Coupling photocatalytic CO<sub>2</sub> reduction and CH<sub>3</sub>OH oxidation for selective dimethoxymethane production.

Wang, Yixuan; Liu, Yang; Wang, Lingling; Perumal, Silambarasan; Wang, Hongdan; Ko, Hyun; Dong, Chung-Li; Zhang, Panpan et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Currently, conventional dimethoxymethane synthesis methods are environmentally unfriendly. Here, we report a photo-redox catalysis system to generate dimethoxymethane using a silver and tungsten co-modified blue titanium dioxide catalyst (Ag.W-BTO) by coupling CO<sub>2</sub> reduction and CH<sub>3</sub>OH oxidation under mild conditions. The Ag.W-BTO structure and its electron and hole transfer are comprehensively investigated by combining advanced characterizations and theoretical studies. Strikingly, Ag.W-BTO achieve a record photocatalytic activity of 5702.49 µmol g<sup>-1</sup> with 92.08% dimethoxymethane selectivity in 9 h of ultraviolet-visible irradiation without sacrificial agents. Systematic isotope labeling experiments, in-situ diffuse reflectance infrared Fourier-transform analysis, and theoretical calculations reveal that the Ag and W species respectively catalyze CO<sub>2</sub> conversion to *CH<sub>2</sub>O and CH<sub>3</sub>OH oxidation to *CH<sub>3</sub>O. Subsequently, an asymmetric carbon-oxygen coupling process between these two crucial intermediates produces dimethoxymethane. This work presents a CO<sub>2</sub> photocatalytic reduction system for multi-carbon production to meet the objectives of sustainable economic development and carbon neutrality.