Electrocatalytic reduction of CO2 on Ag,S-CuxO/Cu catalyst: synergistic roles of sliver and sulfur heteroatoms

A promising dual-coping Ag,S-Cu x O/Cu foam electrocatalyst was synthesized for CO 2 RR. • The synergistic effect of Ag and S for CO 2 RR toward HCOOH and CH 3 OH was elucidated. • The Ag-S synergistic mechanism governing HCOOH and CH 3 OH formation was revealed. The electrochemical reduction of CO 2 into value-added fuels such as formic acid and methanol presents a promising approach to mitigating climate change, yet it is constrained by the rational design of efficient electrocatalysts and the understanding of structure-efficiency relationships. Here, a highly efficient Ag,S-Cu x O/Cu catalyst was developed via a facile in situ dual-doping strategy, incorporating Ag and S onto pre-oxidized copper foam. Comprehensive multimodal characterization (SEM, EDS, XRD, XPS, AES) and electrochemical measurements (LSV, EIS, GC, 1 H NMR) were conducted to elucidate the catalyst’s structural properties and CO 2 reduction performance. Results indicate that Ag/S dual doping synergistically enhances catalytic activity by reducing solution mass transfer resistance through improved catalyst nanostructures and expanding the electrochemical active surface area (ECSA). Ag incorporation effectively suppresses the competitive hydrogen evolution reaction (HER), while S incorporation lowers charge transfer resistance ( R ct ). Compared with the Cu x O/Cu foam catalyst, the Ag,S-Cu x O/Cu foam catalyst exhibits increased partial current densities for formic acid (HCOOH) and methanol (CH 3 OH) by 17.09 and 5.70 mA·cm −2 , respectively. Furthermore, the reaction pathways for the electrochemical conversion of CO 2 to HCOOH and CH 3 OH are systematically elucidated. This study proposes a dual-doping strategy to achieve sustainable CO 2 electroreduction and delivers fundamental insights into the external parameters that govern the selective formation of high-value products. Download: Download high-res image (142KB) Download: Download full-size image