.; Liu, J. Bi2WO6 Micro/Nano-Structures: Synthesis, Modifications and Visible-Light-Driven Photocatalytic Applications. Appl. Catal. B 2011, 106, 1–13. [Google Scholar] [CrossRef]
  47. Yi, H.; Qin, L.; Huang, D.; Zeng, G.; Lai, C.; Liu, X.; Li, B.; Wang, H.; Zhou, C.; Huang, F.; et al. Nano-Structured Bismuth Tungstate with Controlled Morphology: Fabrication, Modification, Environmental Application and Mechanism Insight. Chem. Eng. J. 2019, 358, 480–496. [Google Scholar] [CrossRef]
  48. Zhou, Y.; Zhang, Y.; Lin, M.; Long, J.; Zhang, Z.; Lin, H.; Wu, J.C.-S.; Wang, X. Monolayered Bi2WO6 Nanosheets Mimicking Heterojunction Interface with Open Surfaces for Photocatalysis. Nat. Commun. 2015, 6, 8340. [Google Scholar] [CrossRef]
  49. Lin, S.; Liu, L.; Hu, J.; Liang, Y.; Cui, W. Nano Ag@AgBr Surface-Sensitized Bi2WO6 Photocatalyst: Oil-in-Water Synthesis and Enhanced Photocatalytic Degradation. Appl. Surf. Sci. 2015, 324, 20–29. [Google Scholar] [CrossRef]
  50. Kim, M.; Jo, W. Visible-Light-Activated N-Doped CQDs/g-C3N4/Bi2WO6 Nanocomposites with Different Component Arrangements for the Promoted Degradation of Hazardous Vapors. J. Mater. Sci. Technol. 2020, 40, 168–175. [Google Scholar] [CrossRef]
  51. Chen, T.; Liu, L.; Hu, C.; Huang, H. Recent Advances on Bi2WO6-Based Photocatalysts for Environmental and Energy Applications. Chin. J. Catal. 2021, 42, 1413–1438. [Google Scholar] [CrossRef]
  52. Linghu, X.; Shu, Y.; Liu, L.; Zhao, Y.; Zhang, J.; Chen, Z.; Shan, D.; Wang, B. Hydro/Solvothermally Synthesized Bismuth Tungstate Nanocatalysts for Enhanced Photocatalytic Degradation of Dyes, Antibiotics, and Bacteria in Wastewater: A Review. J. Water Process. Eng. 2023, 54, 103994. [Google Scholar] [CrossRef]
  53. Guo, Q.; Zhou, C.; Ma, Z.; Yang, X. Fundamentals of TiO2 Photocatalysis: Concepts, Mechanisms, and Challenges. Adv. Mater. 2019, 31, 1901997. [Google Scholar] [CrossRef] [PubMed]
  54. He, Z.; Siddique, M.S.; Yang, H.; Xia, Y.; Su, J.; Tang, B.; Wang, L.; Kang, L.; Huang, Z. Novel Z-Scheme In2S3/Bi2WO6 Core-Shell Heterojunctions with Synergistic Enhanced Photocatalytic Degradation of Tetracycline Hydrochloride. J. Clean. Prod. 2022, 339, 130634. [Google Scholar] [CrossRef]
  55. Chen, T.; Xu, C.; Zou, C.; Fan, L.; Xu, Q. Self-Assembly of PDINH/TiO2/Bi2WO6 Nanocomposites for Improved Photocatalytic Activity Based on a Rapid Electron Transfer Channel. Appl. Surf. Sci. 2022, 584, 152667. [Google Scholar] [CrossRef]
  56. Lv, Y.; He, R.; Chen, Z.; Li, X.; Xu, Y. Fabrication of Hierarchical Copper Sulfide/Bismuth Tungstate p-n Heterojunction with Two-Dimensional (2D) Interfacial Coupling for Enhanced Visible-Light Photocatalytic Degradation of Glyphosate. J. Colloid Interface Sci. 2020, 560, 293–302. [Google Scholar] [CrossRef]
  57. Guo, Y.; Chu, D. Controlled synthesis of knob-shaped Bi2WO6 micro-nano materials by hydrothermal method. J. Henan Univ. Eng. (Nat. Sci. Ed.) 2022, 34, 11–15. [Google Scholar]
  58. Zheng, C.; Yang, H.; Cui, Z. Enhanced Photocatalytic Performance of Au Nanoparticles-Modified Rose Flower-like Bi2WO6 Hierarchical Architectures. J. Ceram. Soc. Jpn. 2017, 125, 887–893. [Google Scholar] [CrossRef]
  59. Wang, H.; Wang, R.; Zhang, Y.; Zhao, F.; Su, X. Preparation and Photocatalytic Activity of Bi2O3/Bi2WO6 composite catalyst. Liaoning Chem. Ind. 2022, 51, 1497–1500. [Google Scholar]
  60. Zhou, L.; Jin, C.; Yu, Y.; Chi, F.; Lv, Y.; Ran, S. Low-temperature Solid-state Synthesis of Bi2WO6 Powders and Its Visible-light Photocatalytic Activity. Chin. J. Process Eng. 2016, 16, 895–899. [Google Scholar]
  61. Yu, M.; Pu, Q.; Liao, X.; Yu, H.; Lin, S.; Li, Z.; Yu, C.; Wang, H.; Zhong, X. Controllable Synthesis of Bismuth Tungstate Photocatalysts with Different Morphologies for Degradation of Antibiotics under Visible-Light Irradiation. J. Mater. Sci.-Mater. Electron. 2021, 32, 17848–17864. [Google Scholar] [CrossRef]
  62. Zhu, C.; Liu, Y.; Cao, H.; Sun, J.; Xu, Q.; Wang, L. Insight into the Influence of Morphology of Bi2WO6 for Photocatalytic Degradation of VOCs under Visible Light. Colloids Surf. A Physicochem. Eng. Asp. 2019, 568, 327–333. [Google Scholar] [CrossRef]
  63. Gou, Z.; Dai, J.; Bai, J. Synthesis of Mesoporous Bi2WO6 Flower-Like Spheres with Photocatalysis Properties under Visible Light. Int. J. Electrochem. Sci. 2020, 15, 10684–10693. [Google Scholar] [CrossRef]
  64. Pu, Q.; Li, Z.; Li, D. Preparation of Bismuth Tungstate Nanoscale Photocatalyst and the Study on Degradation Performance of Tetracycline Antibiotics. Synth. Mater. Aging Appl. 2018, 47, 72–75. [Google Scholar]
  65. Yang, L.; Li, X.; Wang, Z.; Zhao, J.; Dong, D.; Wang, M. Yeast-assisted Synthesis of Bismuth Tungstate Hollow Microsphere and Its Photocatalysis for Tetracycline Hydrochloride. New Chem. Mater. 2016, 44, 98–101. [Google Scholar]
  66. Liu, S.; Hou, Y.; Zheng, S.; Zhang, Y.; Wang, Y. One-Dimensional Hierarchical Bi2WO6 Hollow Tubes with Porous Walls: Synthesis and Photocatalytic Property. CrystEngComm 2013, 15, 4124–4130. [Google Scholar] [CrossRef]
  67. Yang, A.; Han, Y.; Li, S.; Xing, H.; Pan, Y.; Liu, W. Synthesis and Comparison of Photocatalytic Properties for Bi2WO6 Nanofibers and Hierarchical Microspheres. J. Alloys Compd. 2017, 695, 915–921. [Google Scholar] [CrossRef]
  68. Guo, S.; Li, X.; Wang, H.; Dong, F.; Wu, Z. Fe-Ions Modified Mesoporous Bi2WO6 Nanosheets with High Visible Light Photocatalytic Activity. J. Colloid Interface Sci. 2012, 369, 373–380. [Google Scholar] [CrossRef]
  69. Zhu, X.; Qin, F.; Zhang, X.; Zhong, Y.; Wang, J.; Jiao, Y.; Luo, Y.; Feng, W. Synthesis of Tin-Doped Three-Dimensional Flower-like Bismuth Tungstate with Enhanced Photocatalytic Activity. Int. J. Mol. Sci. 2022, 23, 8422. [Google Scholar] [CrossRef]
  70. Bunluesak, T.; Phuruangrat, A.; Thongtem, S.; Thongtem, T. Visible-Light-Driven Heterostructure Ag/Bi2WO6 Nanocomposites Synthesized by Photodeposition Method and Used for Photodegradation of Rhodamine B Dye. Res. Chem. Intermed. 2021, 47, 3079–3092. [Google Scholar] [CrossRef]
  71. Gao, X.; Fei, J.; Dai, Y.; Fu, F. Hydrothermal Synthesis of Series Cu-Doped Bi2WO6 and Its Application in Photo-Degradative Removal of Phenol in Wastewater with Enhanced Efficiency. J. Mol. Liq. 2018, 256, 267–276. [Google Scholar] [CrossRef]
  72. Zhu, F.; Lv, Y.; Li, J.; Ding, J.; Xia, X.; Wei, L.; Jiang, J.; Zhang, G.; Zhao, Q. Enhanced Visible Light Photocatalytic Performance with Metal-Doped Bi2WO6 for Typical Fluoroquinolones Degradation: Efficiencies, Pathways and Mechanisms. Chemosphere 2020, 252, 126577. [Google Scholar] [CrossRef] [PubMed]
  73. Phuruangrat, A.; Buapoon, S.; Bunluesak, T.; Suebsom, P.; Thongtem, S.; Thongtem, T. Facile Synthesis of Pd-Doped Bi2WO6 Nanoplates Used for Enhanced Visible-Light-Driven Photocatalysis. Inorg. Nano-Met. Chem. 2023, 53, 219–227. [Google Scholar]
  74. Tu, Y.; Ling, L.; Li, Q.; Long, X.; Liu, N.; Li, Z. Greatly Enhanced Photocatalytic Activity over Bi2WO6 by MIL-53(Fe) Modification. Opt. Mater. 2020, 110, 110500. [Google Scholar] [CrossRef]
  75. Tahir, N.; Zahid, M.; Bhatti, I.A.; Jamil, Y. Fabrication of Visible Light Active Mn-Doped Bi2WO6-GO/MoS2 Heterostructure for Enhanced Photocatalytic Degradation of Methylene Blue. Environ. Sci. Pollut. Res. 2022, 29, 6552–6567. [Google Scholar] [CrossRef] [PubMed]
  76. Su, H.; Li, S.; Xu, L.; Liu, C.; Zhang, R.; Tan, W. Hydrothermal Preparation of Flower-like Ni2+ Doped Bi2WO6 for Enhanced Photocatalytic Degradation. J. Phys. Chem. Solids 2022, 170, 110954. [Google Scholar] [CrossRef]
  77. Sun, C.; Zhang, K.; Wang, B.; Wang, R. Synergistic Effect of Amorphous Ti(IV)-Hole and Ni(II)-Electron Cocatalysts for Enhanced Photocatalytic Performance of Bi2WO6. Catalysts 2022, 12, 1633. [Google Scholar] [CrossRef]
  78. Pinchujit, S.; Phuruangrat, A.; Wannapop, S.; Sakhon, T.; Kuntalue, B.; Thongtem, T.; Thongtem, S. Synthesis and Characterization of Heterostructure Pt/Bi2WO6 Nanocomposites with Enhanced Photodegradation Efficiency Induced by Visible Radiation. Solid State Sci. 2022, 134, 107064. [Google Scholar] [CrossRef]
  79. Song, X.C.; Li, W.T.; Huang, W.Z.; Zhou, H.; Yin, H.Y.; Zheng, Y.F. Enhanced Photocatalytic Activity of Cadmium-Doped Bi2WO6 Nanoparticles under Simulated Solar Light. J. Nanopart. Res. 2015, 17, 134. [Google Scholar] [CrossRef]
  80. Phuruangrat, A.; Buapoon, S.; Bunluesak, T.; Suebsom, P.; Wannapop, S.; Thongtem, T.; Thongtem, S. Hydrothermal Preparation of Au-Doped Bi2WO6 Nanoplates for Enhanced Visible-Light-Driven Photocatalytic Degradation of Rhodamine B. Solid State Sci. 2022, 128, 106881. [Google Scholar] [CrossRef]
  81. Hojamberdiev, M.; Kadirova, Z.C.; Zahedi, E.; Onna, D.; Claudia Marchi, M.; Zhu, G.; Matsushita, N.; Hasegawa, M.; Aldabe Bilmes, S.; Okada, K. Tuning the Morphological Structure, Light Absorption, and Photocatalytic Activity of Bi2WO6 and Bi2WO6-BiOCl through Cerium Doping. Arab. J. Chem. 2020, 13, 2844–2857. [Google Scholar] [CrossRef]
  82. Wang, Z.; Fu, N.; Yu, H.; Xu, J.; He, Q.; Zheng, S.; Ding, B.; Yan, X. Enhancing oxygen vacancy photocatalytic efficiency of bismuth tungstate using In-doped W site. Acta Phys. Sin. 2019, 68, 217102. [Google Scholar] [CrossRef]
  83. Kumar, R.; Raizada, P.; Verma, N.; Hosseini-Bandegharaei, A.; Thakur, V.K.; Le, Q.V.; Nguyen, V.-H.; Selvasembian, R.; Singh, P. Recent Advances on Water Disinfection Using Bismuth Based Modified Photocatalysts: Strategies and Challenges. J. Clean. Prod. 2021, 297, 126617. [Google Scholar] [CrossRef]
  84. Ferreira, V.R.A.; Santos, P.R.M.; Silva, C.I.Q.; Azenha, M.A. Latest Developments on TiO2-Based Photocatalysis: A Special Focus on Selectivity and Hollowness for Enhanced Photonic Efficiency. Appl. Catal. A Gen. 2021, 623, 118243. [Google Scholar] [CrossRef]
  85. Li, P.; Zhao, X.; Dai, J.; Han, Y.; Jiang, J.; Zhang, Y. Preparation of Large-Faced Flower-like Bi2WO6 Using Carbon as a Template to Enhanced Photocatalytic Activity under Visible Light. J. Phys. Chem. Solids 2022, 171, 110968. [Google Scholar] [CrossRef]
  86. Zhang, Y.; Zhao, Y.; Xiong, Z.; Gao, T.; Gong, B.; Liu, P.; Liu, J.; Zhang, J. Elemental Mercury Removal by I−-Doped Bi2WO6 with Remarkable Visible-Light-Driven Photocatalytic Oxidation. Appl. Catal. B Environ. 2021, 282, 119534. [Google Scholar] [CrossRef]
  87. Zheng, X.; Tang, Q.; Zhang, H.; Lu, S.; Yang, F. Bi2WO6/SiC Composite Photocatalysts with Enhanced Photocatalytic Performance for Dyes Degradation. Inorg. Chem. Commun. 2022, 140, 109434. [Google Scholar] [CrossRef]
  88. Zhu, J.; Zhou, Y.; Wu, W.; Deng, Y.; Xiang, Y. A Novel Rose-Like CuS/Bi2WO6 Composite for Rhodamine B Degradation. ChemistrySelect 2019, 4, 11853–11861. [Google Scholar] [CrossRef]
  89. Liu, W.; Qi, K.; Wang, Y.; Wen, F.; Wang, J. Halogen-Induced Polymorphic Bi2WO6-xHalogen2x with Highly Photocatalytic Performance and Mechanism Investigation. Appl. Surf. Sci. 2022, 600, 154160. [Google Scholar] [CrossRef]
  90. Wei, Y.; Wei, X.; Guo, S.; Huang, Y.; Zhu, G.; Zhang, J. The Effects of Br Dopant on the Photo-Catalytic Properties of Bi2WO6. Mater. Sci. Eng. B 2016, 206, 79–84. [Google Scholar] [CrossRef]
  91. Zhao, Y.; Liang, X.; Hu, X.; Fan, J. RGO/Bi2WO6 Composite as a Highly Efficient and Stable Visible-Light Photocatalyst for Norfloxacin Degradation in Aqueous Environment. J. Colloid Interface Sci. 2021, 589, 336–346. [Google Scholar] [CrossRef] [PubMed]
  92. Hoang, L.H.; Phu, N.D.; Peng, H.; Chen, X. High Photocatalytic Activity N-Doped Bi2WO6 Nanoparticles Using a Two-Step Microwave-Assisted and Hydrothermal Synthesis. J. Alloys Compd. 2018, 744, 228–233. [Google Scholar] [CrossRef]
  93. Sun, H.; Zou, C.; Tang, W. Designing Double Z-Scheme Heterojunction of g-C3N4/Bi2MoO6/Bi2WO6 for Efficient Visible-Light Photocatalysis of Organic Pollutants. Colloids Surf. A Physicochem. Eng. Asp. 2022, 654, 130105. [Google Scholar] [CrossRef]
  94. Zhao, N.; Zhang, Y.; Liu, M.; Peng, Y.; Liu, J. 2D-2D WO3-Bi2WO6 Photocatalyst with an S-Scheme Heterojunction for Highly Efficient Cr (VI) Reduction. CrystEngComm 2022, 24, 6902–6909. [Google Scholar] [CrossRef]
  95. Huang, H.; Xiao, K.; He, Y.; Zhang, T.; Dong, F.; Du, X.; Zhang, Y. In Situ Assembly of BiOI@Bi12O17Cl2 P-n Junction: Charge Induced Unique Front-Lateral Surfaces Coupling Heterostructure with High Exposure of BiOI {001} Active Facets for Robust and Nonselective Photocatalysis. Appl. Catal. B Environ. 2016, 199, 75–86. [Google Scholar] [CrossRef]
  96. Wen, X.; Zhang, C.; Niu, C.; Zhang, L.; Zeng, G.; Zhang, X. Highly Enhanced Visible Light Photocatalytic Activity of CeO2 through Fabricating a Novel p-n Junction BiOBr/CeO2. Catal. Commun. 2017, 90, 51–55. [Google Scholar] [CrossRef]
  97. Kong, X.; Lee, W.; Mohamed, A.; Chai, S. Effective Steering of Charge Flow through Synergistic Inducing Oxygen Vacancy Defects and P-n Heterojunctions in 2D/2D Surface-Engineered Bi2WO6/BiOI Cascade: Towards Superior Photocatalytic CO2 Reduction Activity. Chem. Eng. J. 2019, 372, 1183–1193. [Google Scholar] [CrossRef]
  98. Lu, Y.; Sun, Y.; Li, J.; Xu, Y.; Han, Q.; Wei, L.; Sun, J.; Guo, J. Preparation of a Novel P-n BiOI/ Bi2WO6 Photocatalyst and Its Application in the Treatment of Tetracycline. J. Mater. Sci. Mater. Electron. 2022, 33, 23212–23223. [Google Scholar] [CrossRef]
  99. Ma, Q.; Chen, Q. EPR, DFT, and Mott–Schottky Study on Visible Light Photocatalytic Activity of Au and Co3O4 Mediated Bi2WO6: Role of SPR and Multi-Valence States. J. Mater. Sci. Mater. Electron. 2022, 33, 21363–21383. [Google Scholar] [CrossRef]
  100. Lu, C.; Yang, D.; Wang, L.; Wen, S.; Cao, D.; Tu, C.; Gao, L.; Li, Y.; Zhou, Y.; Huang, W. Facile Construction of CoO/Bi2WO6 p-n Heterojunction with Following Z-Scheme Pathways for Simultaneous Elimination of Tetracycline and Cr (VI) under Visible Light Irradiation. J. Alloys Compd. 2022, 904, 164046. [Google Scholar] [CrossRef]
  101. Mao, W.; Zhang, L.; Wang, T.; Bai, Y.; Guan, Y. Fabrication of Highly Efficient Bi2WO6/CuS Composite for Visible-Light Photocatalytic Removal of Organic Pollutants and Cr (VI) from Wastewater. Front. Environ. Sci. Eng. 2021, 15, 52. [Google Scholar] [CrossRef]
  102. Hu, W.; Liu, W. CuAlO2 /Bi2WO6: A Novel p–n Type Composite with Significantly Enhanced Visible-Light Photocatalytic Reduction of Cr (VI). Mater. Res. Express 2021, 8, 065901. [Google Scholar] [CrossRef]
  103. Xie, T.; Liu, Y.; Wang, H.; Wu, Z. Layered MoSe2/Bi2WO6 Composite with P-N Heterojunctions as a Promising Visible-Light Induced Photocatalyst. Appl. Surf. Sci. 2018, 444, 320–329. [Google Scholar] [CrossRef]
  104. Ng, B.; Putri, L.K.; Kong, X.Y.; Teh, Y.W.; Pasbakhsh, P.; Chai, S. Z-Scheme Photocatalytic Systems for Solar Water Splitting. Adv. Sci. 2020, 7, 1903171. [Google Scholar] [CrossRef] [PubMed]
  105. Li, Z.; Chen, S.; Li, Z.; Sun, J.; Yang, J.; Wei, J.; Wang, S.; Song, H.; Hou, Y. Visible Light Driven Antibiotics Degradation Using S-Scheme Bi2WO6/CoIn2S4 Heterojunction: Mechanism, Degradation Pathways and Toxicity Assessment. Chemosphere 2022, 303, 135113. [Google Scholar] [CrossRef] [PubMed]
  106. Hu, W.; Wu, F.; Liu, W. Construction of S-Scheme Heterojunction by Doping Bi2WO6 into Bi2O3 for Efficiently Enhanced Visible-Light Photocatalytic Performance. J. Mater. Sci. 2022, 57, 4265–4282. [Google Scholar] [CrossRef]
  107. Shandilya, P.; Guleria, A.; Fang, B. A Magnetically Recyclable Dual Step-Scheme Bi2WO6/Fe2O3/WO3 Heterojunction for Photodegradation of Bisphenol-A from Aqueous Solution. J. Environ. Chem. Eng. 2021, 9, 106461. [Google Scholar] [CrossRef]
  108. Zhang, Z.; Lin, Y.; Liu, F. Preparation and Photocatalytic Performance of CdS@Bi2WO6 Hybrid Nanocrystals. J. Alloys Compd. 2021, 889, 161668. [Google Scholar] [CrossRef]
  109. Wu, X.; Xu, J.; Zhu, P.; Liu, M.; Duan, M.; Zhang, S. High Performance Visible Light Response of a Z-Type Bi2WO6/BiOBr/RGO Heterojunction Photocatalyst for the Degradation of Norfloxacin. Dalton Trans. 2022, 51, 17994–18009. [Google Scholar] [CrossRef]
  110. Wang, Y.; Xu, F.; Sun, L.; Li, Y.; Liao, L.; Guan, Y.; Lao, J.; Yang, Y.; Zhou, T.; Wang, Y.; et al. A Highly Active Z-Scheme SnS/Zn2SnO4 Photocatalyst Fabricated for Methylene Blue Degradation. RSC Adv. 2022, 12, 31985–31995. [Google Scholar] [CrossRef]
  111. Jin, K.; Qin, M.; Li, X.; Wang, R.; Zhao, Y.; Wang, H. Z-Scheme Au@TiO2/Bi2WO6 Heterojunction as Efficient Visible-Light Photocatalyst for Degradation of Antibiotics. J. Mol. Liq. 2022, 364, 120017. [Google Scholar] [CrossRef]
  112. Sattari, M.; Farhadian, M.; Reza Solaimany Nazar, A.; Moghadam, M. Enhancement of Phenol Degradation, Using of Novel Z-Scheme Bi2WO6/C3N4/TiO2 Composite: Catalyst and Operational Parameters Optimization. J. Photochem. Photobiol. A Chem. 2022, 431, 114065. [Google Scholar] [CrossRef]
  113. Ma, C.; Ding, Y.; Ding, X.; Zhao, L.; Xu, Z.; Gao, X.; Chen, D. Synthesis of Z-Scheme g-C3N4/Gd-Doped Bi2WO6 Heterojunction with Enhanced Visible-Light Photodegradation of Organic Dyes. J. Mater. Sci. Mater. Electron. 2022, 33, 14545–14555. [Google Scholar] [CrossRef]
  114. Jin, J.; Sun, J.; Lv, K.; Guo, X.; Hou, Q.; Liu, J.; Wang, J.; Bai, Y.; Huang, X. Oxygen Vacancy BiO2-x/Bi2WO6 Synchronous Coupling with Bi Metal for Phenol Removal via Visible and near-Infrared Light Irradiation. J. Colloid Interface Sci. 2022, 605, 342–353. [Google Scholar] [CrossRef] [PubMed]
  115. Song, N.; Zhang, S.; Zhong, S.; Su, X.; Ma, C. A Direct Z-Scheme Polypyrrole/Bi2WO6 Nanoparticles with Boosted Photogenerated Charge Separation for Photocatalytic Reduction of Cr (VI): Characteristics, Performance, and Mechanisms. J. Clean. Prod. 2022, 337, 130577. [Google Scholar] [CrossRef]
  116. Zhang, Q.; Wang, M.; Ao, M.; Luo, Y.; Zhang, A.; Zhao, L.; Yan, L.; Deng, F.; Luo, X. Solvothermal Synthesis of Z-Scheme AgIn5S8/Bi2WO6 Nano-Heterojunction with Excellent Performance for Photocatalytic Degradation and Cr (VI) Reduction. J. Alloys Compd. 2019, 805, 41–49. [Google Scholar] [CrossRef]
  117. Maarisetty, D.; Baral, S.S. Defect Engineering in Photocatalysis: Formation, Chemistry, Optoelectronics, and Interface Studies. J. Mater. Chem. A 2020, 8, 18560–18604. [Google Scholar] [CrossRef]
  118. Gao, W.; Li, G.; Wang, Q.; Zhang, L.; Wang, K.; Pang, S.; Zhang, G.; Lv, L.; Liu, X.; Gao, W.; et al. Ultrathin Porous Bi2WO6 with Rich Oxygen Vacancies for Promoted Adsorption-Photocatalytic Tetracycline Degradation. Chem. Eng. J. 2023, 464, 142694. [Google Scholar] [CrossRef]
  119. Hang, X.; Zhang, Y.; Li, H.; Wang, Y.; Xiang, M.; Yu, W.; Huang, H.; Ou, H. Surface Cationic and Anionic Dual Vacancies Enhancing Photocatalytic Activity of Bi2WO6. Appl. Surf. Sci. 2022, 602, 154311. [Google Scholar]
  120. Okada, Y. Synthetic Semiconductor Photoelectrochemistry. Chem. Rec. 2021, 21, 2223–2238. [Google Scholar] [CrossRef]
  121. Zhang, Y.; Guo, W.; Zhang, Y.; Wei, W.D. Plasmonic Photoelectrochemistry: In View of Hot Carriers. Adv. Mater. 2021, 33, 2006654. [Google Scholar] [CrossRef] [PubMed]
  122. Wang, H.; Liang, Y.; Liu, L.; Hu, J.; Cui, W. Reduced Graphene Oxide Wrapped Bi2WO6 Hybrid with Ultrafast Charge Separation and Improved Photoelectrocatalytic Performance. Appl. Surf. Sci. 2017, 392, 51–60. [Google Scholar] [CrossRef]
  123. Pedanekar, R.S.; Madake, S.B.; Narewadikar, N.A.; Mohite, S.V.; Patil, A.R.; Kumbhar, S.M.; Rajpure, K.Y. Photoelectrocatalytic Degradation of Rhodamine B by Spray Deposited Bi2WO6 Photoelectrode under Solar Radiation. Mater. Res. Bull. 2022, 147, 11163. [Google Scholar] [CrossRef]
Molecules 28 08011 g001
Figure 1. According to data obtained from the Web of Science, the figure displays the number of publications related to the keywords ‘Bi2WO6’ and ‘photocatalytic’.
Figure 1. According to data obtained from the Web of Science, the figure displays the number of publications related to the keywords ‘Bi2WO6’ and ‘photocatalytic’.
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Molecules 28 08011 g002
Figure 2. Illustrates important features of Bi2WO6 [47]. (a) It presents the crystal structure of Bi2WO6 [51]. (b) The figure showcases the redox potentials of different species and the energy band positions of Bi2WO6.
Figure 2. Illustrates important features of Bi2WO6 [47]. (a) It presents the crystal structure of Bi2WO6 [51]. (b) The figure showcases the redox potentials of different species and the energy band positions of Bi2WO6.
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Molecules 28 08011 g003
Figure 3. Schematic of photocatalytic pollutants degradation on the Bi2WO6 catalysts [52].
Figure 3. Schematic of photocatalytic pollutants degradation on the Bi2WO6 catalysts [52].
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Molecules 28 08011 g004
Figure 4. SEM images of (A) knob-like [57], (B) rose-like [58], (C) nanosheets [59], and (D) powder [60] Bi2WO6 catalyst.
Figure 4. SEM images of (A) knob-like [57], (B) rose-like [58], (C) nanosheets [59], and (D) powder [60] Bi2WO6 catalyst.
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Figure 5. Mechanism of photocatalytic degradation of tetracycline by Bi2WO6 catalyst [61].
Figure 5. Mechanism of photocatalytic degradation of tetracycline by Bi2WO6 catalyst [61].
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Figure 6. Schematic illustration of the three different types of semiconductor heterojunction photocatalysts.
Figure 6. Schematic illustration of the three different types of semiconductor heterojunction photocatalysts.
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Figure 7. (a) Band positions of BOI and Bi2WO6-OV. (b) The process of charge transfer and separation of p-n heterojunction.
Figure 7. (a) Band positions of BOI and Bi2WO6-OV. (b) The process of charge transfer and separation of p-n heterojunction.
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Molecules 28 08011 g008
Figure 8. Schematic illustration of the liquid-phase Z-scheme system, the all-solid-state Z-scheme system, and the direct Z-scheme system.
Figure 8. Schematic illustration of the liquid-phase Z-scheme system, the all-solid-state Z-scheme system, and the direct Z-scheme system.
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Figure 9. Electron paramagnetic resonance spectra of bulk Bi2WO6, VO-poor Bi2WO6, and VO-rich Bi2WO6 (a); O2 inneiring teracts with the (b) VO-rich Bi2WO6 and VO-poor Bi2WO6.
Figure 9. Electron paramagnetic resonance spectra of bulk Bi2WO6, VO-poor Bi2WO6, and VO-rich Bi2WO6 (a); O2 inneiring teracts with the (b) VO-rich Bi2WO6 and VO-poor Bi2WO6.
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Table 1. Morphology regulation of bismuth tungstate photocatalyst.
Table 1. Morphology regulation of bismuth tungstate photocatalyst.
PollutantsMorphologyPrecursorMethodEfficiencyReference
methylbenzeneNest-likeBi(NO3)3·5H2O
Na2WO4		hydrothermal100%[62]
tetracyclineFlower-likeNa2WO4·2H2O
Bi(NO3)3·5H2O		hydrothermal88%[63]
tetracyclineNanosheet(NH4)10H2(W2O7)6
Bi(NO3)3·5H2O		hydrothermal70%[64]
tetracycline hydrochlorideHollow microspheresNa2WO4·2H2O
Bi(NO3)3·5H2O		precipitation95%[65]
RhBTube-likeBi2O3
Na2WO4·2H2O		solvothermal99%[66]
RhBNanofiberNa2WO4·2H2O
Bi(NO3)3·5H2O		electrospinning71%[67]
Table 2. Metal doping of bismuth tungstate photocatalysts.
Table 2. Metal doping of bismuth tungstate photocatalysts.
PhotocatalystMethodModified Band Gap ValuePollutantsEfficiencyReference
Pd/Bi2WO6hydrothermal/RhB99.33%[73]
MIL-53(Fe)/Bi2WO6hydrothermal2.61 eVphenol98%[74]
Mn-doped Bi2WO6/GO/MoS2hydrothermal
ultrasonic		2.2 eVmethylene blue99%[75]
Ni/Bi2WO6hydrothermal2.74 eVRhB93%[76]
Ni/Ti-Bi2WO6hydrothermal2.89 eVtetracycline92.9%[77]
Pt/Bi2WO6precipitation3.08 eVRhB98.09%[78]
Cd-Bi2WO6hydrothermal2.58 eVRhB100%[79]
Au-Bi2WO6hydrothermal2.96 eVRhB96.25%[80]
Ce-Bi2WO6hydrothermal2.23~2.26 eVsalicylic acid91.6%[81]
In-Bi2WO6sol-gel2.74 eVRhB90%[82]
Table 3. Non-metal doping of bismuth tungstate.
Table 3. Non-metal doping of bismuth tungstate.
Doping ElementMethodModified Band Gap ValuePollutantsEfficiencyReference
Isolvothermal
microwave		2.29 eVRhB99%[89]
Brhydrothermal0.916 eVRhB95%[90]
rGOhydrothermal/norfloxacin87.49%[91]
Nhydrothermal
microwave		/RhB81%[92]
Table 4. Heterostructure of bismuth tungstate photocatalyst.
Table 4. Heterostructure of bismuth tungstate photocatalyst.
HeterostructureCatalystMethodPollutantsEfficiencyReference
S-schemeBi2WO6/CoIn2S4hydrothermaltetracycline90%[105]
Bi2WO6/Bi2O3triturationnitrobenzene95.7%[106]
Bi2WO6/Fe2O3/WO3ultrasonic immersingbisphenol A99%[107]
CdS@Bi2WO6solvothermalRhB96.1%[108]
Z-schemeBi2WO6/BiOBr/rGOhydrothermalnorfloxacin95.12%[109]
SnS/Zn2SnO4hydrothermalmethylene blue94.5%[110]
Au@TiO2/Bi2WO6sol-geltetracycline95%[111]
Bi2WO6/C3N4/TiO2sol-gelphenol84.7%[112]
g-C3N4/Gd/Bi2WO6hydrothermalmethylene blue92%[113]
BiO2−x/Bi2WO6solvothermalphenol90%[114]
polypyrrole/Bi2WO6precipitationCr (VI)99.7%[115]
AgIn5S8/Bi2WO6solvothermalCr (VI)92%[116]
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Zhang, Y.; Yu, H.; Zhai, R.; Zhang, J.; Gao, C.; Qi, K.; Yang, L.; Ma, Q. Recent Progress in Photocatalytic Degradation of Water Pollution by Bismuth Tungstate. Molecules 2023, 28, 8011. https://doi.org/10.3390/molecules28248011

AMA Style

Zhang Y, Yu H, Zhai R, Zhang J, Gao C, Qi K, Yang L, Ma Q. Recent Progress in Photocatalytic Degradation of Water Pollution by Bismuth Tungstate. Molecules. 2023; 28(24):8011. https://doi.org/10.3390/molecules28248011

Chicago/Turabian Style

Zhang, Yingjie, Huijuan Yu, Ruiqi Zhai, Jing Zhang, Cuiping Gao, Kezhen Qi, Li Yang, and Qiang Ma. 2023. "Recent Progress in Photocatalytic Degradation of Water Pollution by Bismuth Tungstate" Molecules 28, no. 24: 8011. https://doi.org/10.3390/molecules28248011

APA Style

Zhang, Y., Yu, H., Zhai, R., Zhang, J., Gao, C., Qi, K., Yang, L., & Ma, Q. (2023). Recent Progress in Photocatalytic Degradation of Water Pollution by Bismuth Tungstate. Molecules, 28(24), 8011. https://doi.org/10.3390/molecules28248011

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