A defective g-C3N4/RGO/TiO2 composite from hydrogen treatment for enhanced visible-light photocatalytic H2 production

Abstract

Photocatalytic H₂ evolution is a clean technology to alleviate energy and environmental issues. The limited light absorption and the separation efficiency of photogenerated charge carriers are the major hurdles constraining the application of numerous photocatalysts. Herein, we report a simple and effective strategy, a multistep heat-treatment method, to synthesise a defective g-C₃N₄/RGO/TiO₂ composite to increase its rate of activity for H₂ production. The defects, nitrogen and oxygen vacancies, are simultaneously introduced on the surface of the g-C₃N₄/RGO/TiO₂ composite. The vacancy defects essentially endow g-C₃N₄/RGO/TiO₂ with a boosted photocatalytic H₂ evolution rate (4760 μmol h⁻¹ g⁻¹) under visible-light irradiation, which is higher than that of the most of g-C₃N₄/TiO₂ composites. This is attributed to the improved visible-light absorption as well as the separation and transfer rate of photogenerated charge carriers arising from vacancy defects. This study may provide an avenue for preparing defective photocatalysts for efficient H₂ evolution.