Carbon dioxide electroreduction to C2 products over copper-cuprous oxide derived from electrosynthesized copper complex

TLDR

Efficient electroreduction of CO₂ to multicarbon products in aqueous solution is important but challenging, with low C₂ product efficiency limiting scale‑up. This study reports reducing CO₂ to C₂ products (acetic acid and ethanol) over a 3D dendritic copper‑cuprous oxide composite derived from an electrosynthesized copper complex. The composite’s performance stems from near‑zero contact resistance with the copper substrate, abundant active sites in its 3D dendritic structure, and an optimal Cu(I)/Cu(0) ratio. In KCl aqueous electrolyte, the catalyst achieves 80 % C₂ Faradaic efficiency at −0.4 V vs RHE, with overpotentials of 0.53 V for acetic acid and 0.48 V for ethanol and a current density of 11.5 mA cm⁻².

Abstract

Abstract Efficient electroreduction of carbon dioxide to multicarbon products in aqueous solution is of great importance and challenging. Unfortunately, the low efficiency of the production of C 2 products limits implementation at scale. Here, we report reduction of carbon dioxide to C 2 products (acetic acid and ethanol) over a 3D dendritic copper-cuprous oxide composite fabricated by in situ reduction of an electrodeposited copper complex. In potassium chloride aqueous electrolyte, the applied potential was as low as −0.4 V vs reversible hydrogen electrode, the overpotential is only 0.53 V (for acetic acid) and 0.48 V (for ethanol) with high C 2 Faradaic efficiency of 80% and a current density of 11.5 mA cm −2 . The outstanding performance of the electrode for producing the C 2 products results mainly from near zero contacting resistance between the electrocatalysts and copper substrate, abundant exposed active sites in the 3D dendritic structure and suitable copper(I)/copper(0) ratio of the electrocatalysts.