Ultrafine Nickel Nanoparticles Encapsulated in N-Doped Carbon Promoting Hydrogen Oxidation Reaction in Alkaline Media

Developing low-cost and robust hydrogen oxidation reaction (HOR) electrocatalysts is urgent for anion exchange membrane fuel cells (AEMFCs). Herein, we report an efficient Ni-based catalyst for HOR in alkaline electrolyte, which features an ultrafine Ni nanoparticle (3.7 nm) core and an ultrathin N-doped carbon shell (0.36 nm). The optimized catalyst exhibits both excellent activity (24.4 A g–1Ni @ η = 50 mV and exchange current density of 38 μA cm–2Ni) and superior stability for the HOR. Theoretical calculations reveal that the d-band state of Ni encapsulated in ultrathin N-doped carbon shell is downshifted, with optimal binding energies of OHad and Had, leading to a low limiting energy pathway for HOR.