Selective Enhancement of Methane Formation in Electrochemical CO₂ Reduction Enabled by a Raman-Inactive Oxygen-Containing Species on Cu

Abstract

The role of oxygen-containing species on Cu catalysts in the electrochemical CO2 reduction reaction (CO2RR) remains unclear due to the difficulty in its stabilization under reaction conditions. Co-electrolysis of CO2 with an oxidant is an effective strategy to introduce oxygen-containing species on Cu during the CO2RR. In this work, we present concrete evidence demonstrating that an oxygen-containing species is able to not only enhance the rate of the CO2RR but also tune selectivities for certain products. Co-electrolysis of CO2 with H2O2 on Cu selectively accelerates the CH4 production rate by up to a factor of 200, but with only a slight enhancement of C2+ products. Combined investigations using in situ Raman spectroscopy with density functional theory calculations reveal that a Raman-inactive Cu oxide species is responsible for the improved CH4 production. Results reported in this work highlight the possibility of enhancing Cu-based CO2RR catalysts by introducing stable oxygen-containing catalytic structures.

Facet Engineering of Copper for Product Specific CO2 Electroreduction

“…This method improves our understanding of the electrocatalytic mechanism. 122 3.1.1. In Situ Surface Investigations.…”

Nanoscale Management of CO Transport in CO2 Electroreduction: Boosting Faradaic Efficiency to Multicarbon Products via Nanostructured Tandem Electrocatalysts

“…In addition, oxygencontaining species are also present in the Raman spectra of Cu needle-Ag (dotted green lines at ≈320, ≈392, and ≈620 cm −1 ; these species do not have a direct correlation with CO 2 RR activity. [59,60] Figure S27 (Supporting Information) shows in situ Raman spectra of Cu particles and Cu needle. No prominent peaks of reaction intermediates were observed in their spectra, indicating that their CC coupling ability is relatively weak.…”

Cu‐Based Catalytic Materials for Electrochemical Carbon Dioxide Reduction: Recent Advances and Perspectives

“…Cu Oxide and Cu Hydroxide Oxidation and/or hydroxidation of the surface of Cu spices were proved to be a feasible process to moderate CRR performance of Cu-based electrocatalysts. [112] For instance, Broekmann et al revealed that the coexistence of Cu and Cu oxide on the activated Cu mesh could alter CRR mechanism and avoid the accumulation of poisoning surface species; consequently, it led to FE of 13% for C 2 H 5 OH and FE of 11.8% for n-PrOH (Figure 10a). [113] It was also reported by Hwang et al that the presence of Cu(OH) 2 on the surface of Cu electrode could effectively regulate the electrochemical reduction environment in CRR, which was critical in the formation of C 2 H 4 as CRR product.…”