Supercritical CO2 produces the visible-light-responsive TiO2/COF heterojunction with enhanced electron-hole separation for high-performance hydrogen evolution

Abstract

To construct the heterojunctions of TiO2 with other compounds is of great importance for overcoming its inherent shortages and improving the visible-light photocatalytic performance. Here we propose the construction of TiO2/covalent organic framework (COF) heterojunction with tight connection by a supercritical CO2 (SC CO2) method, which helps bridging the transformation paths for photo-induced charge between TiO2 and COF. The produced TiO2/COF heterojunction performs a H2 evolution of 3,962 µmol·g−1·h−1 under visible-light irradiation, which is ∼ 25 times higher than that of pure TiO2 and 4.5 folds higher than that of TiO2/COF synthesized by the conventional solvothermal method. This study opens up new possibilities for constructing heterojunctions for solar energy utilization.