Balancing *CHO/*CO Intermediate Flux via Carbonyl-Hydroxyl Motif Synergy Enables High-Selectivity Ethanol Electrosynthesis from Dilute CO_<b>2</b>

Abstract

The electrochemical CO₂ reduction reaction (CO₂RR) to ethanol represents a sustainable avenue to close the carbon cycle and produce renewable fuels, yet challenges persist in achieving high selectivity and activity under industrially relevant dilute CO₂ streams. Herein, we realize an efficient ethanol electrosynthesis by coating Cu catalysts with β-hydroxy ketone-based covalent organic polymers (COP_CO+OH), which not only activate CO₂ but also balance the *CHO/*CO flux at the catalyst-electrolyte interface. The COP_CO+OH coated Cu NPs (Cu+COP_CO+OH) exhibits unprecedented FE_EtOH of 54.2% in 0.5 M KHCO₃, with a partial current density of 121.3 mA cm^-2. Crucially, using a dilute CO₂ feedstock (20% CO₂), it retains ∼40.8% FE_EtOH, circumventing energy-intensive CO₂ purification. Through systematic experimental characterizations and density functional theory (DFT) calculations, we elucidate a unique organic motif synergy: carbonyl groups serve as CO₂ activation centers, while adjacent hydroxyl groups boost *H supply for *CO protonation to *CHO intermediates. This unique synergy enables a balanced *CHO/*CO flux, thereby creating an optimal environment favoring asymmetric *CHO-*CO coupling and preferentially stabilizing the *CHCOH intermediate toward ethanol production. Our investigations establish a universal design paradigm to bypass scaling relations in CO₂RR through organic motif synergy, offering atomistic insights into steering complex reaction networks in CO₂ electroreduction.