Hollow Carbon Sphere Featuring Highly Dispersed Co-N X Sites for Efficient and Controllable Syngas Electrosynthesis from CO 2

Electrochemical reduction of CO 2 and H 2 O 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/H 2 ratio. In this work, we report a hollow carbon sphere electrocatalyst featuring highly dispersed Co-N x sites (Co-NHCS- x ) for efficient and controllable syngas electrosynthesis. The Co-NHCS400 sample exhibits a high syngas production rate with a steady CO/H 2 ratio (approximate to 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-N x in the catalyst. Consequently, the adsorption behaviors of the CO and hydrogen atoms can be manipulated, allowing for the precise adjustment of CO and H 2 proportions in the product gas. The findings are potentially applicable to the exploitation of promising carbon-based electrocatalysts for electrochemical CO 2 conversion into syngas.