Electronic metal-support interaction via Ni defect-induced Ru-modified Ni-CeO2 for enhanced hydrogen oxidation activity

The creation of refined surface vacancies, a crucial bridge between theoretical structural studies and catalyst design, has attracted significant attention. Herein, we utilize a MOF pyrolytic derivatization strategy to create monodispersed Ru nanoparticles anchored on Ni-CeO2 mesoporous microspheres with abundant Ni vacancies (Ru/Ni-CeO2). Introducing nickel vacancies in Ru/Ni-CeO2 is conducive to enhancing electrical conductivity and accelerating mass-charge transfer efficiency. As anticipated, the Ru/Ni-CeO2 displays admirable hydrogen oxidation reaction (HOR) electrocatalytic activity with exchange current density (j(0)) and mass activity reaching 3.27 mA cm(-2) and 1.93 mA g(Ru)(-1), respectively, surpassing the values for cutting-edge Pt/C and most recorded Ru-based HOR electrocatalysts. Surprisingly, Ru/Ni-CeO2 demonstrates robust tolerance to 1000 ppm CO, outperforming Pt/C. Integrated analysis suggests that Ni defect-induced directional electron transfer at the Ru/Ni-CeO2 heterointerface arises from a strong electron-metal support interaction (EMSI) effect between Ru and Ni-CeO2. This interaction optimizes the adsorption of H and OH, thereby enhancing HOR behavior.