Key Words:ALLOY ELECTROCATALYSTS; EVOLUTION; NANOPARTICLES; CATALYST

Abstract:Ni-based nanomaterials are currently the most promising electrocatalysts for the alkaline hydrogen oxidation reaction (HOR), yet limited by their poor electrochemical stability. Herein, we report a nickel-gold nanodimer (Ni100Au1/C-P) synthesized via a galvanic replacement reaction, which via an electrochemical activation mostly transforms into highly dilute gold-in-nickel host nanoalloys (Ni100Au1/C-EA). The Ni100Au1/C-EA exhibits both a remarkable specific HOR activity of 47.3 mu A cm-2Ni, 20% higher than Ni100Au1/C-P and 34% higher than Ni/C, as well as exceptional stability for 6000 cycles and CO-tolerance. Membrane electrode assembly tests further identify the practical application of Ni100Au1/C-EA, which delivers a power density of 192 mW cm-2 and good durability. Theoretical studies suggest that the formation of NiAu alloys is thermodynamically favored with the help of adsorbed hydrogen intermediates. The in situ-formed NiAu nanoalloy, with a lower d band center than Ni, is endowed with improved anti-oxidation ability and appropriate intermediate binding energy, leading to a robust and excellent HOR performance. This electrochemical activation route provides a straightforward and novel strategy for regulating the microstructure of materials and therefore the catalytic activity and endurance of catalysts.

Volume:464

Issue:

Translation or Not:no