Efficient spatial charge separation and transfer in ultrathin g-C3N4 nanosheets modified with Cu2MoS4 as a noble metal-free co-catalyst for superior visible light-driven photocatalytic water splitting

Developing photocatalysts with efficient spatial charge separation and transfer as well as a high ligh-tharvesting ability remains a key challenge. Here, we report a facile in situ process to decorate ultrathin g-C3N4 nanosheets (NSs) with a co-catalyst, Cu2MoS4, for photocatalytic water splitting. The as-obtained Cu2MoS4/g-C3N4 exhibits a superior photocatalytic H-2 evolution rate of 2170.5 mu mol h(-1) g(-1) under visible light irradiation, which is nearly 677 and 34 times higher than that of bulk g-C3N4 and g-C3N4 NSs, respectively, and far exceeds that of most g-C3N4 catalysts modified with other sulphide co-catalysts reported in the literature, demonstrating that Cu2MoS4 can serve as a promising non-noble metal co-catalyst to couple with g-C3N4 for highly efficient photocatalysts. Structural characterization confirms the well-defined morphology of Cu2MoS4/g-C3N4 in which Cu2MoS4 hollow spheres are uniformly attached on the ultrathin g-C3N4 NSs with numerous micropores and vacancies. The optical properties indicate that Cu2MoS4/gC(3)N(4) possesses a superb visible light absorption ability. The photoluminescence spectra, photocurrent response, and electrochemical impedance spectra combine to prove the highly efficient separation and migration of photogenerated electrons and holes. All these factors synergistically enhance the photocatalytic activity of Cu2MoS4/g-C3N4 for photocatalytic water splitting, providing new insights into the rational design of high-performance visible light-driven photocatalysts based on earth-abundant elements.