Selective CO 2 -to-C 2 H 4 Photoconversion Enabled by Oxygen-Mediated Triatomic Sites in Partially Oxidized Bimetallic Sulfide.

Selective CO photoreduction into C fuels under mild conditions suffers from low product yield and poor selectivity owing to the kinetic challenge of C-C coupling. Here, triatomic sites are introduced into bimetallic sulfide to promote C-C coupling for selectively forming C products. As an example, FeCoS atomic layers with different oxidation degrees are first synthesized, demonstrated by X-ray photoelectron spectroscopy and X-ray absorption near edge spectroscopy spectra. Both experiment and theoretical calculation verify more charges aggregate around the introduced oxygen atom, which enables the original Co-Fe dual sites to turn into Co-O-Fe triatomic sites, thus promoting C-C coupling of double *COOH intermediates. Accordingly, the mildly oxidized FeCoS atomic layers exhibit C H formation rate of 20.1 μmol g  h , with the product selectivity and electron selectivity of 82.9 % and 96.7 %, outperforming most previously reported photocatalysts under similar conditions.