Boosting the Volmer step by synergistic coupling of dilute CuRu nanoalloy with Cu/Ru dual single atoms for efficient and CO-tolerant alkaline hydrogen oxidation

Active and poisoning-resistant Ru-based electrocatalysts for the hydrogen oxidation reaction (HOR) are designed and fabricated by integrating Cu/Ru dual single atoms and alloy CuRu nanoparticles (N-(CuRu)_NP+SA@NC) through a strategy involving weak chemical reduction and ammonia-assisted gas-phase nitridation. The resultant N-(CuRu)_NP+SA@NC electrocatalysts feature nitrogen atoms coordinated to both Cu and Ru metal atoms via strong N-metal interactions. Density functional theory calculations revealed that alloyed CuRu nanoparticles and monodispersed Cu atoms are vital for altering the electronic configuration of the host Ru elements. This finely tuned structure enhanced the adsorption of H and OH and promoted CO oxidation over the N-(CuRu)_NP+SA@NC electrocatalyst, resulting in high alkaline HOR activity, as evidenced by the higher exchange current density of 3.74 mA cm^–2 and high mass activity of 3.28 mA μg_Ru^–1, which are far superior to those of most Ru-based catalysts reported to date. Moreover, the N-(CuRu)_NP+SA@NC electrocatalysts are resistant to CO poisoning and can be used at a high concentration of 1000 ppm CO with no distinct decay in the activity, in stark contrast to the commercial Pt/C catalyst under the same conditions.