CeNCl‐CeO2 Heterojunction‐Modified Ni Catalysts for Efficient Electroreduction of CO2 to CO

Abstract Renewable‐electricity‐powered electrochemical CO 2 reduction (CO 2 RR) is considered one of the most promising ways to convert exhaust CO 2 into value‐added chemicals and fuels. Among various CO 2 RR products, CO is of great significance since it can be directly used as feedstock to produce chemical products through the Fischer–Tropsch process. However, the CO 2 ‐to‐CO electrocatalytic process is often accompanied by a kinetically competing side reaction: H 2 evolution reaction (HER). Designing electrocatalysts with tunable electronic structures is an attractive strategy to enhance CO selectivity. In this work, a CeNCl‐CeO 2 heterojunction‐modified Ni catalyst is successfully synthesized with high CO 2 RR catalytic performance by the impregnation‐calcination method. Benefiting from the strong electron interaction between the CeNCl‐CeO 2 heterojunction and Ni nanoparticles (NPs), the catalytic performance is greatly improved. Maximal CO Faradaic efficiency (FE) is up to 90% at −0.8 V (vs RHE), plus good stability close to 12 h. Detailed electrochemical tests and density functional theory (DFT) calculation results reveal that the introduction of the CeNCl‐CeO 2 heterojunction tunes the electronic structure of Ni NPs. The positively charged Ni center leads to an enhanced local electronic structure, thus promoting the activation of CO 2 and the adsorption of * COOH.