Hydrogel microspheres supported TiO2 loaded with Au nanoparticles as a novel photocatalyst for solar-to-hydrogen conversion

Powdered titanium dioxide (TiO 2 ) photocatalysts are widely used in the photodecomposition of water for H 2 production due to their low cost, and high stabilizing activity under UV light . However, it has encountered great challenges in photocatalytic reactions, such as easy aggregation and being difficult to recycle. To solve these problems, we proposed a hydrogel (HY) composite material. The material Au@TiO 2 /HY was created by mixing HY with TiO 2 supported co-catalyst Au nanoparticles (NPs). The results show that Au@TiO 2 /HY is difficult to spread owing to its block shape in the photocatalytic reaction, the H 2 evolution rate is only 4.59 mmol/g/h. Therefore, on account of the fact that hydrogel microspheres (HYM) can enhance performance, Au@TiO 2 /HYM was self-assembled by mechanical methods on the synthesis scheme of Au@TiO 2 /HY, which improves the Ultraviolet and visible (UV–vis) light absorption range. The H 2 evolution rate of Au@TiO 2 /HYM is 17.08 mmol/g/h, which is ∼3.7-fold higher than that of Au@TiO 2 /HY (4.59 mmol/g/h), according to the data. The mechanism studies demonstrate that the HYM improve the UV–vis light absorption range and promote the separation of photogenerated electron-hole pairs in Au@TiO 2 /HYM during photocatalysis compared to typical bulk HY, thus improving the photocatalytic H 2 evolution activity. The results provide a reference for the preparation of recyclable HYM for photocatalytic H 2 production.