Boosting photocatalytic hydrogen evolution using a noble-metal-free co-catalyst: CuNi@C with oxygen-containing functional groups

Oxygen functional groups are often overlooked in most carbon coated co-catalyst for photocatalytic hydrogen evolution, and its influences on proton reduction are not been well considered. In this work, a noble-metal-free co-catalyst CuNi alloy nanoparticle wrapped in a carbon layer containing oxygen-containing functional groups ([email protected]O) was designed and synthesized. Under visible light irradiation, the photocatalytic H2 evolution rate of [email protected]O/g-C3N4 was 2.36 mmol g−1 h−1, which was higher than that of Pt co-catalyst at the same conditions. Density functional theory calculations and mechanistic studies indicate that the H adsorption free energy on the [email protected]O was more suitable for hydrogen evolution than that of Pt, where the CO groups on the carbon layer surface modulated the work function of CuNi alloy. It is believed that the understanding the function of surface CO group can broaden the research directions of photocatalyst modification and improve the activity of photocatalytic hydrogen evolution.