Promoting solar-to-hydrogen evolution on Schottky interface with mesoporous TiO₂-Cu hybrid nanostructures

Developing a highly efficient photocatalysis system based on a photocatalyst-cocatalyst host for the hydrogen evolution reaction has potential but is still challenging. Herein, we report enhanced splitting of water achieved by loading copper metal particles on mesoporous TiO₂ microrods through involving of dual ligand agents into the reaction system. The composition, structure, and surface characteristics of the TiO₂-Cu hybrid were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy, and nitrogen adsorption. The formation of a Schottky contact in the interface between the Cu metal and the n-type semiconductor TiO₂ was confirmed experimentally by photo/electrochemical measurements. This Schottky junction, the TiO₂-Cu hybrid photocatalyst, exhibited superior hydrogen evolution capability with rate of 6046 μmol g^-1 h^-1, which is 23 times higher than that of pristine TiO₂ (260 μmol g^-1 h^-1). The experimental results demonstrated that efficient separation and transfer of photo-induced electron-hole pairs greatly contributed to the enhanced photocatalytic H₂ evolution. The Schottky contact between Cu and TiO₂ as well as cocatalyst characteristic of Cu play significant roles in preventing the recombination of electron-hole pairs and enhancing water splitting to form hydrogen. This study demonstrates a rational design to construct Schottky contacts in metal-semiconductor junctions to significantly boost their photocatalytic capacity.