In Situ Infrared Spectroscopic Evidence of Enhanced Electrochemical CO₂ Reduction and C–C Coupling on Oxide-Derived Copper

Abstract

The reaction mechanism of CO 2 electroreduction on oxide-derived copper has not yet been unraveled even though high C 2+ Faradaic efficiencies are commonly observed on these surfaces. In this study, we aim to explore the effects of copper anodization on the adsorption of various CO 2 RR intermediates using in situ surface-enhanced infrared absorption spectroscopy (SEIRAS) on metallic and mildly anodized copper thin films. The in situ SEIRAS results show that the preoxidation process can significantly improve the overall CO 2 reduction activity by (1) enhancing CO 2 activation, (2) increasing CO uptake, and (3) promoting C−C coupling. First, the strong *COO − redshift indicates that the preoxidation process significantly enhances the first elementary step of CO 2 adsorption and activation. The rapid uptake of adsorbed *CO atop also illustrates how a high *CO coverage can be achieved in oxide-derived copper electrocatalysts. Finally, for the first time, we observed the formation of the *COCHO dimer on the anodized copper thin film. Using DFT calculations, we show how the presence of subsurface oxygen within the Cu lattice can improve the thermodynamics of C 2 product formation via the coupling of adsorbed *CO and *CHO intermediates. This study advances our understanding of the role of surface and subsurface conditions in improving the catalytic reaction kinetics and product selectivity of CO 2 reduction.

Regulating Reactive Oxygen Species over M–N–C Single-Atom Catalysts for Potential-Resolved Electrochemiluminescence

“…As a result, the d-band center of Cu (−2.57 eV) relative to the Fermi level is between the Fe system (−1.55 eV) and the Ni system (−2.66 eV), indicating its moderate interaction with *OOH and stretching of the O–O bond. The medium adsorption of *OOH in the Cu system is in favor of both partial reservation of O–O bond to produce O 2 ·– and partial breaking O–O bond to produce ·OH. , Therefore, the theoretical calculations provide clear and convincing evidence for the above experiments.…”

Surface Reconstruction of La2CuO4 during the Electrochemical Reduction of Carbon Dioxide to Ethylene and Its Benefits for Enhanced Performance

“…On the other hand, since the presence of the electron-rich layer might also affect the Cu d band center, the center integral interval of the d band was measured at binding energy range of 0–8 eV at different soaking times (0 to 10 h). Based on the XPS valence band spectra, the calculated results were −4.21, −4.56, −4.92, −4.97, and −5.01 eV for the La 2 CuO 4 , Soak-0.5h, Soak-2h, Soak-5h, and Soak-2h samples, respectively.…”

Customizing catalyst surface/interface structures for electrochemical CO2 reduction

“…In situ SEIRAS results indicate that the pre-oxidation process can significantly enhance overall CO 2 RR activity by (a) enhancing CO 2 activation, (b) increasing CO uptake, and (c) promoting C–C coupling. 126 In the future, these techniques need to go for higher temporal/spatial resolutions so as to pursue superior accuracy and precision. For example, X-ray free-electron laser (XFEL) could be employed as the beam source to conduct XAS and IR measurements, which could afford useful information with higher quality within shorter test times than do synchrotron-radiation beam sources.…”