Novel solar light driven photocatalyst, zinc indium vanadate for photodegradation of aqueous phenol

Advanced Oxidation technologies (AOTs) are gaining attention as an effective waste water treatment methodology capable of degrading diverse spectrum of recalcitrant organic contaminants and microbes. Undoubtedly, photocatalysis is a promising AOT to alleviate the problem of water pollution. Despite recent research into other photocatalysts (e.g. ZnO, ZnS, Semiconductor-Graphene composites, perovskites, MoS 2, WO 3 and Fe 2 O 3), titanium dioxide (TiO 2) remains the most popular photocatalyst due to its low cost, nontoxicity and high oxidising ability. Moreover, titania photocatalysts can easily be immobilized on various surfaces and be scaled up for large scale water treatment. The current review aims to highlight recent advancements in photocatalytic AOTs with main emphasis on TiO 2 photocatalysis. This review also discusses the use of TiO 2 photocatalysis for water and waste treatment, treating contaminants of emerging concern (CECs), pesticides, endocrine disrupters (EDs) and bacteria using both UV and visible light irradiations. It was concluded that with efficient photoreactor configuration and further studies on the photocatalyst regeneration, TiO 2 photocatalysis is a viable option for the reclamation of agricultural/irrigational waste water. Novel doped photocatalysts such as ZnS-CuS-CdS, carbon spheres/CdS, g-C 3 N 4-Au-CdS, ZnS-WS 2-CdS, C 3 N 4-CdS and Pd-Cr 2 O 3-CdS have also been discussed. Finally, the advances in the actively studied metal organic framework based photocatalysts that are emerging as effective alternate for metal oxide based photocatalysts is also discussed in detail.

Catalysts, 2023

Semiconductor-based photocatalytic reactions are a practical class of advanced oxidation processes (AOPs) to address energy scarcity and environmental pollution. By utilizing solar energy as a clean, abundant, and renewable source, this process offers numerous advantages, including high efficiency, eco-friendliness, and low cost. In this review, we present several methods to construct various photocatalyst systems with excellent visible light absorption and efficient charge carrier separation ability through the optimization of materials design and reaction conditions. Then it introduces the fundamentals of photocatalysis in both clean energy generation and environmental remediation. In the other parts, we introduce various approaches to enhance photocatalytic activity by applying different strategies, including semiconductor structure modification (e.g., morphology regulation, co-catalysts decoration, doping, defect engineering, surface sensitization, heterojunction construction) and tuning and optimizing reaction conditions (such as photocatalyst concentration, initial contaminant concentration, pH, reaction temperature, light intensity, charge-carrier scavengers). Then, a comparative study on the photocatalytic performance of the various recently examined photocatalysts applied in both clean energy production and environmental remediation will be discussed. To realize these goals, different photocatalytic reactions including H 2 production via water splitting, CO 2 reduction to value-added products, dye, and drug photodegradation to lessen toxic chemicals, will be presented. Subsequently, we report dual-functional photocatalysis systems for simultaneous energy production and pollutant photodegradation for efficient reactions. Then, a brief discussion about the industrial and economical applications of photocatalysts is described. The report follows by introducing the application of artificial intelligence and machine learning in the design and selection of an innovative photocatalyst in energy and environmental issues. Finally, a summary and future research directions toward developing photocatalytic systems with significantly improved efficiency and stability will be provided.

International Journal of Photoenergy, 2013

The development of nanotechnology for the synthesis of nanomaterials is providing unprecedented opportunities to deal with emerging environmental problems associated with water and air contamination along with worldwide energyrelated concerns. Advanced oxidation technologies (AOTs) and nanotechnologies (AONs) have been extensively investigated for the destruction of toxic and recalcitrant organic compounds and inactivation of microorganisms in water and air. Photocatalysis as a part of AOTs is an effective method to completely decompose organic pollutants in air and aqueous solutions/natural waters. However, conventional wide band gap semiconducting materials (TiO 2 , ZnO, etc.) usually employed in photocatalytic processes absorb radiation below 400 nm, which is in the UV region, being only 5% of the solar light. In order to effectively utilize solar light as the source of energy, modified materials that can also absorb in the visible spectrum need to be synthesized. Recently, doping TiO 2 with different heteroatoms (metal and/or nonmetal ions) made it possible to shift the absorption towards longer wavelengths and, thus, allow TiO 2 sensitization in the visible region. Due to the visible light absorption abilities, doped TiO 2-based powders and films can also be used for improving the photocatalytic process in the visible region. Several attempts have been directed towards the development of modified TiO 2 with visible light response by dye sensitization, metal (Fe, Co, Ag), and nonmetal (N, F, C, S) doping of the catalyst to reduce TiO 2 band gab energy

International Journal of Hydrogen Energy, 1990

A~traet--Different semiconductor photocatalytic systems to produce H 2 by visible light have been tested: (I) Pt/TiO 2 plus sensitizers like Ru(bipy)3 z+ and RuL 2+ (L = 2,2'-bipyridine-4,4'-dicarboxylate), (2) naked CdS, Pt/CdS and RuO2/CdS, and (3) mixtures of CdS + Pt/TiO2, and CdS and ZnS coprecipitated on ?-AI203 . EDTA, isopropanol, sulfide and sulfide/sulfite mixtures were used as sacrificial agents. The photocatalytic systems which used sensitizers showed a poor stability and they only produced H 2 when EDTA was used as sacrificial agent. The mixture CdS + Pt/TiO2 gave the highest reaction rates for H2 production in isopropanol medium, and CdS, naked or with Pt deposits, produced the best results when sulfide or sulfide/sulfite as sacrificial agents were used. The addition of sulfite to a sulfide aqueous solution increased the H2 production rate about four times with respect to the case when only sulfide was employed. The maximum photochemical and energy efficiencies obtained were 13.2 and 5.0%, respectively, with reference to the wavelength range 300-520 nm.

Various strategies have been designed to efficiently utilize the solar radiation and to enhance the efficiency of photocatalytic processes. Building on the fundamental strategies to improve the visible light activity of TiO2-based photocatalysts, this Perspective aims to give an insight into many contemporary developments in the field of visible-light-active photocatalysis. Various examples of advanced TiO2 composites have been discussed in relation to their visible light induced photoconversion efficiency, dynamics of electron− hole separation, and decomposition of organic and inorganic pollutants, which suggest the critical need for further development of these types of materials for energy conversion and environmental remediation purposes.

Concepts of Semiconductor Photocatalysis, 2019

Semiconductor photocatalysis gained reputation in the early 1970s when Fujishima and Honda revealed the potential of TiO 2 to split water in to hydrogen and oxygen in a photoelectrochemical cell. Their work provided the base for the development of semiconductor photocatalysis for the environmental remediation and energy applications. Photoactivity of some semiconductors was found to be low due to larger band gap energy and higher electron-hole pair recombination rate. To avoid these problems, the development of visible light responsive photocatalytic materials by different approaches, such as metal and/or non-metal doping, codoping, coupling of semiconductors, composites and heterojunctions materials synthesis has been widely investigated and explored in systematic manner. This chapter emphasizes on the different type of tailored photocatalyst materials having the enhanced visible light absorption properties, lower band gap energy and recombination rate of electron-hole pairs and production of reactive radical species. Visible light active semiconductors for the environmental remediation purposes, particularly for water treatment and disinfection are also discussed in detail. Studies on the photocatalytic degradation of emerging organic compounds like cyanotoxins, VOCs, phenols, pharmaceuticals, etc., by employing variety of modified semiconductors, are summarized, and a mechanistic aspects of the photocatalysis has been discussed.

2016

• Principles of semiconductors and photocatalysts were investigated due to their applications in the advanced oxidation processes. • Various improvement strategies in photocatalysts were discussed. • Recent developments in photocatalytic reactors in wastewater treatment were investigated.

Materials Science and Engineering: B, 2018

CdS nanoparticles (NPs), ZnO layers, and CdS/ZnO composite were successfully prepared by a two-step chemical method. From the analysis of XRD, cubic CdS and the hexagonal ZnO phase were described for the synthesized samples. The CdS/ZnO composite exhibited larger surface area (99.9 m 2 g -1 ) than pure CdS NPs (50.5 m 2 g -1 ) and ZnO layers (67.3 m 2 g -1 ), respectively. The band gap energies evaluated from the DRS results were 3.40, 2.13 and 1.78 eV for pure ZnO, CdS and CdS/ZnO composite respectively. The photocatalytic activity of the prepared materials was studied by the degradation of dye in aqueous solution under UV-Visible light exposure. CdS/ZnO composite exhibited the superior photocatalytic activity than ZnO and CdS. The photocatalytic performance was achieved 91.5% degradation in composite sample.

Clean Technologies and Environmental Policy, 2019

Pharmaceuticals are one of the persistent emerging contaminants that are ubiquitous in the aquatic environment due to their extensive application as human and veterinary medicines. The ecotoxicity and microbial resistance are considered to be major adverse environmental and health impact of pharmaceuticals even in trace amounts, which raise global concern. The recalcitrant nature of these pollutants restricts the application of the conventional treatment system for their remediation and triggers extensive research on the various advanced oxidation processes as a promising treatment system. Among them, visible-light-assisted semiconductor photocatalysis has significant potential as an efficient, low-cost, and green technology, which can use even solar energy as a clean and sustainable light source. A comprehensive review on the application of various visible light photocatalysts on the degradation of aqueous pharmaceutical pollutants was attempted to highlight their physiochemical properties, reaction mechanism, and catalytic activity in the laboratory-as well as field-scale operations. The challenges and gaps in the current literature have been identified, and recommendations for prospective research opportunities have been placed based on the findings.

Energy Materials, 2022

The development of green and renewable energy is becoming increasingly more important in reducing environmental pollution and controlling CO 2 discharge. Photocatalysis can be utilized to directly convert solar energy into chemical energy to achieve both the conversion and storage of solar energy. On this basis, photocatalysis is considered to be a prospective technology to resolve the current issues of energy supply and environmental pollution. Recently, several significant achievements in semiconductor-based photocatalytic renewable energy production have been reported. This review presents the recent advances in photocatalytic renewable energy production over the last three years by summarizing the typical and significant semiconductorbased and semiconductor-like photocatalysts for H 2 production, CO 2 conversion and H 2 O 2 production. These reactions demonstrate how the basic principles of photocatalysis can be exploited for renewable energy production. Finally, we conclude our review of photocatalytic renewable energy production and provide an outlook for future related research.