Next Article in Journal
New Power Quality Measurement Techniques and Indices in DC and AC Networks
Next Article in Special Issue
Gel Fuels: Preparing, Rheology, Atomization, Combustion
Previous Article in Journal
Sintering of Industrial Uranium Dioxide Pellets Using Microwave Radiation for Nuclear Fuel Fabrication
Previous Article in Special Issue
Influence of Densification on the Pyrolytic Behavior of Agricultural Biomass Waste and the Characteristics of Pyrolysis Products
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Stannous Tungstate Semiconductor for Photocatalytic Degradation and Photoelectrochemical Water Splitting: A Review

School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
Author to whom correspondence should be addressed.
Energies 2022, 15(23), 9194;
Submission received: 23 October 2022 / Revised: 19 November 2022 / Accepted: 1 December 2022 / Published: 4 December 2022
(This article belongs to the Collection Energy-Efficient Chemistry)


The use of photocatalysis and photoelectrocatalysis is expected to achieve the efficient utilization of solar energy to alleviate and even solve the problems of energy depletion and environmental pfollution. At present, stannous tungstate materials have attracted extensive attention in the fields of photocatalysis and photoelectrocatalysis as favorable candidates for such utilization because of their narrow band gap energy (which is ~1.7 eV for the α phase and ~2.7 eV for the β phase, respectively) and unique band structure (which covers the oxidation and reduction potential of water). However, their practical application is still limited by excessive electron–hole recombination and poor stability. In this review, basic information (crystal and electronic structures) related to photocatalysis and photoelectrocatalysis is presented. Additionally, various strategies to enhance the photocatalytic and photoelectrochemical properties of stannous tungstate materials, such as morphological modification, crystal facet engineering, doping modification, and multicomponent compositing, are summarized. Furthermore, the achievements and difficulties of the relevant studies are discussed. The information presented in this review can provide a reference for subsequent research on the photocatalytic and photoelectrochemical performance of tungstate-based materials.

1. Introduction

With the rapid development of technology, energy has become a necessity for social operation, and the human consumption of non-renewable traditional energy (from sources such as oil and coal) is decreasing. The energy crisis has become an urgent problem that needs to be solved. Therefore, researchers are enthusiastically looking for alternative renewable clean energy sources. Among the many potential energy sources, solar energy has attracted significant attention due to its large reserves and reproducibility. Although solar energy exhibits a variety of excellent properties, its dispersion, instability and intermittency have led to its low utilization. Therefore, exploring efficient ways to better use solar energy is necessary for the generation of alternative power. Photocatalytic and photoelectrochemical methods show promise for degrading pollutants and generating new kinds of energy (such as hydrogen and chemical) via the use of solar energy. All the relevant reactions are completed by the photo-generated holes and electrons; thus, they follow a similar principle. Since the first report of TiO2 in 1972 [1], different kinds of materials with a smaller band gap than that of TiO2 (3.0–3.2 eV) have been explored [2].
One of these materials is stannous tungstate (SnWO4), which is a potential catalyst due to its narrow band gap, suitable band position, and nontoxicity [3]. However, due to its low charge separation efficiency and poor stability [4], its photocatalytic and photoelectrochemical performance has not met theoretical expectations. To solve this problem, many researchers are committed to obtaining a better catalytic performance and higher solar energy efficiency by means of morphology control, doping, and multi-component compositing. In this paper, we describe the synthesis method, physical characteristics, and activities regarding the photocatalysis and photoelectrocatalysis of stannous tungstate. In addition, the challenges and future outlook regarding the use of stannous tungstate in photoelectrochemical water splitting are summarized.

2. Structure, Properties, and Synthesis of SnWO4

In the 1970s, Jeitschko and Sleight reported the crystalline structure and morphology of the low-temperature (α) and high-temperature (β) phases of stannous tungstate materials [5,6]. Orthorhombic α-SnWO4(Figure 1a) exhibits a stable structure below 670 °C, and it tends to transform into cubic β-SnWO4 (Figure 1b) above 670 °C [7]. A reverse transition from the β-phase to the α-phase may occur under negative pressure, and the W is replaced by Mo [8]. In the crystal of α-SnWO4, W and O form WO6 octahedral structures that are interconnected in four corners, while O binds to Sn in a regular octahedral form [5]. For β-SnWO4, the W atoms of β- form WO42− tetrahedrons with O and disperse within the crystal, whereas near the Sn atoms, O is bound to it as a twisted octahedron [6].
This difference in structure leads to different properties for the α and β phases. The W-O bond in the WO42− tetrahedron (~1.75 Å) [5] is shorter than that in the WO6 octahedrons (~1.80–2.15 Å) [6]. It leads to a larger crystal field-splitting energy and a higher orbital energy of W in β-SnWO4. The conduction band edge of the α phase is mainly composed of a W 5d orbital, while the β phase contains an Sn 5p orbital, in addition to the W 5d orbital (Figure 2). The valence bands of both SnWO4 are formed by hybridizing the O 2p and Sn 5s orbitals, and the Sn-O bonds are almost identical in length (~2.20–2.80 Å) [5,6]. Thus, the positions of the valence bands are similar. These characteristics result in a narrower band gap for α-SnWO4 (~1.7 eV) than for β-SnWO4 (~2.7 eV) [3], and α-SnWO4 has a wider range of light absorption and a higher theoretical photocurrent density (~17 mA cm−2 [9]) than β-SnWO4. In addition, the β phase is a direct band gap and the α phase is an indirect band gap [3], which leads to a higher carrier separation efficiency for the α phase than the β phase [10]. Due to the wider band gap, the photo-generated electrons (holes) of β-SnWO4 show a more significant reduction (oxidation) activity. Thus, β-SnWO4 was used in photocatalysis, and only α-SnWO4 has been used in photoelectrochemical water splitting and sulfite oxidation. However, in addition to the excellent optical properties mentioned above, the use of stannous tungstate exhibits problems that urgently need to be solved. Since Sn is divalent and oxidizable in SnWO4, it is susceptible to photocorrosion, which is attributed to stannous, and the following reaction occurs: SnWO4 + H2O + 2h+ → SnO2 + WO3 + 2H+. Therefore, SnWO4 has poor stability, which limits its performance in practical applications [4]. At the same time, a recombination of carriers occurs in the diffusion process of SnWO4. Its diffusion length is short, which limits the number of photo-generated carriers that can arrive at the surface of the crystal, leading to unsatisfactory photocatalytic and photoelectrochemical performance.
Various methods have been developed to synthesize SnWO4 materials, and their differences in thermodynamic stability lead to changes in the synthesis of α-SnWO4 and β-SnWO4. Because the α phase is a kind of crystalline phase at low temperatures, its synthesis conditions are milder. Many methods can be used to synthesize the α phase, e.g., hydrothermal methods, solid–solid reaction methods [3,11,12,13], and magnetron sputtering methods [10,14,15]. Each synthesis method has its own advantages. The hydrothermal method can be used to obtain crystals with a complete crystal phase, small particle size, and uniform distribution. A magnetron sputtering method can obtain dense and uniform high-quality thin films. The solid–solid reaction method possesses a simple process and a large output. However, the synthesis of the high-temperature crystalline β-phase is relatively harsh because it requires higher temperature conditions (which should be obtained by rapid cooling at more than 940 K). It has been reported that most β-SnWO4 powders are synthesized with a high-temperature solid phase method [11,12,16,17]. β-SnWO4 can also be obtained by using NaWO4 as a raw material through kinetic control under more mild conditions [18]. Jan Ungelenk and Claus Feldmann synthesized β-SnWO4 using a microemulsion method at low temperatures [19]. When W and O combine to form a discrete WO42− tetrahedron in NaWO4, the structure is similar to that of β-SnWO4, so Na2WO4 is likely to be directly converted to β-SnWO4. Additionally, assisted by hydrothermal [20,21] and microwave-assisted hydrothermal methods [22], α-SnWO4 can also be synthesized using NaWO4 and SnCl2 as the precursors.
To synthesize the film for photoelectrochemical water spliting, an indirect or direct coating method can be used. In indirect coating, as-prepared SnWO4 powders are drop-cast onto conductive substrates. This is an easy-to-perform method, but the performance of the photoanode is weak due to the poor charge transfer caused by bad connections between the particles. For direct coating, Moritz Kölbach et al. employed a pulsed laser-deposited method that used an α-SnWO4 target formed by annealing WO3 (99.99%) and SnO (99.99%) powders [23]. Bozheyev et al. reported on the use of a magnetron co-sputtering method in which Sn (99.99%) and W (99.95%) were the targets, and the deposition was performed with the existence of O2 [24]. Recently, Gottesman used a new method—rapid thermal processing—to synthesize an α-SnWO4 film. The technique could be used to treat a sample at higher temperatures, without destroying the glass-based F:SnO2 (FTO), and a desired crystallinity with few defects was obtained [25]. Liu et al. used a chemical vapor deposition to convert WO3 into α-SnWO4, and the reaction is shown in Equation (1) [26]. An in situ hydrothermal conversion method was also reported, in which WO3 was used as a precursor to react with Sn2+ in the solution [27]. The possible reactions occurring in this method are illustrated as Equations (2)–(3) [28]. As a result, the α-SnWO4 film exhibits similar nanostructured array morphology to that of WO3 films due to the inherited behavior (Figure 3) [28]. The anion in hydrothermal conversion solutions may also affect the morphology of α-SnWO4 films [29].
4WO3 + 3SnCl2 ⇌ 3SnWO4 + WCl6
WO 3   +   H 2 O 2 H +   +   WO 4 2
W O 4 2   +   Sn 2 + SnWO 4
Generally speaking, SnWO4 has good optical properties, such as a narrow band gap and a special band structure, which results in excellent application prospects for the fields of photocatalysis and photoelectrocatalysis (especially in the field of water splitting). However, it is necessary to pay attention to the instability and short carrier diffusion length of the material itself. Furthermore, because of the differences in crystal structure and band structure between the two crystal phases (α phase and β phase), their properties and synthesis methods are different. For instance, the photo-generated electrons (holes) of the β phase have more significant reduction (oxidation) activity than that of the α phase, so the β phase is suitable for photocatalytic degradation. The α phase has a wider light absorption range and higher carrier separation efficiency, so it has potential for use in photoelectrocatalysis.

3. Research on Modification of SnWO4

Since Cho et al. first reported its optical properties in 2009 [3], SnWO4 has been widely used in photocatalytic degradation [30] and photoelectrochemical water splitting [31]. Researchers have been working to modify SnWO4 via morphological modification, facet regulations, doping, and the construction of multicomponent composites in order to obtain better photocatalytic degradation rates of organic pollutants (Table 1), as well as improved photoelectrochemical water splitting and sulfite oxidation performance (Table 2).

3.1. Morphological Modification

By regulating the synthesis technique, which is a universal method for enhancing the catalytic performance of a material, a target material with a specific morphology can be obtained. The morphology of a material is usually designed for the following purposes [57]: (1) to increase the specific surface area and reduce the nanometer size, as a high specific surface area can provide more active sites, and a small nanometer size can provide a shorter charge transfer path that improves carrier separation efficiency and enhances light absorption efficiency; (2) to improve the crystallinity of materials, as a high crystallinity can reduce the recombination center and improve carrier separation efficiency, but it is difficult to simultaneously improve crystallinity and specific surface area; (3) to obtain special structural shapes (such as 0D, 1D, 2D, and 3D materials), as different dimensions have diverse characteristics. Thus, directional design can improve the performance of the materials.
In the study of SnWO4 for photocatalysis, there have been many attempts to obtain improved properties by adjusting the morphologies of the substrate materials. Zhu et al. obtained flower-like α-SnWO4 powders under neutral conditions with a DTAB-assisted hydrothermal method, degrading 95% of methyl orange (MO) within 80 min [33]. Want et al. also discussed the solvent-dependent morphology of α-SnWO4 powders [35], and Liu et al. synthesized nanostrips and nanosheets by changing the water/ethylene glycol ratio through a solvothermal method [34]. Meanwhile, the layered multi-hollow spherical α-SnWO4 powders [37] prepared by Zhu et al. and the nested nanostructure α-SnWO4 [32] prepared by Zhang et al. showed an improved catalytic performance after controlling their morphologies. The increased specific surface area enabled by morphology controlling exposes the active sites and shortens the length needed for photo-generated carriers to arrive at a surface. For a β-SnWO4 photocatalyst, Chen et al. prepared cubes and spike-cube shaped particles, with the latter showing strong photocatalytic activity [46]. Warmuth et al. formed tetrahedral β-SnWO4, which demonstrated better photodegradation activity than a β-SnWO4 material, with truncated octahedra and a spike-cube morphology (Figure 4a) [45]. Ungelenk et al. synthesized β-SnWO4 powders with a microemulsion method. The powders had a rhombohedral dodecahedron shape, and they could complete the degradation of methylene blue (MB) in 20 min [19]. Raj et al. also noted the better MO degradation performance of leaf-like β-SnWO4 compared with that of sphere-like and irregularly structured β-SnWO4 [36]. Alharthi et al. synthesized honeycomb-like β-SnWO4 with a hydrothermal method and calcined it at 700 °C, which enabled the photodegradation of rose bengal in 150 min [53]. For photoelectrochemical water splitting, it is difficult to control the morphology of the powder present on an electrode. Accordingly, Zhu et al. synthesized a porous α-SnWO4 film through the hydrothermal conversion of WO3 films [31], and they obtained a photocurrent density of 0.08 mA cm−2 at a potential of 1.23 VRHE. In contrast, topography optimized nails (Figure 4b) [27,29], nanosheets (Figure 4c) [56], and long-plates [28] have presented better PEC activity than α-SnWO4, with a powder stacked morphology because the array structures provide pathways for charge transfer, with less recombination.

3.2. Crystal Facet Engineering

During morphology regulation, the ratio of exposure facets may change as well [58]. It is noted that reaction activities vary for different facets [59,60]. Thus, charge transfer ability can be modified by controlling the anisotropic growth of crystals in a certain direction. The β-SnWO4 enclosed by (100) and (110) facets obtained the strong photocatalytic degradation of methylene blue [19]. Harb et al. found that the (001) facet of α-SnWO4 and the (100) facet of β-SnWO4 showed strong charge separation and transport capabilities via calculations with the HSE06 code [10]. They also discussed the (121), (210), (111), (200), and (040) exposed facets of α-SnWO4 using DFT, and the (210) and (121) facets were shown to perform oxygen evolution reaction due to the positive position of their valence band (Figure 5a) [61]. They also noted that the (001) facet had a high surface energy, but it may be thermodynamically less stable than the other five facets. Wang et al. discussed the oxygen evolution performance of α-SnWO4 (010) facets with different kinds of termination, and O-Sn termination showed better OER activity than did the others [62]. These DFT researchers have demonstrated that crystal facet engineering is another viable method for obtaining a good SnWO4 substrate material. Inspired by these projects, our group synthesized an α-SnWO4 array and added F ions to its precursor solution to increase the ratio of the (001) facet (Figure 5b). The facet-controlled film had a higher photocurrent than the uncontrolled film due to the better OER performance (Figure 5c) [29], and a ~1.9 times greater photocurrent was obtained in an unbiased PEC cell.

3.3. Doping Modification

Doping can change the position of an energy band, reduce the width of a band gap, and improve the efficiency of carrier separation and transfer, thus improving the catalytic performance of the materials. For example, Zn2+ doping was introduced into α-SnWO4 by Su et al. [44]. Because Zn and Sn have similar electronegativity values and suitable sizes, Zn2+ is used to replace Sn2+ in SnWO4 to form Sn1−xZnxWO4. This ensures that the Zn 4s and Zn 4p orbitals participate in the hybridization of the valence band and the conduction band, respectively, thus changing the position of the energy band and reducing the band gap. The authors also found that Zn2+ doping changed the morphology of the material, and the resulting Sn0.955Zn0.045WO4 could degrade nearly 90% of MO in 20 min. Zhu et al. introduced defects into α-SnWO4 through Bi3+ doping [37]. Unlike Zn2+ doping, Bi does not participate in the formation of energy band hybridization, but cation vacancies are formed due to changes in the charges. These defects form effective energy levels in the band gap which enhance light absorption, inhibit electron-hole pairing, and improve the photocatalytic properties of the material. Although the mechanisms of Zn2 and Bi3 doping are not exactly the same, both of them can improve the performance of SnWO4 by changing its morphology and band structure. At the same time, because β-SnWO4 has a wider band and a lower carrier separation efficiency than α-SnWO4, the doping of the two ions may lead to better performance improvements for β-SnWO4. In addition to these two kinds of hetero ions, there may be more suitable ions for SnWO4 modification (such as Mo and Co) that need to be further studied. In theory, Azofra et al. replaced Sn with Ge and substituted W with Mo in DFT calculations, and they obtained the enhanced orbital hybridization of the VBM/CBM electronic states, which amplified the amount of generated holes/electrons on top of the (110)/(100) facets [63]. However, these result have not been experimentally confirmed.

3.4. Multicomponent Composite

The multicomponent composite strategy includes coating a sedimentary protection layer and building heterojunction. Constructed multicomponent catalysts generally have the following advantages over single catalysts: (1) they expand the light absorption spectra, (2) they promote carrier separation, (3) they inhibit carrier recombination, and (4) they prevent photocorrosion.
In photocatalysis, the compositing of reduced graphene oxide (RGO) and β-SnWO4 can be achieved via microwave heating [12] and hydrothermal methods [50]. In such a composite, RGO, as a supporting material, provides a larger surface area and more active sites than β-SnWO4, thereby improving the specific surface area and catalytic activity of the material. At the same time, the high conductivity of RGO makes the electrons generated by β-SnWO4 move towards the RGO, while the holes remain inside β-SnWO4, which improves the carrier separation efficiency of the materials. The compositing of RGO and α-SnWO4 was reported by Huang et al. [43], and Wang et al. [41] combined hexagonal boron nitride (2D materials analogous to graphite) with α-SnWO4. Both groups improved the photocatalytic activity of α-SnWO4 for degrading methyl orange (MO) and tetracycline. In a composite of Ag-NPs and α-SnWO4 [38], the photo-absorption efficiency can be increased through the surface plasmon resonance (SPR) of Ag-NPs. Because Ag-NPs have lower Fermi levels than the bottom of the conduction band of α-SnWO4, the photoelectrons can migrate to Ag, increasing the efficiency of carrier separation. Moreover, Ag can more easily transfer electrons to a solution when it is in direct contact with the solution, which accelerates the transfer of interfacial carriers. The construction of heterojunctions is widely studied in SnWO4 material research. The formation of heterojunctions is mainly based on the combination of different energy band positions of different materials. Accordingly, photogenerated electrons are easier to transfer to materials with lower conduction bands, while photogenerated holes tend to transfer to materials with higher valence bands. It is possible to enhance the carrier separation efficiency of materials by selecting suitable materials for compositing. For example, the heterojunctions of α-SnWO4 and g-C3N4 were shown to effectively inhibit carrier recombination, thereby increasing the catalytic activity of the material [47]. SnWO4/ZnO [51], SnWO4/BiOBr [49], SnWO4/UiO-66/g-C3N4 ternary heterojunction [54], one dimensional ZnWO4@SnWO4 core-shell heterojunction [48], and SnS/α-SnWO4 [40] have also been reported. In addition, α-SnWO4 and SnO2 [42], along with β-SnWO4 [52], can form heterojunctions to improve the efficiency of carrier separation.
In photoelectrocatalysis, Kölbach and Schnell et al. deposited NiOx on α-SnWO4 to protect the substrate from photocorrosion [4], which improved material stability and maintained a stable current for sulfite oxidation at 1.23 V vs. RHE in 30 min. Furthermore, α-SnWO4 is susceptible to photo-corrosion and oxidation during photoelectrochemical water splitting, which results in a lower photocurrent value (<10 μA cm−2). However, the photocurrent of the material is greatly increased after protection by NiOx (~0.75 mA cm−2). Another study found that a thin oxide layer (SnO2) might form at the interface of α-SnWO4 and NiOx, which explains the reason for the decreasing photovoltage after the loading of NiOx [9]. Thus, the exploration of alternative techniques for loading protection layers, such as vacuum evaporation and atomic layer deposition, is recommended.

3.5. Other Techniques

In addition to the aforementioned approaches, photocatalysis and photoelectrocatalysis performance may be influenced by the external environment [64], as has been studied in recent years. Liu et al. discussed the PEC performance of SnWO4/Sn electrodes at different operating temperatures, and they found that higher photocurrents could be obtained at 70 °C (Figure 6a) [55]. Schnell studied the pH-dependent stability of α-SnWO4, and pH = 7 (Figure 6b) was suggested to be used for testing due to the formation of the surface oxide layer as a protection layer [65]. Besides, α-SnWO4, with higher crystallinity, was formed by Cottesman, presenting ~0.95 mA/cm2 after loading with NiOx for sulfite oxidation.

4. Conclusions and Outlook

In general, SnWO4 is considered a type of potential catalytic material for photocatalysis and photoelectrocatalysis, especially for water splitting, because of its optical properties and special band structure (which covers the oxidation and reduction potential of water). β-SnWO4 is always used in photocatalytic degradation due to the high reduction (oxidation) activity of its photo-generated electrons (holes), while α-SnWO4 is employed in both photocatalysis and photoelectrocatalysis. In recent years, many researchers have studied the application of SnWO4 in photocatalysis and photoelectrocatalysis, and they have improved the properties of materials by means of morphology control, doping, and multicomponent combinations. Compared with photocatalysis, photoelectrocatalysis has the advantage of discrete oxidation and reduction processes. This makes it easier to separate gaseous products, study reaction mechanisms and kinetics, and adjust reaction selectivity. Therefore, the application of α-SnWO4 in photoelectrocatalysis needs to be further explored. However, it is worth noting that the catalytic performance of α-SnWO4 and its applications in solar energy have not reached their expected values. For example, the highest reported experimental current for PEC water oxidation is only ~0.79 mA cm−2 at 1.23 VRHE, which is far from the theoretical value. Other problems include low efficiency and poor stability. To solve these problems, obtaining a high-performing substrate through morphology control, crystal surface control, and doping may prove to be an effective research route. Then, the PEC performance of α-SnWO4 can be further upgraded by constructing heterojunctions, depositing protective layers, and depositing cocatalysts. Of these methods, loading cocatalysts is the most promising because the catalysts can also act as protection layers. However, a suitable loading method to avoid oxidizing α-SnWO4 is required, and pinholes should be excluded to prevent α-SnWO4 from attaching to the electrolytes.

Author Contributions

W.Q.: writing—original draft and visualization; Y.L.: writing—review and editing, supervision, funding acquisition, and conceptualization. All authors have read and agreed to the published version of the manuscript.


This study was supported by the National Nature Science Foundation of China (51904356).

Data Availability Statement

Not applicable.


W.Q. and Y.L. appreciate GaoShuang He, Keke Wang, Wenzhang Li, and Jie Li’s suggestions on this paper.

Conflicts of Interest

The authors declare no conflict of interest.


  1. Fujishima, A.; Honda, K. Electrochemical Photolysis of Water at a Semiconductor Electrode. Nature 1972, 238, 37–38. [Google Scholar] [CrossRef] [PubMed]
  2. Tao, X.; Zhao, Y.; Wang, S.; Li, C.; Li, R. Recent advances and perspectives for solar-driven water splitting using particulate photocatalysts. Chem. Soc. Rev. 2022, 51, 3561–3608. [Google Scholar] [CrossRef] [PubMed]
  3. Cho, I.-S.; Kwak, C.H.; Kim, D.W.; Lee, S.; Hong, K.S. Photophysical, Photoelectrochemical, and Photocatalytic Properties of Novel SnWO4 Oxide Semiconductors with Narrow Band Gaps. J. Phys. Chem. C 2009, 113, 10647–10653. [Google Scholar] [CrossRef]
  4. Kölbach, M.; Pereira, I.J.; Harbauer, K.; Plate, P.; Höflich, K.; Berglund, S.P.; Friedrich, D.; van de Krol, R.; Abdi, F.F. Revealing the performance limiting factors in α-SnWO4 photoanodes for solar water splitting. Chem. Mater. 2018, 30, 8322–8331. [Google Scholar] [CrossRef] [Green Version]
  5. Jeitschko, W.; Sleight, A. Stannous tungstate: Properties, crystal structure and relationship to ferroelectric SbTaO4 type compounds. Acta Crystallogr. Sect. B Struct. Crystallogr. Cryst. Chem. 1974, 30, 2088–2094. [Google Scholar] [CrossRef]
  6. Jeitschko, W.; Sleight, A.W. Synthesis, properties and crystal structure of β-SnWO4. Acta Crystallogr. Sect. B Struct. Crystallogr. Cryst. Chem. 1972, 28, 3174–3178. [Google Scholar] [CrossRef]
  7. Ke, J.; Younis, M.A.; Kong, Y.; Zhou, H.; Liu, J.; Lei, L.; Hou, Y. Nanostructured Ternary Metal Tungstate-Based Photocatalysts for Environmental Purification and Solar Water Splitting: A Review. Nano-Micro Lett. 2018, 10, 69. [Google Scholar] [CrossRef] [Green Version]
  8. Gomes, E.O.; Gouveia, A.F.; Gracia, L.; Lobato, A.; Recio, J.M.; Andres, J. A Chemical-Pressure-Induced Phase Transition Controlled by Lone Electron Pair Activity. J. Phys. Chem. Lett. 2022, 13, 9883–9888. [Google Scholar] [CrossRef]
  9. Schnell, P.; Kolbach, M.; Schleuning, M.; Obata, K.; Irani, R.; Ahmet, I.Y.; Harb, M.; Starr, D.E.; van de Krol, R.; Abdi, F.F. Interfacial Oxide Formation Limits the Photovoltage of α-SnWO4/NiOx Photoanodes Prepared by Pulsed Laser Deposition. Adv. Energy Mater. 2021, 11, 2003183. [Google Scholar] [CrossRef]
  10. Harb, M.; Ziani, A.; Takanabe, K. Critical difference between optoelectronic properties of α- and β-SnWO4 semiconductors: A DFT/HSE06 and experimental investigation. Phys. Status Solidi B 2016, 253, 1115–1119. [Google Scholar] [CrossRef]
  11. Kuzmin, A.; Anspoks, A.; Kalinko, A.; Timoshenko, J.; Kalendarev, R. Extended x-ray absorption fine structure spectroscopy and first-principles study of SnWO4. Phys. Scr. 2014, 89, 044005. [Google Scholar] [CrossRef]
  12. Thangavel, S.; Venugopal, G.; Kim, S.-J. Enhanced photocatalytic efficacy of organic dyes using β-tin tungstate–reduced graphene oxide nanocomposites. Mater. Chem. Phys. 2014, 145, 108–115. [Google Scholar] [CrossRef]
  13. Alexei, K.; Andris, A.; Aleksandr, K.; Janis, T.; Robert, K.; Lucie, N.; François, B.; Tetsuo, I.; Pascale, R. Pressure-induced insulator-to-metal transition in α-SnWO4. J. Phys. Conf. Ser. 2016, 712, 012122. [Google Scholar]
  14. Kuzmin, A.; Zubkins, M.; Kalendarev, R. Preparation and Characterization of Tin Tungstate Thin Films. Ferroelectrics 2015, 484, 49–54. [Google Scholar] [CrossRef]
  15. Ziani, A.; Harb, M.; Noureldine, D.; Takanabe, K. UV-Vis optoelectronic properties of α-SnWO4: A comparative experimental and density functional theory based study. APL Mater. 2015, 3, 096101. [Google Scholar] [CrossRef] [Green Version]
  16. Stoltzfus, M.W.; Woodward, P.M.; Seshadri, R.; Klepeis, J.-H.; Bursten, B. Structure and Bonding in SnWO4, PbWO4, and BiVO4:  Lone Pairs vs. Inert Pairs. Inorg. Chem. 2007, 46, 3839–3850. [Google Scholar] [CrossRef]
  17. Wojcik, J.; Calvayrac, F.; Goutenoire, F.; Mhadhbi, N.; Corbel, G.; Lacorre, P.; Bulou, A. Lattice Dynamics of β-SnWO4: Experimental and Ab Initio Calculations. J. Phys. Chem. C 2013, 117, 5301–5313. [Google Scholar] [CrossRef]
  18. Pavithra, N.S.; Patil, S.B.; Kumar, S.R.K.; Alharthi, F.A.; Nagaraju, G. Facile synthesis of nanocrystalline β-SnWO4: As a photocatalyst, biosensor and anode for Li-ion battery. SN Appl. Sci. 2019, 1, 1123. [Google Scholar] [CrossRef] [Green Version]
  19. Ungelenk, J.; Feldmann, C. Synthesis of faceted β-SnWO4 microcrystals with enhanced visible-light photocatalytic properties. Chem. Commun. 2012, 48, 7838–7840. [Google Scholar] [CrossRef]
  20. Huang, J.; Liu, H.; Zhong, J.; Li, J. Enhanced simulated sunlight-driven photocatalytic performance of SnWO4 prepared in the presence of cetyltrimethylammonium bromide. Environ. Prog. Sustain. Energy 2020, 39, e13314. [Google Scholar] [CrossRef]
  21. Alharthi, F.A.; Shashank, M.; Shashikanth, J.; Viswantha, R.; Alghamdi, A.A.; Algethami, J.; Alsaiari, M.A.; Jalalah, M.S.; Ganganagappa, N. Hydrothermal synthesis of α-SnWO4: Application to lithium-ion battery and photocatalytic activity. Ceram. Int. 2021, 47, 10242–10249. [Google Scholar] [CrossRef]
  22. Barros, M.M.P.; Almeida, K.C.; Silva, S.A.; Botelho, G. Synthesis and characterization of α-SnWO4 powders obtained by microwave-assisted hydrothermal method. Cerâmica 2022, 68, 236–241. [Google Scholar] [CrossRef]
  23. Kölbach, M.; Hempel, H.; Harbauer, K.; Schleuning, M.; Petsiuk, A.; Höflich, K.; Deinhart, V.; Friedrich, D.; Eichberger, R.; Abdi, F.F.; et al. Grain Boundaries Limit the Charge Carrier Transport in Pulsed Laser Deposited α-SnWO4 Thin Film Photoabsorbers. ACS Appl. Energy Mater. 2020, 3, 4320–4330. [Google Scholar] [CrossRef]
  24. Bozheyev, F.; Akinoglu, E.M.; Wu, L.; Lu, H.; Nemkayeva, R.; Xue, Y.; Jin, M.; Giersig, M. Band gap optimization of tin tungstate thin films for solar water oxidation. Int. J. Hydrogen Energy 2020, 45, 8676–8685. [Google Scholar] [CrossRef]
  25. Gottesman, R.; Peracchi, I.; Gerke, J.L.; Irani, R.; Abdi, F.F.; van de Krol, R. Shining a Hot Light on Emerging Photoabsorber Materials: The Power of Rapid Radiative Heating in Developing Oxide Thin-Film Photoelectrodes. ACS Energy Lett. 2022, 7, 514–522. [Google Scholar] [CrossRef]
  26. Zhu, S.; Liu, D.; Li, J.; Kuang, Y. Chemical Vapor Deposition of Crystalized Nanoscale α-SnWO4 Thin Films and Their Photoelectrocatalytic Properties. ACS Appl. Energy Mater. 2022, 5, 14372–14380. [Google Scholar] [CrossRef]
  27. Pyper, K.J.; Evans, T.C.; Bartlett, B.M. Synthesis of α-SnWO4 thin-film electrodes by hydrothermal conversion from crystalline WO3. Chin. Chem. Lett. 2015, 26, 474–478. [Google Scholar] [CrossRef]
  28. Qiu, W.; Zhang, Y.; He, G.; Chen, L.; Wang, K.; Wang, Q.; Li, W.; Liu, Y.; Li, J. Two-Dimensional Long-Plate SnWO4 Photoanode Exposed Active Facets for Enhanced Solar Water Splitting. ACS Appl. Energy Mater. 2022, 5, 11732–11739. [Google Scholar] [CrossRef]
  29. Liu, Y.; Qiu, W.; He, G.; Wang, K.; Wang, Y.; Chen, L.; Wu, Q.; Li, W.; Li, J. Nail-like α-SnWO4 Array Film with Increased Reactive Facets for Photoelectrochemical Water Splitting. J. Phys. Chem. C 2022, 126, 15596–15605. [Google Scholar] [CrossRef]
  30. Mirsadeghi, S.; Zandavar, H.; Tooski, H.F.; Rahimi, M.; Sohouli, E.; Rahimi-Nasrabadi, M.; Ganjali, M.R.; Pourmortazavi, S.M. Rapid photodegradation and detection of zolpidem over β-SnWO4 and α-SnWO4 nanoparticles: Optimization and mechanism. Environ. Sci. Pollut. Res. 2020, 28, 5430–5442. [Google Scholar] [CrossRef]
  31. Zhu, Z.; Sarker, P.; Zhao, C.; Zhou, L.; Grimm, R.L.; Huda, M.N.; Rao, P.M. Photoelectrochemical Properties and Behavior of α-SnWO4 Photoanodes Synthesized by Hydrothermal Conversion of WO3 Films. ACS Appl. Mater. Interfaces 2017, 9, 1459–1470. [Google Scholar] [CrossRef] [PubMed]
  32. Zhang, X.; You, X.; Wang, X.; Yu, C.; Xu, L.; Wang, C.; Song, Y.; Zhang, F. Nest-like α-SnWO4 nanostructures assembled by nanowires: Facile synthesis and their superior photocatalytic performance. J. Alloys Compd. 2019, 802, 502–510. [Google Scholar] [CrossRef]
  33. Zhu, G.; Que, W.; Zhang, J.; Zhong, P. Photocatalytic activity of SnWO4 and SnW3O9 nanostructures prepared by a surfactant-assisted hydrothermal process. Mater. Sci. Eng. B 2011, 176, 1448–1455. [Google Scholar] [CrossRef]
  34. Liu, X.; Liang, B.; Yang, J.; Li, W. Solvent effect on morphological evolution and photocatalytic property of α-SnWO4. J. Taiwan Inst. Chem. Eng. 2019, 95, 575–582. [Google Scholar] [CrossRef]
  35. Wang, Q.L.; Li, H.B.; Jiang, H.Y.; Ding, S.T.; Song, Z.W.; Shi, J.S. Effect of solvent on α-SnWO4 photocatalyst for degradation of methyl orange under visible light irradiation. Adv. Perform. Mater. 2015, 30, 288–293. [Google Scholar] [CrossRef]
  36. Raj, A.T.; Thangavel, S.; Rose, A.; Jipsa, C.V.; Jose, M.; Nallamuthu, G.; Kim, S.-J.; Venugopal, G. Influence of Morphology and Common Oxidants on the Photocatalytic Property of β-SnWO4 Nanoparticles. J. Nanosci. Nanotechnol. 2016, 16, 2541–2547. [Google Scholar] [CrossRef]
  37. Zhu, Z.; Tian, H.; Zhang, M.; Liang, B.; Li, W. Preparation of α-SnWO4 hierarchical spheres by Bi3+-doping and their enhanced photocatalytic activity under visible light. Ceram. Int. 2016, 42, 14743–14748. [Google Scholar] [CrossRef]
  38. Liu, X.; Liang, B.; Zhang, M.; Long, Y.; Li, W. Enhanced photocatalytic properties of α-SnWO4 nanosheets modified by Ag nanoparticles. J. Colloid Interface Sci. 2017, 490, 46–52. [Google Scholar] [CrossRef]
  39. Wang, Y.; Zhou, S.; Zhao, G.; Li, C.; Liu, L.; Jiao, F. Fabrication of SnWO4/ZnFe-layered double hydroxide composites with enhanced photocatalytic degradation of methyl orange. J. Mater. Sci.-Mater. Electron. 2020, 31, 12269–12281. [Google Scholar] [CrossRef]
  40. Liu, X.; Liang, B.; Li, W. In situ decoration of SnS quantum dots on the α-SnWO4 nanosheets for superior visible-light photocatalytic performance. Appl. Surf. Sci. 2020, 531, 147379. [Google Scholar] [CrossRef]
  41. Wang, J.; Yan, H.; Long, Y.; Li, W. Enhanced photocatalytic property of α-SnWO4 nanoplates by h-BN decorating. J. Mater. Sci. Mater. Electron. 2021, 32, 21858–21868. [Google Scholar] [CrossRef]
  42. Yao, S.; Zhang, M.; Di, J.; Wang, Z.; Long, Y.; Li, W. Preparation of α-SnWO4/SnO2 heterostructure with enhanced visible-light-driven photocatalytic activity. Appl. Surf. Sci. 2015, 357, 1528–1535. [Google Scholar] [CrossRef]
  43. Huang, R.K.; Ge, H.; Lin, X.J.; Guo, Y.L.; Yuan, R.S.; Fu, X.Z.; Li, Z.H. Facile one-pot preparation of α-SnWO4/reduced graphene oxide (RGO) nanocomposite with improved visible light photocatalytic activity and anode performance for Li-ion batteries. RSC Adv. 2013, 3, 1235–1242. [Google Scholar] [CrossRef]
  44. Su, Y.G.; Hou, L.C.; Du, C.F.; Peng, L.M.; Guan, K.; Wang, X.J. Rapid synthesis of Zn2+ doped SnWO4 nanowires with the aim of exploring doping effects on highly enhanced visible photocatalytic activities. RSC Adv. 2012, 2, 6266–6273. [Google Scholar] [CrossRef]
  45. Warmuth, L.; Feldmann, C. β-SnWO4 with Morphology-Controlled Synthesis and Facet-Depending Photocatalysis. ACS Omega 2019, 4, 13400–13407. [Google Scholar] [CrossRef] [Green Version]
  46. Chen, Y.-C.; Lin, Y.-G.; Hsu, L.-C.; Tarasov, A.; Chen, P.-T.; Hayashi, M.; Ungelenk, J.; Hsu, Y.-K.; Feldmann, C. β-SnWO4 Photocatalyst with Controlled Morphological Transition of Cubes to Spikecubes. ACS Catal. 2016, 6, 2357–2367. [Google Scholar] [CrossRef]
  47. Liang, Q.; Jin, J.; Liu, C.; Xu, S.; Yao, C.; Chen, Z.; Li, Z. Hydrothermal fabrication of α-SnWO4/g-C3N4 heterostructure with enhanced visible-light photocatalytic activity. J. Mater. Sci. Mater. Electron. 2017, 28, 11279–11283. [Google Scholar] [CrossRef]
  48. Zhuang, H.; Xu, W.; Lin, L.; Huang, M.; Xu, M.; Chen, S.; Cai, Z. Construction of one dimensional ZnWO4@SnWO4 core-shell heterostructure for boosted photocatalytic performance. J. Mater. Sci. Technol. 2019, 35, 2312–2318. [Google Scholar] [CrossRef]
  49. Chowdhury, A.P.; Shambharkar, B.H. Fabrication and characterization of BiOBr-SnWO4 heterojunction nanocomposites with boosted photodegradation capability. Chem. Eng. J. Adv. 2020, 4, 100040. [Google Scholar] [CrossRef]
  50. Alharthi, F.A.; Alsaiari, M.A.; Jalalah, M.S.; Shashank, M.; Shashikanth; Alghamdi, A.A.; Algethami, J.S.; Ganganagappa, N. Combustion synthesis of β-SnWO4-rGO: Anode material for Li-ion battery and photocatalytic dye degradation. Ceram. Int. 2021, 47, 10291–10300. [Google Scholar] [CrossRef]
  51. Elviera; Yulizar, Y.; Apriandanu, D.O.B.; Surya, R.M. Fabrication of novel SnWO4/ZnO using Muntingia calabura L. leaf extract with enhanced photocatalytic methylene blue degradation under visible light irradiation. Ceram. Int. 2022, 48, 3564–3577. [Google Scholar] [CrossRef]
  52. Ungelenk, J.; Feldmann, C. Nanoscale β-Sn1-nWO4·nα-Sn-A highly efficient photocatalyst for daylight-driven degradation of organic dyes and its real “green” synthesis. Appl. Catal. B-Environ. 2011, 102, 515–520. [Google Scholar] [CrossRef]
  53. Alharthi, F.A.; AlFawaz, A.; Ahmad, N. Photocatalytic degradation of anionic dye using well-crystalline SnWO4 polyoxometalate. Phys. Scr. 2022, 97, 085813. [Google Scholar] [CrossRef]
  54. Wei, Q.; Xiong, S.; Li, W.; Jin, C.; Chen, Y.; Hou, L.; Wu, Z.; Pan, Z.; He, Q.; Wang, Y.; et al. Double Z-scheme system of α-SnWO4/UiO-66(NH2)/g-C3N4 ternary heterojunction with enhanced photocatalytic performance for ibuprofen degradation and H2 evolution. J. Alloys Compd. 2021, 885, 160984. [Google Scholar] [CrossRef]
  55. Liu, D.; Chen, X.; Qiao, Y.; Zhou, Y.; Kuang, Y. Awakening the Photoelectrochemical Activity of α-SnWO4 Photoanodes with extraordinary Crystallinity Induced by Reductive Annealing. Adv. Energy Sustain. Res. 2021, 3, 2100146. [Google Scholar] [CrossRef]
  56. He, G.; Li, W.; Qiu, W.; Xu, C.; Wang, K.; Chen, L.; Wang, Y.; Liu, Y.; Li, J. Constructing a Two-Dimensional SnWO4 Nanosheet Array Film for Enhanced Photoelectrochemical Performance. ACS Appl. Energy Mater. 2022, 5, 11883–11891. [Google Scholar] [CrossRef]
  57. Wu, H.; Tan, H.L.; Toe, C.Y.; Scott, J.; Wang, L.; Amal, R.; Ng, Y.H. Photocatalytic and Photoelectrochemical Systems: Similarities and Differences. Adv. Mater. 2019, 32, 1904717. [Google Scholar] [CrossRef] [PubMed]
  58. Liu, Y.; Wygant, B.R.; Kawashima, K.; Mabayoje, O.; Hong, T.E.; Lee, S.-G.; Lin, J.; Kim, J.-H.; Yubuta, K.; Li, W.; et al. Facet effect on the photoelectrochemical performance of a WO3/BiVO4 heterojunction photoanode. Appl. Catal. B 2019, 245, 227–239. [Google Scholar] [CrossRef]
  59. Chen, L.; Li, W.; Qiu, W.; He, G.; Wang, K.; Liu, Y.; Wu, Q.; Li, J. Oriented CuWO4 Films for Improved Photoelectrochemical Water Splitting. ACS Appl. Energy Mater. 2022, 14, 47737–47746. [Google Scholar] [CrossRef]
  60. Liu, C.; Chen, L.; Su, X.; Chen, S.; Zhang, J.; Yang, H.; Pei, Y. Activating a TiO2/BiVO4 Film for Photoelectrochemical Water Splitting by Constructing a Heterojunction Interface with a Uniform Crystal Plane Orientation. ACS Appl. Energy Mater. 2022, 14, 2316–2325. [Google Scholar] [CrossRef]
  61. Harb, M.; Cavallo, L.; Basset, J.-M. Remarkable Influence of α-SnWO4 Exposed Facets on Their Photocatalytic Performance for H2 and O2 Evolution Reactions. J. Phys. Chem. C 2020, 124, 18684–18689. [Google Scholar] [CrossRef]
  62. Wang, W.; Wu, Y.; Chen, D.-L.; Liu, H.; Xu, M.; Liu, X.; Xin, L. The surface reconstruction induced enhancement of the oxygen evolution reaction on α-SnWO4 (010) based on a density functional theory study. Phys. Chem. Chem. Phys. 2022, 24, 19382–19392. [Google Scholar] [CrossRef] [PubMed]
  63. Azofra, L.M.; Cavallo, L.; Basset, J.-M.; Harb, M. Need for Rationally Designed SnWO4 Photo(electro)catalysts to Overcome the Performance Limitations for O2 and H2 Evolution Reactions. J. Phys. Chem. C 2021, 125, 8488–8496. [Google Scholar] [CrossRef]
  64. Liu, Y.; Chen, L.; Zhu, X.; Qiu, H.; Wang, K.; Li, W.; Cao, S.; Zhang, T.; Cai, Y.; Wu, Q.; et al. Effects of operating temperature on photoelectrochemical performance of CuWO4 film photoanode. J. Electroanal. Chem. 2022, 924, 116859. [Google Scholar] [CrossRef]
  65. Schnell, P.; Dela Cruz, J.M.C.M.; Kölbach, M.; van de Krol, R.; Abdi, F.F. pH-Dependent Stability of α-SnWO4 Photoelectrodes. Chem. Mater. 2022, 34, 1590–1598. [Google Scholar] [CrossRef]
Figure 1. Crystal structures of SnWO4 polymorphs: (a) α-SnWO4 (orthorhombic); (b) β-SnWO4 (cubic).
Figure 1. Crystal structures of SnWO4 polymorphs: (a) α-SnWO4 (orthorhombic); (b) β-SnWO4 (cubic).
Energies 15 09194 g001
Figure 2. Partial density states of (a) α-SnWO4 and (b) β-SnWO4 [3].
Figure 2. Partial density states of (a) α-SnWO4 and (b) β-SnWO4 [3].
Energies 15 09194 g002
Figure 3. Schematic for in situ conversion from a rod-like WO3 array to a rod-like SnWO4 [28].
Figure 3. Schematic for in situ conversion from a rod-like WO3 array to a rod-like SnWO4 [28].
Energies 15 09194 g003
Figure 4. (a) Different shapes of β-SnWO4 [45]; α-SnWO4 with (b) dense nanorods [27] and (c) nanosheet [56] morphology.
Figure 4. (a) Different shapes of β-SnWO4 [45]; α-SnWO4 with (b) dense nanorods [27] and (c) nanosheet [56] morphology.
Energies 15 09194 g004
Figure 5. (a) VBM and CBM energy levels for the optimized (121)−, (210)−, (111)−, (200)−, (040)−, (110), and (001) oriented α-SnWO4 slabs [61,63]; (b) surface free energy (γ) of facets before and after the termination with F and Cl atoms; (c) free-energy profiles of OER on (001)−, (010)−, (100)−, and (121) slabs at 0 V (the * means adsorbed state) [29].
Figure 5. (a) VBM and CBM energy levels for the optimized (121)−, (210)−, (111)−, (200)−, (040)−, (110), and (001) oriented α-SnWO4 slabs [61,63]; (b) surface free energy (γ) of facets before and after the termination with F and Cl atoms; (c) free-energy profiles of OER on (001)−, (010)−, (100)−, and (121) slabs at 0 V (the * means adsorbed state) [29].
Energies 15 09194 g005
Figure 6. (a) LSV curves of the SnWO4 (500 °C H2) photoanode measured in KOH/H3BO3 buffer (pH = 9) with 0.2 M Na2SO3 at different temperatures under the chopped 455 nm LED illumination [55]; (b) the concentrations of Sn and W dissolved from α-SnWO4 films after photoelectrochemically treated at various pH levels at a potential of 1.23 V vs. RHE, for a total of 1 h [65].
Figure 6. (a) LSV curves of the SnWO4 (500 °C H2) photoanode measured in KOH/H3BO3 buffer (pH = 9) with 0.2 M Na2SO3 at different temperatures under the chopped 455 nm LED illumination [55]; (b) the concentrations of Sn and W dissolved from α-SnWO4 films after photoelectrochemically treated at various pH levels at a potential of 1.23 V vs. RHE, for a total of 1 h [65].
Energies 15 09194 g006
Table 1. Recently reported SnWO4-based materials for photocatalysis.
Table 1. Recently reported SnWO4-based materials for photocatalysis.
Type of CatalystOrganic PollutantLightDegradation EfficiencyRef.
Nest-like α-SnWO4methyl orange (MO)300 W Xe arc lamp > 420 nm96.1% (60 min)[32]
Flower-like α-SnWO4MO300 W tungsten-halogen lamp > 420 nm95% (80 min)[33]
α-SnWO4 nanostrips + small nanosheetsMO500 W Xe lamp90.4% (30 min)[34]
α-SnWO4 synthesized with different solventsMO300 W Xe lamp > 420 nm98% (80 min)[35]
leaf-like β-SnWO4MO250 W tungsten-halogen lamp60% (2 h)[36]
Bi3+-doped α-SnWO4MO500 W Xe lamp > 420 nm95% (2 h)[37]
α-SnWO4/Ag-NPsMO500 W Xe lamp > 420 nm97% (70 min)[38]
α-SnWO4/ZnFe-LDHMO500 W Xe lamp95.1% (40 min)[39]
SnS/α-SnWO4MO500 W Xe lamp95.6% (90 min)[40]
CTAB-α-SnWO4MO500 W Xe lamp58.7% (30 min)[20]
h-BN/α-SnWO4MO300 W Xe lamp > 420 nm94.7% (90 min)[41]
α-SnWO4/SnO2MO500 W Xe lamp > 420 nm97% (40 min)[42]
β-SnWO4-GOMOtungsten-halogen lamp > 420 nm90% (25 min)[12]
α-SnWO4-GOMO300 W tungsten-halogen lamp > 420 nm41.2% (6 h)[43]
Zn2+ doped α-SnWO4 nanowiresMO300 W Hg lamp > 420 nm~100% (90 min) [44]
β-SnWO4 with different morphologyrhodamine B (RhB)AM 1.5 G solar light (100 mW cm−2)~22% (2 h)[45]
Cube β-SnWO4RhB8 W UV-lamp with a monowavelength of 366 nmTOF:1.14[46]
Spike-cube β-SnWO4RhB8 W UV-lamp with a monowavelength of 366 nmTOF:2.77[46]
SnS/α-SnWO4RhB500 W Xe lamp97.62% (2 h)[40]
α-SnWO4/g-C3N4RhB500 W Xe arc lamp > 420 nm91% (80 min)[47]
1D ZnWO4@β-SnWO4RhB300 W Xe lamp > 420 nm~100% (2 h)[48]
β-SnWO4-GORhBunder visible light91% (25 min)[12]
α-SnWO4RhB100 W tungsten-halogen lamp > 420 nm~82% (4 h)[3]
β-SnWO4RhB100 W tungsten-halogen lamp > 420 nm~97% (4 h)[3]
BiOBr/α-SnWO4RhBsunlight97.9% (1 h)[49]
spike-cube β-SnWO4methylene blue (MB)8 W UV-lamp with a monowavelength of 366 nmTOF:2.65[43]
β-SnWO4-rGO nanocompositeMBtungsten-halogen lamp > 420 nm94% (2 h)[50]
β-SnWO4/ZnOMB70 W sodium lamps82.9% (2 h)[51]
β-SnWO4 truncated rhombic dodecahedronsMB150 W halogen lamp100% (20 min)[19]
β-Sn1−nWO4·nα-SnMBhalogen bulb (3300 K)~90% (1 h)[52]
h-BN/α-SnWO4tetracycline (TC)300 W Xe lamp > 420 nm82.2% (4 h)[41]
SnS/α-SnWO4TC500 W Xe lamp57.0% (3 h)[40]
β-SnWO4-rGO nanocompositerose bengal (RB)tungsten-halogen lamp > 420 nm98% (2 h)[50]
β-SnWO4 NPsRB300 W tungsten bulb94.6% (2.5 h)[53]
α-SnWO4/UiO-66(NH2)/g-C3N4ibuprofen (IPF)high pressure Xe lamp source simulated sunlight95.5% (2 h)[54]
β-Sn1−nWO4·nα-Snbasic green 4 (BG)halogen bulb (3300 K)~63% (1 h)[52]
BiOBr/α-SnWO4BGsunlight95.5% (45 min)[49]
β-Sn1−nWO4·nα-Snmethyl red (MR)halogen bulb (3300 K)~71% (1 h)[52]
Table 2. Recent report on the performance of α-SnWO4 based photoanodes in PEC water splitting.
Table 2. Recent report on the performance of α-SnWO4 based photoanodes in PEC water splitting.
PhotoanodePhotocurrent Density (at 1.23 V vs. RHE)ElectrolyteRef.
α-SnWO4 nanowires0.032 mA cm−20.1 M KPi buffer
(pH ≈ 5)
α-SnWO4 porous nanostructure0.080 mA cm−20.5 M KPi buffer
(pH ≈ 7)
α-SnWO4 nanocrystalline particles~0.750 mA cm−20.5 M KPi buffer and 0.5 M Na2SO3
(pH ≈ 7)
α-SnWO4 microcrystalline particles0.375 mA cm−20.5 M Na2SO4 (pH ≈ 7)[24]
α-SnWO4 coral-like morphology0.420 mA cm−2KOH/H3BO3 buffer and 0.2 M Na2SO3 (pH ≈ 9)[55]
2D nanosheets α-SnWO4 0.411 mA cm−20.2 M KPi buffer
(pH ≈ 7)
Nail-like α-SnWO40.300 mA cm−20.2 M KPi buffer
(pH ≈ 7)
2D long-plate α-SnWO40.790 mA cm−20.2 M KPi buffer
(pH ≈ 7)
NiOx coated RTP-α-SnWO40.950 mA cm−20.5 M KPi buffer with 0.5 M Na2SO3
(pH ≈ 7)
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Qiu, W.; Liu, Y. Stannous Tungstate Semiconductor for Photocatalytic Degradation and Photoelectrochemical Water Splitting: A Review. Energies 2022, 15, 9194.

AMA Style

Qiu W, Liu Y. Stannous Tungstate Semiconductor for Photocatalytic Degradation and Photoelectrochemical Water Splitting: A Review. Energies. 2022; 15(23):9194.

Chicago/Turabian Style

Qiu, Weixin, and Yang Liu. 2022. "Stannous Tungstate Semiconductor for Photocatalytic Degradation and Photoelectrochemical Water Splitting: A Review" Energies 15, no. 23: 9194.

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop