Jing Liu,^a Boyang Zhang,^a Yumeng Fo,^b Wanqing Yu,^a Jie Gao,^a Xuejing Cui,^a Xin Zhou,^b Luhua Jiang*^a

^a Electrocatalysis & Nanomaterial Laboratory, College of Materials Science & Engineering, Qingdao University of Science & Technology, Qingdao 266042, China.

^b College of Environment and Chemical Engineering, Dalian University, Dalian 116622, China.

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 µA cm^-2_Ni, 20% higher than Ni₁₀₀Au₁/C-P and 34% higher than Ni/C, and exceptional durability for 6000 cycles. 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 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.

Keywords: Ni-Au nanodimer; hydrogen oxidation reaction; electrochemical activation; electrocatalyst; durability

*Corresponding authors: luhuajiang@qust.edu.cn (L. Jiang)

https://doi.org/10.1016/j.cej.2023.142692