Ni nanoparticles confined by yolk-shell structure of CNT-mesoporous carbon for electrocatalytic conversion of CO2: Switching CO to formate

Abstract

Electrochemical reduction of CO2 (CO2ER) to formate has been a promising route to produce value-added chemicals. Developing low-cost and efficient electrocatalysts with high product selectivity is still a grand challenge. Herein, a novel Ni nanoparticles-anchored CNT coated by mesoporous carbon with yolk-shell structure (CNT/Ni@mC) catalysis was designed for CO2ER. Ni nanoparticles were confined in the cavity between CNT and mesoporous carbon shell and the confined space can be controlled by tuning the amount of silica precursor. The mesoporous carbon shell and confined space are beneficial to charge transmission during CO2ER. In contrast to previous studies, the CNT/Ni@mC catalyst presents selectivity toward formate rather than CO. Electrochemical in situ attenuated total reflection Fourier transform infrared spectroscopy measurements indicate the presence of a COO* intermediate that converts to formate under CO2ER conditions. The well-defined structural feature of the confined space of the Ni-based catalyst for selective CO2ER to formate may facilitate in-depth mechanistic understandings on structural factors that affect CO2ER performance.