Anchoring Single Nickel Atoms on Carbon-vacant Carbon Nitride Nanosheets for Efficient Photocatalytic Hydrogen Evolution

Polymeric carbon nitride(PCN) has emerged as a promising candidate for photocatalytic hydrogen evolution, but its dependence on scarce and high-cost noble metal co-catalysts severely limits its extensive application. It will be of great promise to develop non-noble metal single-atom co-catalysts with low-cost and high atom utilization to improve the photocatalytic performance over PCN. Herein, single Ni atoms are successfully anchored onto carbon-vacant PCN nanosheets(CCN-SANi) via a two-step ammonia thermal treatment and photo-deposition process. Theoretical calculations and experimental results demonstrate that the optical absorption property and the charge transfer ability of CCN-SANi have been significantly improved with the introduction of single Ni atoms to form Ni-N₃ sites. In comparison to carbon-vacant PCN(CCN) loaded with Ni clusters, the obtained CCN-SANi exhibits 11.4 times increased photocatalytic performance, with the highest hydrogen evolution rate reaching 511 μmol/(g·h), which is even 1.7 times higher than that of CCN loaded with Pt clusters. This research proposes an inspiring and reliable strategy to design novel single-atom semiconducting polymers with electronic structures manipulated for efficient photocatalysis.