Mesostructure‐Specific Configuration of *CO Adsorption for Selective CO₂ Electroreduction to C₂₊ Products

Abstract

The multi-carbon (C₂₊) alcohols produced by electrochemical CO₂ reduction, such as ethanol and n-propanol, are considered as indispensable liquid energy carriers. In most C-C coupling cases, however, the concomitant gaseous C₂H₄ product results in the low selectivity of C₂₊ alcohols. Here, we report rational construction of mesostructured CuO electrocatalysts, specifically mesoporous CuO (m-CuO) and cylindrical CuO (c-CuO), enables selective distribution of C₂₊ products. The m-CuO and c-CuO show similar selectivity towards total C₂₊ products (≥76 %), but the corresponding predominant products are C₂₊ alcohols (55 %) and C₂H₄ (52 %), respectively. The ordered mesostructure not only induces the surface hydrophobicity, but selectively tailors the adsorption configuration of *CO intermediate: m-CuO prefers bridged adsorption, whereas c-CuO favors top adsorption as revealed by in situ spectroscopies. Computational calculations unravel that bridged *CO adsorbate is prone to deep protonation into *OCH₃ intermediate, thus accelerating the coupling of *CO and *OCH₃ intermediates to generate C₂₊ alcohols; by contrast, top *CO adsorbate is apt to undergo conventional C-C coupling process to produce C₂H₄. This work illustrates selective C₂₊ products distribution via mesostructure manipulation, and paves a new path into the design of efficient electrocatalysts with tunable adsorption configuration of key intermediates for targeted products.