43. Engineering Hydrogen Generation Sites to Promote Electrocatalytic CO2 Reduction to Formate

Guo, X., Xu, S.-M., Zhou, H., Ren, Y., Ge, R., Xu, M., Zheng, L., Kong, X., Shao, M., Li, Z.*, Duan, H.*
ACS Catal. 2022, 10551-10559.
DOI: 10.1021/acscatal.2c02548

Abstract
Electrocatalytic reduction of carbon dioxide (CO₂ER) to produce formate is an economically viable route for CO₂ upgrading. Bismuth (Bi)-based materials have been recognized as promising catalysts for this reaction but suffer from low activity that hinders their practical applications. Here, we report a cooperative catalyst of silver nanoparticles (Ag NPs) supported on a layered bismuth subcarbonate (Bi₂O₂CO₃; BOC) nanosheet array (Ag/BOC), which achieves a 2-fold higher reaction rate in comparison to pure BOC with a high Faradaic efficiency (FE) of 98% to formate, and the FE is maintained at >85% over a wide potential window from −0.86 to −1.26 V vs RHE. Experimental results combined with theoretical results reveal that Ag accelerates the dissociation of H₂O to supply reactive hydrogen species, which migrate to adjacent Bi sites to accomplish CO₂ reduction with promoted activity. Moreover, we realized coproduction of formate at two poles of a homemade two-electrode flow cell by pairing the CO₂ER (at the cathode) and electrooxidation of glycerol (at the anode), achieving an apparent formate FE of 130% at 2.2 V, as well as a 63% electric energy saving for formate production in comparison with the traditional CO₂ER coupled with the water oxidation reaction.