Rational Design of Single Molybdenum Atoms Anchored on N-Doped Carbon for Effective Hydrogen Evolution Reaction.

The highly efficient electrochemical hydrogen evolution reaction (HER) provides a promising pathway to resolve energy and environment problems. An electrocatalyst was designed with single Mo atoms (Mo-SAs) supported on N-doped carbon having outstanding HER performance. The structure of the catalyst was probed by aberration-corrected scanning transmission electron microscopy (AC-STEM) and X-ray absorption fine structure (XAFS) spectroscopy, indicating the formation of Mo-SAs anchored with one nitrogen atom and two carbon atoms (Mo1 N1 C2 ). Importantly, the Mo1 N1 C2 catalyst displayed much more excellent activity compared with Mo2 C and MoN, and better stability than commercial Pt/C. Density functional theory (DFT) calculation revealed that the unique structure of Mo1 N1 C2 moiety played a crucial effect to improve the HER performance. This work opens up new opportunities for the preparation and application of highly active and stable Mo-based HER catalysts.