Recent advances in utilization of wide band gap metal oxides for photocatalysis of organic waste

Abstract

Water cleaning has become a major challenge in the current scenario with huge amounts of industrial wastes being accumulated in the water bodies over the years. Traditional chemical, physical and biological processes for treating wastewater containing textile dye have disadvantages such as high cost, high energy requirement and generates secondary pollution during treatment process. The progressive oxidation processes technology has been appealing growing attention for the decomposition of organic dyes. Such processes are based on the light-enhanced generation of highly reactive hydroxyl radicals, which oxidize the organic matter in solution and convert it completely into water, CO2 and inorganic compounds. Photocatalytic degradation using semiconductor materials has emerged as a promising technique by utilizing abundant solar light. We present a theoretical investigation on effect of catalyst properties on the photo catalytic activity of metal oxide nanomaterials. The focus of this review lies on the use of different nanostructures of tin oxide material for enhanced rate of photo-catalysis. First, a brief overview of photocatalytic degradation mechanism is presented followed by various techniques of nanomaterial synthesis. Various factors (concentration, light intensity, pH, temperature, doping concentration, and time of irradiation of sunlight) that affect the efficiency of photocatalytic degradation process have been discussed in detail. In this review, an attempt to explain the basic mechanism of photocatalytic water splitting and fundamental material requirements for particular photocatalysts. The paper concludes with discussions on current material issues, challenges and outlook for future photocatalyst development.