Switching between HCOOH and CO in electrochemical CO2 reduction by doping Cu into Cd(OH)2 catalysts

Abstract

Electrochemical CO₂ reduction to value-added chemicals or fuels offers a dual solution to carbon emission mitigation and energy scarcity. Despite the variety of products from electrochemical CO₂ reduction reactions, selectively converting between desired products on analogous materials is challenging. Doping with foreign metals has emerged as a pivotal strategy to optimize catalyst performance and tailor product selectivity. Herein, we synthesize atomically dispersed Cu-doped Cd(OH)₂ catalysts that exhibit enhanced electrochemical performance, notably shifting selectivity from HCOOH to CO. At −0.8 V versus reversible hydrogen electrode (RHE), pure Cd(OH)₂ shows a 75.2% selectivity for HCOOH, whereas the Cu-Cd(OH)₂-3 catalyst achieved a remarkable 97.7% selectivity for CO under identical conditions. Experimental analyses, corroborated by density functional theory (DFT) calculations, reveals that Cu doping facilitates *CO₂ adsorption, enhancing reaction kinetics and reducing the energy barrier for *COOH intermediate formation. This work not only deepens the understanding of metal doping effects in CO₂ electroreduction catalysts, but also provides a viable strategy for the design of electrocatalysts with efficient and controlled selective conversion.