Coordination-tailored atomic interfaces for selective CH<sub>4</sub>-to-C<sub>2</sub> conversion in aqueous solution.

Bu, Fanle; Yan, Jiayu; Qi, Lu; Zhao, Shuya; Xue, Yurui · Nat Commun · 2025

basic_science · Level V

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Abstract

Selective CH<sub>4</sub>-to-C<sub>2</sub> oxygenates conversion under mild conditions represents a frontier challenge in catalysis science with promising commercial implications. Herein, we report the successful and controlled construction of densely distributed O<sub>2</sub>-bridged Fe diatomic (Fe<sub>1</sub>-O<sub>2</sub>-Fe<sub>1</sub>) interfaces in carbon nitride aerogel-supported Fe dual-atom catalysts (Fe-DAC/g-C<sub>3</sub>N<sub>4</sub>) for selective methane oxidation to acetic acid (CH<sub>3</sub>COOH) in aqueous solution under mild conditions. Experimental studies reveal that the Fe<sub>1</sub>-O<sub>2</sub>-Fe<sub>1</sub> atomic interfaces with tailored coordination environments and precisely modulated Fe-Fe distance (2.92 ± 0.05 Å) and oxygen-bridged coordination environment synergistically promote the activation and cleavage of C-H bond to form methyl radicals (•CH<sub>3</sub>), carboxyl intermediates (•COOH), followed by selective C-C coupling via a radical recombination pathway. This concerted mechanism achieves unprecedented performance with near 100% selectivity and a remarkable CH<sub>3</sub>COOH production rate of 0.79 mmol g<sub>cat</sub><sup>-1</sup> h<sup>-1</sup> under ambient conditions. Notably, industrially relevant pressures (1.5 MPa CH<sub>4</sub>) elevate the production rate to 1.67 mmol g<sub>cat</sub><sup>-1</sup> h<sup>-1</sup> while maintaining >96% selectivity.