Anchored effect induced electron-deficient sites in Mo-doped CoNi2S4 for electrocatalytic oxygen reduction reaction

Modifying the surface atom and electronic configuration is a key challenge but is of prime importance to improve the electrocatalytic performance. Among a variety of surface reconstruction methods, bridging heteroatom-modified catalysts possess a stable structure and controllable electronic configuration. Herein, this work establishes a surface-modified strategy on the surface of CoNi2S4 via introducing Mo–S bridging. As expected, the oxygen reduction reaction (ORR) activity of Mo–S bridged CoNi2S4 showed an optimal performance with a half-wave potential of 0.802 V, superior to primitive CoNi2S4 and many spinel-based catalyst materials reported recently. Both experimental characterization and density functional theory calculations indicate that the improved ORR performance derives from the more electron-deficient sites and anion vacancies by driving electron transfer between Ni, Co, and S, and thus results in the creation of more active sites. These results propose a new direction of surface reconstruction for optimizing spinel-based electrocatalysts.