Photocatalytic hydrogen generation using TiO2: a state-of-the-art review

This review is focusing on photocatalytic hydrogen (H-2) production as a viable fuel. The limitations of different production methods for H-2 generation and the importance of photocatalytic process are discussed, which renders this process as highly promising to meet the future energy crises. TiO2 is one of most effective material to generate the H-2 via photocatalytic processes. Therefore, advantages of the catalyst over other semiconductors have been thoroughly analyzed. Starting from synthesis of TiO2 and factors affecting the whole process of photocatalytic H-2 production have been discussed. Modifications for improvement in TiO2 and the photocatalytic reaction are critically reviewed as well as the mechanism of TiO2 modification has been described. Metal doping, non-metal doping, impurity addition and defect introduction processes have been analyzed and the comparison of experimental results is developed based on H-2 production efficiency. A critical review of the literature from 2004 to 2021 concludes that H-2 production as fuel using TiO2 photocatalytic method is efficient and environment friendly, which have potential for practical applications for H-2 generation.