Non-thermal plasma engineering of CuO/Cu2O nanostructures on copper mesh for tunable selectivity in electrochemical CO2 reduction

Abstract The rising levels of atmospheric CO₂ have exceeded the capacity of the natural carbon cycle, driving interest in electrocatalytic CO₂ reduction as an environmental and energy solution. Copper-based tandem electrocatalysts remain the most investigated catalysts due to their capability to convert CO₂ into a wide range of valuable products. However, such reactions require surface modulation to improve performance. Herein, we modulate the surface electrocatalyst via non-thermal N 2 and CO 2 plasma activation, yielding a well-coated CuO/Cu 2 O surface and creation of superficial defects that enhance electrocatalyst activity for CO 2 reduction to C 2+ products, with a faradaic efficiency greater than 70%, while suppressing hydrogen evolution. Our results demonstrate that CO 2 non-thermal plasma exposure to copper oxide nanostructures promotes greater roughness and creation of new active sites through oxygen vacancy defects, which play a partial role in determining catalytic performance, allowing stabilization of *CO intermediate, promoting the formation of C–C couple reaction and further conversion to C 3 products, we registered in potential − 1.2 V (vs. RHE) enhanced production of C 2+ , mostly acetic acid (35%), ethanol (20%), and propanol (10%). This plasma-assisted method improves CO 2 reduction reaction performance compared to that typically reported with a metallic copper substrate.