Visible-Light Photocatalysis for Sustainable Environmental Remediation

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Photocatalysis".

Deadline for manuscript submissions: closed (31 January 2024) | Viewed by 7530

Special Issue Editors


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Guest Editor
School of Environmental and Chemical Engineering, Foshan University, Foshan 528000, China
Interests: photocatalysis; plasma catalysis; VOCs; wastewater treatment; carbon-based materials; advanced oxidation
Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China
Interests: photocatalysis; adsorption; nanomaterials; heterostructures; green chemistry

Special Issue Information

Dear Colleagues,

Since the breakthrough of photoelectrochemical decomposition of water by TiO2 was firstly achieved in the year 1972, semiconductor-based photocatalysis has aroused a lot of interest over a wide range of applications in the fields of the environment (e.g., pollutant decomposition, CO2 conversion) and energy (e.g., H2 production). The development of photocatalysts with high reactivity under visible light has become the most often explored topic because of its possibility to promote the technology to industrially large-scale practice. In recent decades, numerous photocatalysts have been prepared and modified to be visible-light-responsive, including doped metal oxides (TiO2, ZnO, etc.), bismuth-based compounds (BiVO4, Bi2O3, BiOI, etc.), sulfide-based compounds (CdS, ZnIn2S4, etc.), g-C3N4, and their heterostructural composites. Alongside reasonable band positions engineered for conceivable visible light absorbance, a productive photocatalyst ought to likewise have 1) an improved charge partition for a high quantum proficiency, 2) compelling interfacial collaborations to obtain cozy contact between target molecules and photocatalyst, toward a complete transformation of reactants, and 3) improved adsorption ability for accumulation and decomposition of low-concentration pollutants.

This Special Issue entitled “Visible-Light Photocatalysis for Sustainable Environmental Remediation” aims to cover the novel synthesis and characterization of visible-light-responsive materials and their composites for environmentally sustainable applications. We welcome authors to contribute articles and reviews exploring the exceptional accentuation of visible-light photocatalysts for water remediation, degradation of environmental pollutants, N2 fixation, CO2 reduction, hydrogen evolution, etc.

Dr. Weicheng Xu
Dr. Zhang Liu
Guest Editors

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Keywords

  • visible-light photocatalysis
  • pollutant degradation
  • CO2 reduction
  • wastewater treatment
  • environmental remediation

Published Papers (5 papers)

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Research

21 pages, 3415 KiB  
Article
Impact of Copper(II)-Imidazole Complex Modification on Polycrystalline TiO2: Insights into Formation, Characterization, and Photocatalytic Performance
by Ganeshraja Ayyakannu Sundaram, Rajkumar Kanniah, Krishnamoorthy Anbalagan, Kaviyarasan Kulandaivelu and Héctor Valdés
Catalysts 2024, 14(3), 169; https://doi.org/10.3390/catal14030169 - 26 Feb 2024
Cited by 2 | Viewed by 1183
Abstract
Micrometer-sized polycrystalline anatase particles are widely used in materials and life sciences, serving as essential components in photocatalytic materials. The ability to tailor their composition, shape, morphology, and functionality holds significant importance. In this study, we identified and examined the non-destructive route of [...] Read more.
Micrometer-sized polycrystalline anatase particles are widely used in materials and life sciences, serving as essential components in photocatalytic materials. The ability to tailor their composition, shape, morphology, and functionality holds significant importance. In this study, we identified and examined the non-destructive route of Copper(II) implantation at the surface of polycrystalline TiO2. The [Cu(en)(Im)2]2+ complex ion demonstrated a remarkable affinity to concentrate and bind with the semiconductor’s surface, such as anatase, forming a surface-bound adduct: ≡TiO2 + [Cu(en)(Im)2]2+ → ≡TiO2//[Cu(en)(Im)2]2+. The misalignment of Fermi levels in TiO2//[Cu(en)(Im)2]2+ triggered electron transfer, leading to the reduction of the metal center, releasing Copper(I) in the process. Although less efficient, the released Copper(I) encountered a highly favorable environment, resulting in the formation of the surface complex TiO2:CuIIsc. The implanted Cu(I) was converted back into Cu(II) due to re-oxidation by dissolved oxygen. The penetration of the metal ion into the surface level of the polycrystalline TiO2 lattice was influenced by surface residual forces, making surface grafting of the Cu(II) ion inevitable due to surface chemistry. FTIR, UV–vis, Raman, XRD, EPR, and surface morphological (SEM, EDAX, and HRTEM) analyses identified the typical surface grafting of the Cu(II) cluster complex on the anatase surface matrix. Moreover, the XRD results also showed the formation of an impure phase. The TiO2 polycrystalline materials, modified by the incorporation of copper complexes, demonstrated an enhanced visible-light photocatalytic capability in the degradation of Rhodamine B dye in aqueous solutions. This modification significantly improved the efficiency of the photocatalytic process, expanding the applicability of TiO2 to visible light wavelengths. These studies open up the possibility of using copper complexes grafted on metal oxide surfaces for visible-light active photocatalytic applications. Moreover, this investigation not only showcases the improved visible-light photocatalytic behavior of copper-modified TiO2 polycrystalline materials, but also underscores the broader implications of this improvement in the advancement of sustainable and efficient water treatment technologies. Full article
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15 pages, 12884 KiB  
Article
Photocatalytic Degradation of Tetracycline Hydrochloride by Mn/g-C3N4/BiPO4 and Ti/g-C3N4/BiPO4 Composites: Reactivity and Mechanism
by Wei Qian, Yi Fang, Hui Liu, Yili Deng, Yingying Li, Yongzheng Zhang, Zenghui Diao and Mingyu Li
Catalysts 2023, 13(11), 1398; https://doi.org/10.3390/catal13111398 - 26 Oct 2023
Cited by 1 | Viewed by 1184
Abstract
The environmental pollution caused by antibiotics is becoming more serious. In this study, the Mn/BiPO4/g-C3N4 composite (Mn-BPC) and the Ti/g-C3N4/BiPO4 composite (Ti-BPC) were prepared by hydrothermal reaction method and solvent method, respectively, and [...] Read more.
The environmental pollution caused by antibiotics is becoming more serious. In this study, the Mn/BiPO4/g-C3N4 composite (Mn-BPC) and the Ti/g-C3N4/BiPO4 composite (Ti-BPC) were prepared by hydrothermal reaction method and solvent method, respectively, and applied to the degradation of tetracycline (TC) in an aqueous environment. The XRD and HRTEM results showed that these materials had the crystalline rod-like structure of BiPO4 and abundant carbon, nitrogen and carbon–oxygen surface functional groups. The degradation of TC by Ti-BPC and Mn-BPC were nearly 92% and 79%, respectively. The degradation processes of TC were well consistent with the pseudo-second-order kinetics model and R2 values were closer to 1. The trapping experiment showed that electron holes (h+) were the main reactive species for the degradation of tetracycline, OH· and O2 also have certain effects. Also, the possible photocatalytic degradation mechanism of Ti-BPC and Mn-BPC composites was thereby proposed. TC was firstly adsorbed on the surface of catalysts, and subsequently degraded by reactive species such as h+, OH· and O2 generated under visible light excitation. This study shows that the Ti-BPC and Mn-BPC photocatalysts have great potential in antibiotic degradation and can provide new ideas for antibiotic removal in aqueous environments. Full article
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15 pages, 12327 KiB  
Article
Visible-Light-Driven Peroxymonosulfate Activation for Accelerating Tetracycline Removal Using Co-TiO2 Nanospheres
by Xueding Jiang, Jianghong Li, Jiesen Li, Weicheng Xu and Zhang Liu
Catalysts 2023, 13(5), 836; https://doi.org/10.3390/catal13050836 - 3 May 2023
Cited by 1 | Viewed by 1641
Abstract
Heterogeneous catalysts have been widely used for peroxymonosulfate (PMS) activation to remove persistent contaminants in water. This study successfully prepared cobalt-doped TiO2 using a simple two-step approach for activating PMS to remove tetracycline (TC). The batch experiments showed complete TC degradation within [...] Read more.
Heterogeneous catalysts have been widely used for peroxymonosulfate (PMS) activation to remove persistent contaminants in water. This study successfully prepared cobalt-doped TiO2 using a simple two-step approach for activating PMS to remove tetracycline (TC). The batch experiments showed complete TC degradation within 25 min caused by Co-TiO2 (0.1 g/L) activation of PMS (1 mM) under visible light. The system also demonstrated excellent catalytic efficiency in various water environments, such as artificial seawater, tap water, and wastewater. According to the radical capture tests and electron spin resonance analysis, the contribution of active species involved in the degradation of TC with the Vis/Co-TiO2/PMS system were in the following order: 1O2> SO4•−> O2•−> •OH. The possible TC degradation pathway was proposed using intermediate identification and Fukui function calculation. This study provides a promising method toward organic pollutants degradation and provides a novel perspective on the rational design of competent and stable catalysts. Full article
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12 pages, 2026 KiB  
Article
Controlled Synthesis of Ag-SnO2/α-Fe2O3 Nanocomposites for Improving Visible-Light Catalytic Activities of Pollutant Degradation and CO2 Reduction
by Wajid Ali, Zhijun Li, Linlu Bai, Muhammad Zaka Ansar, Amir Zada, Yang Qu, Shabana Shaheen and Liqiang Jing
Catalysts 2023, 13(4), 696; https://doi.org/10.3390/catal13040696 - 4 Apr 2023
Cited by 6 | Viewed by 1378
Abstract
The key to developing highly active α-Fe2O3-based photocatalysts is to improve the charge separation and efficiently utilize the electrons with sufficient thermodynamic energy. Herein, α-Fe2O3 nanosheets (FO) were synthesized using a metal-ion-intervened hydrothermal method and then [...] Read more.
The key to developing highly active α-Fe2O3-based photocatalysts is to improve the charge separation and efficiently utilize the electrons with sufficient thermodynamic energy. Herein, α-Fe2O3 nanosheets (FO) were synthesized using a metal-ion-intervened hydrothermal method and then coupled with SnO2 nanosheets (SO) to obtain SO/FO nanocomposites. Subsequently, nanosized Ag was selectively loaded on SO using the photo-deposition method to result in the ternary Ag-SO/FO nanocomposites. The optimal nanocomposite could realize the efficient aerobic degradation of 2,4-dichlorophenol as a representative organic pollutant under visible-light irradiation (>420 nm), exhibiting nearly six-fold degradation rates of that for FO. Additionally, the Ag-SO/FO photocatalyst is also applicable to the visible-light degradation of other organic pollutants and even CO2 reduction. By using steady-state surface photovoltage spectroscopy, fluorescence spectroscopy, and electrochemical methods, the photoactivity enhancement of Ag-SO/FO is principally attributed to the improved charge separation by introducing SO as an electron platform for the high-energy-level electrons of FO. Moreover, nanosized Ag on SO functions as a cocatalyst to further improve the charge separation and facilitate the catalytic reduction. This work provides a feasible design strategy for narrow-bandgap semiconductor-based photocatalysts by combining an electron platform and a cocatalyst. Full article
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15 pages, 12175 KiB  
Article
Design and Architecture of P-O Co-Doped Porous g-C3N4 by Supramolecular Self-Assembly for Enhanced Hydrogen Evolution
by Ximiao Zhu, Fan Yang, Jinhua Liu, Guangying Zhou, Dongdong Chen, Zhang Liu and Jianzhang Fang
Catalysts 2022, 12(12), 1583; https://doi.org/10.3390/catal12121583 - 5 Dec 2022
Cited by 2 | Viewed by 1390
Abstract
A novel phosphorus and oxygen co-doped graphitic carbon nitride (sheetP-O-CNSSA) photocatalyst was successfully synthesized and applied for H2 evolution under visible light. In the synthesis process of sheetP-O-CNSSA, the supramolecular complex was developed by the [...] Read more.
A novel phosphorus and oxygen co-doped graphitic carbon nitride (sheetP-O-CNSSA) photocatalyst was successfully synthesized and applied for H2 evolution under visible light. In the synthesis process of sheetP-O-CNSSA, the supramolecular complex was developed by the self-assembly and copolymerization reaction among melamine, cyanuric acid (CA) and trithiocyanuric acid (TCA) to act as g-C3N4 precursors, while (NH4)2HPO4 was applied as P and O precursors for element doping. The chemical structures, morphologies, and optical properties of the sheetP-O-CNSSA were characterized by a series of measurements, i.e., XRD, FT-IR, SEM, TEM, UV-vis DRS, and PL. The results suggested that the introduction of P and O elements could enhance the separation and migration efficiency of photogenerated electrons and holes in the energy band of g-C3N4. The photocatalytic tests over Erythrosin B (EB) sensitized sheetP-O-CNSSA indicated that the hydrogen evolution was greatly enhanced compared with other catalysts and non-sensitized sheetP-O-CNSSA under visible light irradiation. Finally, a possible dye-sensitized photocatalysis mechanism was also proposed on the basis of the as-obtained results. Full article
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