Atomic Layer Deposition of Cu Electrocatalysts on Gas Diffusion Electrodes for CO<sub>2</sub> Reduction
Julia D. Lenef, Si Young Lee, Kalyn M. Fuelling, Kevin E. Rivera Cruz, Aditya Prajapati, Daniel O. Delgado Cornejo, Tae H. Cho, Kai Sun, Eugenio Alvarado, Timothy S. Arthur, Charles A. Roberts, Christopher Hahn, Charles C. L. McCrory, Neil P. Dasgupta
Abstract
Electrochemical reduction of CO 2 using Cu catalysts enables the synthesis of C 2+ products including C 2 H 4 and C 2 H 5 OH. In this study, Cu catalysts were fabricated using plasma-enhanced atomic layer deposition (PEALD), achieving conformal deposition of catalysts throughout 3-D gas diffusion electrode (GDE) substrates while maintaining tunable control of Cu nanoparticle size and areal loading. The electrochemical CO 2 reduction at the Cu surface yielded a total Faradaic efficiency (FE) > 75% for C 2+ products. Parasitic hydrogen evolution was minimized to a FE of ∼10%, and a selectivity of 42.2% FE for C 2 H 4 was demonstrated. Compared to a line-of-sight physical vapor deposition method, PEALD Cu catalysts show significant suppression of C 1 products compared to C 2+, which is associated with improved control of catalyst morphology and conformality within the porous GDE substrate. Finally, PEALD Cu catalysts demonstrated a stable performance for 15 h with minimal reduction in the C 2 H 4 production rate.