Engineering a Self‐Grown TiO2/Ti‐MOF Heterojunction with Selectively Anchored High‐Density Pt Single‐Atomic Cocatalysts for Efficient Visible‐Light‐Driven Hydrogen Evolution

A photocatalyst TiO2/Ti‐BPDC‐Pt is developed with a self‐grown TiO2/Ti‐metal–organic framework (MOF) heterojunction, i.e., TiO2/Ti‐BPDC, and selectively anchored high‐density Pt single‐atomic cocatalysts on Ti‐BPDC for photocatalytic hydrogen evolution. This intimate heterojunction, growing from the surface pyrolytic reconstruction of Ti‐BPDC, works in a direct Z‐scheme, efficiently separating electrons and holes. Pt is selectively anchored on Ti‐BPDC by ligands and is found in the form of single atoms with loading up to 1.8 wt %. The selective location of Pt is the electron‐enriched domain of the heterojunction, which further enhances the utilization of the separated electrons. This tailored TiO2/Ti‐BPDC‐Pt shows a significantly enhanced activity of 12.4 mmol g−1 h−1 compared to other TiO2‐ or MOF‐based catalysts. The structure‐activity relationship further proves the balance of two simultaneously exposed domains of heterojunctions is critical to fulfilling this kind of catalyst. A Z‐scheme heterojunction TiO2/Ti‐BPDC‐Pt with selectively anchored high‐density Pt single‐atomic cocatalysts is synthesized by leveraging the chelating functionality of ligands and finely controlled surface reconstruction of Ti‐BPDC. The high activity is confirmed due to the efficient charge separation promoted by the heterojunction and the selective location of Pt single‐atomic cocatalysts on the electron‐enriched domain of the heterojunction.