Ni/Ni3C Core/Shell Hierarchical Nanospheres with Enhanced Electrocatalytic Activity for Water Oxidation.

Developing efficient and low-cost catalysts with high activity and excellent electrochemical and structural stability toward the oxygen evolution reaction (OER) is of great significance for both energy and environment sustainability. Herein, Ni/Ni3C core/shell hierarchical nanospheres have been in situ synthesized via an ionic liquid-assisted hydrothermal method at relatively low temperature. Ionic liquid 1-butyl-3-methylimidazolium acetate has played multiple roles in the whole synthesis process. Benefiting from the high electrical conductivity, more exposed active sites and the core/shell interface effect, the obtained Ni/Ni3C core/shell hierarchical nanospheres exhibit an outstanding OER performance with lower overpotential, small Tafel slope, and excellent stability. This fundamental method and insights with in situ coupling high conductivity metal support and metal carbide in a core/shell nanoarchitecture by an ionic liquid-assisted hydrothermal method would open up a new pathway to achieve high-performance electrocatalysts toward the OER.