Multifunctional Conductive MOFs Enhance the Photocatalytic Hydrogen Evolution Efficiency of S-Type Ni3(HITP)2/TiO2 Heterojunctions

Despite their high surface area, remarkable porosity, and efficient charge transfer mechanisms, conductive MOFs have found limited utilization within the domain of photocatalysis. In this study, we synthesized a cutting-edge S-type Ni₃(HITP)₂/TiO₂ heterojunction photocatalyst exhibiting outstanding light harvesting and prolonged lifetime of photogenerated electrons through an in situ synthesis approach. Compared with TiO₂, the composite materials not only significantly increase the specific surface area by 4.07 times but also expand the visible light absorption edge from 400 to 1100 nm. The hydrogen production rate of Ti/Ni-3 reached 4.927 mmol·g^–1·h^–1, which is 4.51 times that of TiO₂. The S-type interface charge transfer pathway of the Ni₃(HITP)₂/TiO₂ composite material was inferred by band structure, in situ XPS, SPV, and free radical capture, which improves charge separation and extends the carrier lifetime to undergo directional migration driven by an IEF. This is the main reason for the improved photocatalytic performance of Ni₃(HITP)₂/TiO₂ composite materials.