Recent Strategies to Improve the Photocatalytic Efficiency of TiO2 for Enhanced Water Splitting to Produce Hydrogen

Hydrogen production is one of the best solutions to the growing energy concerns, owing to its clean and sustainable assets. The current review gives an overview of various hydrogen production technologies, highlighting solar water splitting as a promising approach for its sustainable production. Moreover, it gives a detailed mechanism of the water-splitting reaction and describes the significance of titania-based catalysts for solar water splitting. It further highlights diversified strategies to improve the catalytic efficiency of TiO2 for the enhanced hydrogen production. These strategies include the doping of TiO2, dye sensitization, and the addition of co-catalysts. Doping reduces the bandgap by generating new energy levels in TiO2 and encourages visible-light absorption. Sensitization with dyes tunes the electronic states, which in turn broadens the light-absorption capacity of titania. Constructing heterojunctions reduces the charge recombination of TiO2, while co-catalysts increase the number of active sites for an enhanced reaction rate. Thus, every modification strategy has a positive impact on the stability and photocatalytic efficiency of TiO2 for improved water splitting. Lastly, this review provides a comprehensive description and future outlook for developing efficient catalysts to enhance the hydrogen production rate, thereby fulfilling the energy needs of the industrial sector.