Engenharia de nanoestruturas de óxido de cobre via plasma não térmico para redução eletroquímica de CO2

Abstract

ENGINEERING OF COPPER OXIDE NANOSTRUCTURES VIA NON-THERMAL PLASMA FOR THE ELECTROCHEMICAL REDUCTION OF CO2 investigated the development and optimization of nanostructured electrocatalysts based on copper and CuOx/ZnO, employing defect engineering and structural modification via radio-frequency non-thermal plasma, while evaluating the impact of different gaseous atmospheres. The results demonstrate that post-synthesis modifications on CuOx over metallic mesh optimized the catalytic interface and favored the formation of C2+ products, achieving Faradaic efficiencies (FE) greater than 70%. However, these modulations were limited to the catalyst surface, proving ineffective for suppressing the hydrogen evolution reaction and for the robust propagation of carbon chains. The application of non-thermal plasma treatment prior to the anodization step induced profound structural modifications that extended to the material's bulk, creating preferential nucleation sites. This resulted in a decrease in hydrogen formation rates (FE≤ 25%) and directed C-C coupling routes depending on the gaseous atmosphere. Thus, N2 plasma favored selectivity for n-propanol (FE= 14%), while CO2 plasma stabilized ketones (FE= 7%) and conferred notable integrity to the film. The methodological expansion to CuO/ZnO heterostructures proved that CO2 plasma acts beyond oxidation, serving as an efficient promoter of atomic diffusion and structural consolidation. The controlled incorporation of zinc induced electronic modulation, increasing the electrochemically active surface area, significantly suppressing hydrogen reduction (FE = 11%), favoring the alcohol formation route, primarily ethanol (FE ≥ 25%). Adjusting the plasma exposure time allowed for switching the predominant selectivity between C3 and C2 products. In summary, this work establishes that the synergy between the choice of support, controlled bimetallic integration, and defect induction via non-thermal plasma represents a robust and innovative approach for the rational design of selective catalysts.