Mesostructure-Specific Configuration of *CO Adsorption for Selective CO Electroreduction to C Products.

The multi-carbon (C) alcohols produced by electrochemical CO reduction, such as ethanol and n-propanol, are considered as indispensable liquid energy carriers. In most C-C coupling cases, however, the concomitant gaseous CH product results in the low selectivity of C alcohols. Here, we report rational construction of mesostructured CuO electrocatalysts, specifically mesoporous CuO (m-CuO) and cylindrical CuO (c-CuO), enables selective distribution of C products. The m-CuO and c-CuO show similar selectivity towards total C products (≥76 %), but the corresponding predominant products are C alcohols (55 %) and CH (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 *OCH intermediate, thus accelerating the coupling of *CO and *OCH intermediates to generate C alcohols; by contrast, top *CO adsorbate is apt to undergo conventional C-C coupling process to produce CH. This work illustrates selective C 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.