Subsurface Oxygen in Oxide-Derived Copper Electrocatalysts for Carbon Dioxide Reduction

Area of Science:

• Electrochemistry
• Materials Science
• Surface Science

Background:

• Electrocatalysts are crucial for efficient carbon dioxide reduction reaction (CO2RR).
• Oxide-derived copper electrocatalysts exhibit remarkable performance in CO2RR.

Purpose of the Study:

• To investigate the role of residual oxygen in nanostructured, oxide-derived copper electrocatalysts.
• To elucidate the mechanism behind the high efficiency of these catalysts in CO2RR.

Main Methods:

• In situ ambient pressure X-ray photoelectron spectroscopy (AP-XPS).
• Quasi in situ electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM).
• Density functional theory (DFT) simulations.

Main Results:

• Substantial residual oxygen was detected in nanostructured, oxide-derived copper, but no residual copper oxide.
• Residual subsurface oxygen alters the catalyst's electronic structure.
• This leads to sites with higher carbon monoxide binding energy.

Conclusions:

• Residual subsurface oxygen is proposed to be key to the high efficiency of oxide-derived copper in CO2RR.
• These sites likely remain stable under reducing conditions, promoting the formation of multicarbon products like ethylene.