Carbon dioxide (CO₂) is a major contributor to global climate change [1]. Among emerging strategies to mitigate atmospheric CO₂ emissions, the catalytic electrochemical reduction of CO₂ (eCO₂RR) into value-added chemicals has gained considerable attention [2]. A critical factor in this process is the selection of an appropriate catalyst, which significantly influences product selectivity. Accordingly, extensive research has been devoted to identifying catalysts capable of selectively producing specific target products. Copper has demonstrated a strong propensity for the selective formation of ethylene.
This study investigates the potential of radio frequency (RF) sputtering as a novel technique for fabricating copper-based catalysts aimed at enhancing ethylene production in an H-type electrochemical cell. Key parameters—such as substrate type, film thickness, substrate temperature, and co-sputtering with secondary metals—were systematically varied to optimize catalyst performance. The findings reveal that the RF sputtering method is effective in promoting ethylene generation, achieving a Faradaic efficiency of almost 20% (19.5%) at an applied potential of –2400 mV vs Ag/AgCl. This was observed using a 60 nm copper film sputtered at an RF power of 150 W onto a gas diffusion electrode paper substrate maintained at room temperature [3].