TiO2@Ti MOFs hollow double-shell structure by in-situ self-sacrificial hydrolytic etching for enhanced photocatalytic hydrogen evolution

Due to their high porosity and structural tunability, MOFs are widely used in photocatalytic hydrogen production. However, unmodified MOFs often suffer from rapid recombination of photogenerated electron-hole pairs. It is a good strategy to construct heterostructures by coupling them with other semiconductor materials. In this paper, hollow double-shell heterostructures TiO2@NM/Ni10% were prepared in situ using tannic acid as a protecting agent. The hydrogen production efficiency of the sample etched for 20 min was as high as 1659.9 mu mol h(- 1) g(- 1), which was attributed to the formation of Ti4+/Ti3+ double-cycled electron transfer channels between NM/Ni10% and TiO(2 )and the strong built-in electric field established by the type-II heterojunction accelerated the photogenerated carrier separation and transport, which greatly improved the photocatalytic hydrogen production efficiency. In addition, the domain-limiting effect of the hollow double-shell structure enables water molecules to form strong interactions with TiO2, providing abundant reaction sites for the catalytic reaction. This structure extends the optical path and enhances light absorption. In this study, a strategy to promote photogenerated carrier separation in MOFs materials by constructing heterojunctions through in situ hydrolysis is proposed, which provides insights for the preparation of efficient hydrogen-producing MOFs photocatalysts.