Hollow carbon sphere featuring highly dispersed Co-Nx sites for efficient and controllable syngas electrosynthesis from CO2

Abstract

Electrochemical reduction of CO2 and H2O powered by green electricity provides a sustainable way to produce syngas. However, this reaction still suffers from insufficient syngas selectivity, slow charge kinetic process, and poor controllability of the CO/H2 ratio. In this work, we report a hollow carbon sphere electrocatalyst featuring highly dispersed Co-Nx sites (Co-NHCS-x) for efficient and controllable syngas electrosynthesis. The Co-NHCS-400 sample exhibits a high syngas production rate with a steady CO/H2 ratio (≈1:2) over a wide range of operating potential from −0.6 V to −1.1 V vs. RHE. The variation in synthesis temperature can finely tune the coordination environment of Co-Nx in the catalyst. Consequently, the adsorption behaviors of the CO and hydrogen atoms can be manipulated, allowing for the precise adjustment of CO and H2 proportions in the product gas. The findings are potentially applicable to the exploitation of promising carbon-based electrocatalysts for electrochemical CO2 conversion into syngas.