Partial Sulphidation to Regulate Coordination Structure of Single Nickel Atoms on Graphitic Carbon Nitride for Efficient Solar H 2 Evolution.

To develop a non-precious highly efficient cocatalyst to replace Pt on graphitic carbon nitride (g-C 3 N 4 ) for solar H 2 production is great significant, but still remains a huge challenge. The emerging single-atom catalyst presents a promising strategy for developing highly efficient non-precious cocatalyst owing to its unique adjustability of local coordination environment and electronic structure. Herein, this work presents a facile approach to achieve single Ni sites (Ni 1 -N 2 S) with unique local coordination structure featuring one Ni atom coordinated with two nitrogen atoms and one sulfur atom, confirmed by high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, and density functional theory calculation. Thanks to the unique electron structure of Ni 1 -N 2 S sites, the 1095 µmol g -1 h -1 of high H 2 evolution rate with 4.1% of apparent quantum yield at 420 nm are achieved. This work paves a pathway for designing a highly efficient non-precious transition metal cocatalyst for photocatalytic H 2 evolution.