Enhanced photocatalytic hydrogen evolution over Ce–TiO2/graphite/g-C3N4 ternary S-scheme heterojunction

Abstract

Efficient charge separation is of great significance for achieving high-efficient photocatalytic H2 evolution (PHE) performance. However, charge separation remains a big challenge owing to serious charge recombination in a single photocatalyst material. In this study, we engineered a composited material composed of one-dimensional (1D) cerium (Ce)-doped TiO2/graphite/g-C3N4 (TC/GR/CN) S-scheme ternary heterojunction by using an in-situ tri-coaxial electrospinning method for efficient solar-driven H2 generation. Experimental and theoretical investigations confirmed that the polarization effect of the conductive graphite could strengthen the internal electric field (IEF) to improve the interfacial charge transfer between Ce-doped TiO2 to g-C3N4. The close-contact heterointerfaces and S-scheme charge transfer pathway in the Ce-doped TiO2/graphite/g-C3N4 hybrid could accelerate the separation of photoexcited charge carriers and optimize H* adsorption/desorption properties. Consequently, the Ce-doped TiO2/graphite/g-C3N4 exhibited a superior photocatalytic H2 generation rate of 3.05 mmol·g−1·h−1, which was 38.7 folds higher than those of conventional single g-C3N4 catalyst. This work proposes a facile and controllable electrospinning strategy for designing ideal hydrogen evolution photocatalysts, which may stimulate further studies on developing the advanced catalyst systems.