Sulfur Changes the Electrochemical CO₂ Reduction Pathway over Cu Electrocatalysts

Abstract

Electrochemical CO2 reduction to value‐added chemicals or fuels offers a promising approach to reduce carbon emissions and alleviate energy shortage. Cu‐based electrocatalysts have been widely reported as capable of reducing CO2 to produce a variety of multicarbon products (e.g., ethylene and ethanol). In this work, we develop sulfur‐doped Cu2O electrocatalysts, which instead can electrochemically reduce CO2 to almost exclusively formate. We show that a dynamic equilibrium of S exists at the Cu2O‐electrolyte interface, and S‐doped Cu2O undergoes in situ surface reconstruction to generate active S‐adsorbed metallic Cu sites during the CO2 reduction reaction (CO2RR). Density functional theory (DFT) calculations together with in situ infrared absorption spectroscopy measurements show that the S‐adsorbed metallic Cu surface can not only promote the formation of the *OCHO intermediate but also greatly suppress *H and *COOH adsorption, thus facilitating CO2‐to‐formate conversion during the electrochemical CO2RR.

Indium Metal Oxide Tandem Ag Catalyst toward Highly Selective CO2 Electroreduction to CO over a Wide Potential Window

“…DFT calculations are carried out to investigate the intrinsic property, and all calculation models and detailed data are presented in the Supporting Information (Figures S16−S18 − is highly endergonic and acts as the rate-determining step (RDS). 49 In general, the competing reaction for eCO 2 RR is the HER. The Gibbs free energy of HER is calculated in Figure 5D.…”

“…Additionally, theoretical simulation reveals the thermodynamic feasibility of the surface transport of *CO 2 – , wherein the *CO 2 – intermediate migrates from the In site and subsequently readsorbs on the Ag site. The formation of *COOH from *CO 2 – is highly endergonic and acts as the rate-determining step (RDS) Figure C shows that the Gibbs free energy for the RDS on In 2 O 3 (222)- Ag(111) (0.82 eV) is lower than on Ag(111) (1.62 eV), indicating that it is easier to produce CO on In 2 O 3 (222)-Ag­(111).…”

Review on strategies for improving the added value and expanding the scope of CO2 electroreduction products

“…15, when *CO 2 − binds to the catalyst surface via two oxygen atoms, forming the *OCHO intermediate, the preferential formation of formate is achieved through a proton-coupled electron transfer. 97,105,119,319 If CO 2 binds to the catalyst surface through carbon atom, it can result in the generation of the *COOH intermediate. 52,318,320 Afterward, the *COOH intermediate undergoes a second proton/electron transfer process to transform into a *CO intermediate.…”

Recent advances in dynamic reconstruction of electrocatalysts for carbon dioxide reduction

“…Consequently, this facilitates the CO 2 RR toward formate production. 111 In addition to Cu-based materials, main-group metals also exhibit high activity and selectivity in CO 2 conversion to formic acid/formate. Mai’s group reported the electrochemical reconstruction of Bi 19 Br 3 S 27 pre-catalyst into Bi nanosheets, where edge defect sites coordinated with S promote CO 2 RR selectivity toward formate production.…”