Multiple roles of 2D conductive metal-organic framework enable noble metal-free photocatalytic hydrogen evolution

Developing advanced catalysts with high electron-hole separation efficiency and sufficient active centers for redox reaction is vital for photocatalytic hydrogen evolution. Herein, a synergetic system constructed by 2D conductive Ni3(HITP)2 MOF and TiO2 was elaborated to address this challenge for the first time. Photoelectrochemical experiments verify that Ni3(HITP)2 can greatly facilitate the charge separation and charge transfer efficiency of the catalytic heterostructure of Ni3(HITP)2/TiO2. Meanwhile, photocatalytic hydrogen evolution reaction, UPS tests and EPR measurement indicate that Ni3(HITP)2 can serve as co-catalyst which can provide reactive sites for hydrogen reduction. Benefiting from the multiple roles of Ni3(HITP)2, the photosensitive inorganic semiconductor and conductive MOF synergistically realize noble-metal free photocatalysis, rendering>7 times improved hydrogen evolution performance than pristine TiO2. This work gives insight into the mechanism of electroconductive MOF as cocatalyst for hydrogen evolution, which will further inspire the design of advanced electroconductive MOF applied for photocatalysis.