Recent progress on the solid-state materials for photocatalysis

In the current timeline, hydrogen is considered one of the greatest clean and green fuels. It is regarded as an alternative energy source to fossil fuels, which has the potential to meet the current energy supply. However, due to the limitations of technology, the production of hydrogen has not been commercialized even though we have plenty of naturally stored hydrogen in the compound form. Numerous studies have been performed from the beginning, and various methods have been developed to obtain hydrogen from its compound, such as electrolysis, thermolysis, biophotolysis, and photocatalysis. Among these methods, photocatalysis is considered one of the best ways to produce hydrogen because of carbon-free and uses renewable sources of energy. Being benign to the environment this method is facing limitations due to lack of optimal photocatalyst having suitable band energy with proper band edge alignment required for hydrogen evolution reaction. Even though noble metals show excellent photocatalytic reactions, because of their low availability and high cost limit their practical applications. In this review, the drawbacks of various hydrogen production methods are highlighted. Among the numerous applications reductions of carbon dioxide, dye degradation, and photocatalytic hydrogen evolution reactions have been discussed here. Photocatalysts such as metal oxides, perovskites, graphitic carbon nitride, etc. were discussed based on their ability to produce hydrogen and the different methods employed for their enhancement.