Tailoring *H Intermediate Coverage on the CuAl2O4/CuO Catalyst for Enhanced Electrocatalytic CO2 Reduction to Ethanol

We propose a *H-intermediate-mediating strategy for ethanol electroproduction from CO₂RR. The findings reveal that the in situ generated CuAl₂O₄ in Cu-based catalyst could accelerate water dissociation and tailor *H intermediate coverage, which favors hydrogenation of the *HCCOH to ethanol. This study directs a feasible avenue for mediating *H intermediate coverage and tailoring *H-involved reduction reaction pathways on an efficient and durable Cu-based oxide catalyst.

Abstract

The direct electrochemical conversion of CO₂ to multi-carbon products offers a promising pathway for producing value-added chemicals using renewable electricity. However, producing ethanol remains a challenge because of the competitive ethylene formation and hydrogen evolution reactions. Herein, we propose an active hydrogen (*H)-intermediate-mediating strategy for ethanol electroproduction on a layered precursor-derived CuAl₂O₄/CuO catalyst. The catalyst delivered a Faradaic efficiency of 70 % for multi-carbon products and 41 % for ethanol at current density of 200 mA cm⁻² and exhibited a continuous 150 h durability in a flow cell. The intensive spectroscopic studies combined with theoretical calculations revealed that the in situ generated CuAl₂O₄ could tailor *H intermediate coverage and the elevated *H coverage favors the hydrogenation of the *HCCOH intermediate, accounting for the increased yield of ethanol. This work directs a pathway for enhancing ethanol electroproduction from CO₂ reduction by tailoring *H intermediate coverage.

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