CO2 Electroreduction to CO Using Cu-Supported NiO Catalyst: XPS Evidence of Redox Interaction Between Metal and Support

Abstract

In this study, electrocatalysts comprising copper nanoparticles and nickel oxide (NiO) have been engineered and investigated for their efficacy in the electrochemical reduction of carbon dioxide (CO<inf>2</inf>) to carbon monoxide (CO). The CO production pathway is advantageous due to CO's role as a valuable intermediate in synthesizing various chemicals and fuels, making it a key target for efficient and sustainable CO<inf>2</inf> utilization strategies. Among various concentrations of copper (0.5%, 1%, 2.5%, 5%, and 10%) dispersed over NiO, 1% Cu/NiO system shows the best performance, achieving a Faradaic efficiency of 37%. Electroreduction of CO<inf>2</inf> resulted in the selective production of an industrial fuel, CO. Raman and CO<inf>2</inf>-temperature programmed desorption (TPD) demonstrate the differences between NiO and 1% Cu/NiO, which aid in understanding the catalytic systems better. X-ray diffraction (XRD) analysis conducted before and after the reaction demonstrated structural stability of the catalyst. XPS analysis revealed changes in the elemental concentration before and after the electrochemical reaction. Additionally, the electrocatalytic activity of Cu/NiO was compared with its precursors (Cu and NiO), demonstrating that precursor materials exhibited significantly low activity due to the absence of metal-support interactions. © 2025 Wiley-VCH GmbH.