Semiconductor-Cocatalyst Interfacial Electron Transfer Dominates Photocatalytic Reaction

In photocatalytic systems, the transfer of electrons from semiconductor nanostructures to the reduction cocatalysts is the key electronic process, which determines the effective separation of photogenerated charge carriers, and is sensitively influenced by the band structures of the contacts. Due to improper adoption of cocatalysts, interfacial charge transfer is usually suffering from excessive energy dissipation by thermionic emission, which kinetically prevents this electronic process and eventually aggravates the recombination of photogenerated charge carriers. Unfortunately, this issue has hardly been consciously considered. The formed potential barriers, which are mainly determined by the adoption of cocatalyst, kinetically predominates the interfacial charge transfer as well as the whole photocatalytic reaction. In this work, inspired by theoretical simulation, we adopt platinum and MoS2 that deposited on semiconductor nanostructures as the models to demonstrate the energy dissipation that kinetically influences the interfacial charge transfer. Despite high catalytic activity, the intolerably high energy dissipation for interfacial charge transfer hides the superiority of platinum, resulting in an inferior photocatalytic performance to that of MoS2. Our work rationally unfastens the deliberative consideration of intrinsic activity and prompts the exploration of cocatalysts for photocatalyst designing.