Plasmon Au/K-doped defective graphitic carbon nitride for enhanced hydrogen production

Abstract

Knowledge of the photocatalytic H₂-evolution mechanism is of critical importance for water splitting, and for designing active catalysts for a sustainable energy supply. In this study, we prepared plasmon Au-modified K-doped defective graphitic carbon nitride (Au/KCNx) and then applied it in photocatalytic hydrogen-production tests. The hydrogen-production rate of the Au/KCNx photocatalyst (8.85 mmol g⁻¹ h⁻¹) was found to be almost 104 times higher than that of Au/g-C₃N₄ (0.085 mmol g⁻¹ h⁻¹), together with an apparent quantum efficiency of 12.8% at 420 nm. It could significantly improve the photocatalytic activities of the Au/KCNx sample, which was attributed to the synergistic effects of the plasmon effect, potassium doping, and nitrogen vacancy. In addition, the Au/KCNx photocatalyst had a large surface area, which was beneficial for photogenerated carrier separation and transfer. The novel strategy proposed here is a potential new method for the development of graphitic carbon nitride photocatalysts with obviously enhanced activities.