Light‐Driven C−C Coupling for Targeted Synthesis of CH3COOH with Nearly 100 % Selectivity from CO2

Abstract Targeted synthesis of acetic acid (CH 3 COOH) from CO 2 photoreduction under mild conditions mainly limits by the kinetic challenge of the C−C coupling. Herein, we utilized doping engineering to build charge‐asymmetrical metal pair sites for boosted C−C coupling, enhancing the activity and selectivity of CO 2 photoreduction towards CH 3 COOH. As a prototype, the Pd doped Co 3 O 4 atomic layers are synthesized, where the established charge‐asymmetrical cobalt pair sites are verified by X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectroscopy spectra. Theoretical calculations not only reveal the charge‐asymmetrical cobalt pair sites caused by Pd atom doping, but also manifest the promoted C−C coupling of double *COOH intermediates through shortening of the coupled C−C bond distance from 1.54 to 1.52 Å and lowering their formation energy barrier from 0.77 to 0.33 eV. Importantly, the decreased reaction energy barrier from the protonation of two*COOH into *CO intermediates for the Pd‐Co 3 O 4 atomic layer slab is 0.49 eV, higher than that of the Co 3 O 4 atomic layer slab (0.41 eV). Therefore, the Pd‐Co 3 O 4 atomic layers exhibit the CH 3 COOH evolution rate of ca. 13.8 μmol g −1 h −1 with near 100% selectivity, both of which outperform all previously reported single photocatalysts for CO 2 photoreduction towards CH 3 COOH under similar conditions.