ABSTRACT
Photocatalysis is a fantastic way to clean wastewater, industrial efuents, and our environment in general. One can reduce pollution in air and water by modifying and further developing this technology. It can also put a check on the spread of infections and diseases such as severe acute respiratory syndrome (SARS). This cleaner way of life would benet everyone around the globe. A good photocatalyst should be photoactive, able to utilize visible and/or near UV light, biologically and chemically inert, photostable, inexpensive, and nontoxic in nature. The redox potential of the photogenerated valence band (VB) hole must be sufciently positive for a semiconductor to be photochemically active so that it can generate •OH radicals that can subsequently oxidize the organic pollutants. The redox potential of the photogenerated conductance band electron must be sufciently negative to be able to reduce absorbed oxygen to a superoxide. TiO2, ZnO, WO3, CdS, ZnS, SnO2, WSe2, Fe2O3, and so on can be used as effective photocatalysts in combating against the problem of environmental pollution.
