Photocatalytic water-splitting for hydrogen production using TiO 2 -based catalysts: Advances, current challenges, and future perspectives

Hydrogen has been recognized as a viable energy carrier due to zero emissions, emphasizing its superior energy capacity and ecological sustainability. Various technologies can produce hydrogen, but not all are environmentally acceptable. Photocatalytic water splitting by sunlight has gained much attention as a favorable alternative for generating renewable energy and combating climate change in recent years. Extensive research into this method has been prompted because of its tremendous capability for effective and economical hydrogen production. In recent years, the utilization of common semiconductor-based photocatalysts for generating hydrogen via water splitting has been investigated. TiO2 photocatalysts have shown great promise for hydrogen production because of their unique physicochemical features. In this review, we also use photocatalysts based on TiO2 to produce H2 through photocatalytic water splitting. Nevertheless, the large band gap, slow electron-hole recombination rate, and excessive potential for H2 production still need to be addressed. Numerous methods, including doping, semiconductor coupling, defect engineering, and dye sensitization, have been focused on boosting the photocatalytic activity of TiO2 and thus mitigating these drawbacks. This review provides a critical overview of recent research on the various variables influencing the photocatalytic process in dynamic H2 production. These factors include the photocatalysts' surface area and particle size, TiO2 loading, pH, temperature, light source and intensity, sacrificial reagents, and band gap energy. As a result, the TiO2-based photocatalyst is more predictable and shows potential for future research and development for the production of H2.