Nano-Sized Photocatalytic Materials for Solar Energy Conversion and Storage

World is presently facing two major problems: Energy crisis and ever increasing environmental pollution as the fossil fuels used today are polluting the environment and these resources are limited only for a few coming decades. nanosized materials are being used these days to provide alternative energy sources to fossil fuels, which is environmentally clean also. The development of newer photocatalytic nanomaterials will enable us to produce and store solar energy in the form of hydrogen. Hydrogen has been advocated as the fuel of future and it can be produced by photo-splitting of water in presence of photocatalytic materials. nanosized photocatalytic materials have also been utilized in solar cells and photocatalytic reduction of carbon dioxide (a step towards artificial photosynthesis). Although, the use of nanosized photocatalytic materials has long miles to go to compete with present day technology (Photovoltaics and use of fossil fules), but there is lot of hopes from this kind of material in years to come. This chapter deals with use of nanomaterials in conversion of solar energy into electricity, photogeneration of hydrogen, and photocatalytic reduction of carbon dioxide. Presently, majority of photovoltaic power comes from bulk semiconductors, and only a limited use has been made of nanosized semiconductors, but there is likely U-turn in coming decades so that nanosemiconductors will have an edge over bulk semiconductors.