Hierarchical core-shell Ce-doped NiO@MoO2 architecture with Ni 3d-band center modulation for enhanced high-current-density oxygen evolution.

Ce-doped NiO catalyst supported on MoO₂ nanorods (Ce-NiO@MoO₂) was constructed as a high-performance oxygen evolution reaction (OER) electrocatalyst. The introduction of Ce induced the formation of nanoflower-like NiO on the MoO₂ nanorod substrate. Ce doping not only created numerous unsaturated Ni coordination sites with higher oxidation states, serving as active sites, but also strengthened the adsorption of oxygen intermediates by upshifting the Ni 3d band center, thereby reducing the energy barrier of the rate-determining OH* → O* step. Consequently, the Ce-NiO@MoO₂ catalyst exhibited remarkable OER activity, with a low overpotential of 313 mV and outstanding 200-hour stability at 1000 mA cm⁻², which is attributed to unsaturated Ni active sites and promoted charge and mass transfer facilitated by the unique hierarchical structure. These findings highlight the crucial role of Ce doping in improving electrocatalytic performance and offer insights into developing efficient and cost-effective catalysts for large-scale hydrogen production via water electrolysis. [Display omitted] • Ce-NiO@MoO 2 showed excellent OER activity with a low overpotential of 313 mV and outstanding 200-hour stability at 1000 mA cm−2. • Ce doping created numerous unsaturated Ni sites with high OER activity and facilitated Ni2+ to Ni3+ transition. • Ce doping and oxygen vacancies strengthened the adsorption of oxygen intermediates by upshifting the Ni 3d band center. • The hierarchical core-shell structure and low RDS energy barrier synergistically enhanced OER activity at 1000 mA cm−2. [ABSTRACT FROM AUTHOR]