Tuning Electrochemical CO2 Reduction through Variation in Composition of the Cu–Pd Bimetallic Catalyst: Experimental and Theoretical Investigations

Abstract

In the context of global warming, electrochemical reduction of CO₂ (eCO₂RR) offers a promising route to achieve net-zero carbon emissions by producing value-added products. This study investigates copper–palladium (Cu–Pd) bimetallic catalysts for the eCO₂RR, focusing on product distribution by varying catalyst composition. Cu–Pd catalysts were synthesized and characterized for crystallinity, structure, texture, and morphology. Reactions conducted with Cu–Pd molar ratios (1:1, 2:1, 1:2, 3:1) at −0.6 to −1.6 V vs RHE for 1 h yielded diverse products. A 1:1 Cu–Pd ratio achieved 91% Faradaic efficiency (FE) for formate at −1.6 V, while 2:1 and 1:2 ratios produced acetate with FEs of 58% and 35% at −1.4 V. A 3:1 ratio led to methanol with 38% FE at −1.6 V. XPS analysis revealed the metal oxide/metal interface suppressed hydrogen evolution while facilitating reaction intermediates. Quantum mechanical calculations corroborated experimental results, highlighting potential-dependent product selectivity.