Carbon-supported Ni nanoparticles for efficient CO electroreduction.

The development of highly selective, low cost, and energy-efficient electrocatalysts is crucial for CO electrocatalysis to mitigate energy shortages and to lower the global carbon footprint. Herein, we first report that carbon-coated Ni nanoparticles supported on N-doped carbon enable efficient electroreduction of CO to CO. In contrast to most previously reported Ni metal catalysts that resulted in severe hydrogen evolution during CO conversion, the Ni particle catalyst here presents an unprecedented CO faradaic efficiency of approximately 94% at an overpotential of 0.59 V, even comparable to that of the best single Ni sites. The catalyst also affords a high CO partial current density and a large CO turnover frequency, reaching 22.7 mA cm and 697 h at -1.1 V ( the reversible hydrogen electrode), respectively. Experiments combined with density functional theory calculations showed that the carbon layer coated on Ni and N-dopants in carbon material both play important roles in improving catalytic activity for electrochemical CO reduction to CO by stabilizing *COOH without affecting the easy *CO desorption ability of the catalyst.