Carbon-supported Ni nanoparticles for efficient CO₂ electroreduction

Abstract

The development of highly selective, low cost, and energy-efficient electrocatalysts is crucial for CO₂ 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 CO₂ to CO. In contrast to most previously reported Ni metal catalysts that resulted in severe hydrogen evolution during CO₂ 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^-2 and 697 h^-1 at -1.1 V (<i>versus</i> 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 CO₂ reduction to CO by stabilizing *COOH without affecting the easy *CO desorption ability of the catalyst.