Electronic tuning of g-C3N4 via competitive coordination to stimulate high-efficiently photocatalytic for hydrogen evolution

Abstract Photocatalytic water splitting under irradiation by sunlight to achieve hydrogen with the participation of semiconductor materials is deemed as the most promising green and clean energy supply strategy. Hence, it is particularly important and emergency to design photocatalyst with both high activity and stability to perform high-efficiency hydrogen evolution reaction (HER). In this study, we report a competitive coordination strategy to modulate the electron and band structure of g-C3N4 dramatically improving the HER kinetics. Experimental and density functional theory (DFT) calculations results inferred that the modified g-C3N4 by copolymerizing urea and diaminodiphenyl sulfone can promote the effective separation of photogenerated electrons and holes, and simultaneously significantly increase the fluorescence lifetime of g-C3N4. Specifically, the hydrogen generation rate is 3.7 or 9.6 folds higher of the original carbon nitride at λ > 400 nm and λ > 420 nm, respectively. Additionally, the optimal catalyst exhibits a high apparent quantum yield (7.02%) when the incident wavelength is 420 nm as well as excellent stability. This work will shed a spick-and-span insight for conception and preparation of high-powered metal-free photocatalysts.