Coupling effects of Zn single atom and high curvature supports for improved performance of CO2 reduction

Single-atom catalysts (SACs) have emerged as one of the most competitive catalysts toward a variety of important electrochemical reactions, thanks to their maximum atom economy, unique electronic and geometric structures. However, the role of SACs supports on the catalytic performance does not receive enough research attentions. Here, we report an efficient route for synthesis of single atom Zn loading on the N-doped carbon nano-onions (ZnN/CNO). ZnN/CNO catalysts show an excellent high selectivity for CO2 electro-reduction to CO with a Faradaic efficiency of CO (FECO) up to 97% at -0.47 V (vs. reversible hydrogen electrode, RHE) and remarkable durability without activity decay. To our knowledge, ZnN/ CNO is the best activity for the Zn based catalysts up to now, and superior to single atom Zn loading on the two-dimensional planar and porous structure of graphene substrate, although the graphene with larger surface area. The exact role of such carbon nano-onions (CNO) support is studied systematically by coupling characterizations and electrochemistry with density functional theory (DFT) calculations, which have attributed such good performance to the increased curvature. Such increased curvature modifies the surface charge, which then changes the adsorption energies of key intermediates, and improves the selectivity for CO generation accordingly. (c) 2021 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Automated summary

This study presents an efficient synthesis method for preparing single atom Zn loading on N-doped carbon nano-onions, which exhibit excellent selectivity and stability in CO2 electro-reduction to CO. The increased curvature of carbon nano-onions support has been found to modify the surface charge and improve the selectivity for CO generation by changing the adsorption energies of key intermediates.