Mesoporous TiO2 mixed crystals for photocatalytic pure water splitting

Semiconductor mesoporous single crystals have attracted considerable attention due to the merits of excellent light absorption ability and large surface area for photocatalysis capability. However, most of the materials have a relative large size (~um), which can hardly suppress the recombination of photogenerated electrons and holes. In this work, we synthesized a series of nano mesoporous TiO2 mixed crystals (brookite and rutile) with high carrier transfer efficiency, improved mass transfer and diffusion abilities, which are crucial for the outstanding photocatalytic performance. Meanwhile, the key factors in the growth process and mechanism of the mesoporous TiO2 mixed crystals were addressed. With the assistance of Pt nanoparticles, H2 and H2O2 production can be simultaneously achieved and the efficiencies can reach up to 9.46 ± 0.56 and 3.29 ± 1.28 μmol mg−1 h−1, respectively. The H2 evolution rate is 2.8-fold higher than that of the reported TiO2 nanoparticle catalyst (3.34 μmol mg−1 h−1). The excellent photocatalytic efficiency can be attributed to the special mixed crystal structure of the mesoporous TiO2 crystals. This work provides new ideas and guidance for precise synthesis of nano mesoporous TiO2 mixed crystals and enhancing their water splitting performance with high value-added products.