Design strategy for photocatalytic hydrogen evolution reaction of TiO2: A review

In several applications of artificial photosynthesis, photocatalytic hydrogen evolution reaction can realize the conversion of light energy to hydrogen energy, showing great potential in achieving sustainable energy utilization. TiO2 is the first photocatalyst used for photocatalytic hydrogen evolution. It has attracted much attention due to its stability and low cost. However, the original TiO2 faces the problems of difficult charge excitation, low carrier utilization rate, and limited photocatalytic hydrogen production efficiency, which makes it challenging to achieve industrial demand. This review summarizes strategies for the evolution of TiO2 into natural photosystem based on thermodynamics and kinetics, including defect engineering, junction engineering, and cocatalyst engineering. Subsequently, other promising optimization strategies for photocatalytic systems were also reviewed. Finally, various problems in the industrialization of TiO2 for photocatalytic hydrogen production were proposed. It was found that the evolution of TiO2 into a natural photosystem is an effective solution to improve its hydrogen evolution activity. Moreover, superior to the photosystem, its catalytic efficiency is allowed to be further improved by other optimization strategies such as introducing thermal effects. To design excellent TiO2 for hydrogen evolution reaction, it is necessary to handle the development trend of these evolution strategies.