Three-dimensional ordered macroporous g-C3N4-Cu2O-TiO2 heterojunction for enhanced hydrogen production

Abstract

In this study, a g-C3N4-Cu2O-TiO2 photocatalyst with a novel three-dimensional ordered macroporous (3DOM) structure was successfully prepared using a sacrificial template strategy and a photodeposition method. The influence of the special porous structure with cross pore channels on the photocatalytic properties of the as-prepared sample was studied in detail. Compared with the original photocatalyst (TiO2 with 3 wt% Pt), g-C3N4-Cu2O-TiO2 exhibited a higher specific surface area and more active sites, thus accelerating the separation efficiency of the photogenerated electron-hole pair. Consequently, the as-prepared photocatalyst showed good photocatalytic performance, reaching a maximum hydrogen production rate of 12,108 µmol g−1 h−1 and approximately five times higher than that of the pristine comparison sample. The enhanced photoactivity of the g-C3N4-Cu2O-TiO2 heterojunction can be ascribed to its double p-n heterojunction and robust porous structure, where the photodeposited Cu2O plays a synergistic catalytic role in the photocatalytic process and the outer clad g-C3N4 layer prevents Cu2O oxidation. Additionally, the possible photocatalytic mechanism was briefly discussed based on the experimental results. This work identifies viable pathways for developing low-cost heterojunction photocatalysts with highly efficient photocatalytic activity toward improved solar energy conversion.