Ternary interfacial superstructure enabling extraordinary hydrogen evolution electrocatalysis

Realizing large-scale electrochemical hydrogen evolution in alkaline and neutral media by robust and non-noble-metal heterogeneous catalysts is highly ambitious due to the sluggish reaction kinetics at low H+ conditions. Herein, highly efficient hydrogen evolution reaction (HER) catalysts, comprising Ni, NiO clusters, and defective carbon, are successfully constructed via a facile and large-scale route. Multiple synchrotron radiation-based X-ray spectroscopic characterizations, combining high-resolution transmission electron microscopy measurements, indicate the formation of ternary interfacial superstructure with intimate interfacial coupling through abundant NiOC bonds. Impressively, the optimized catalyst loaded onto the usual glass carbon electrode exhibits exceptional catalytic activities with overpotentials of 64 and 76?mV to reach 10?mA?cm-2 in 1?M KOH and 1?M phosphate buffer solution (PBS), respectively, representing one of the best non-noble-metal HER electrocatalysts to date. Insights into the metal/oxide interfacial effects through density functional theory calculations reveal that the interface sites could efficiently lower the energy barrier of the rate-determining step (RDS), contributing to the fast reaction kinetics. This work not only provides comprehensive insights into interfacial feature of highly active HER catalysts but also broadens the fundamental understanding of interfacial effects toward HER catalysis.