Coupling photocatalytic CO2 reduction and CH3OH oxidation for selective dimethoxymethane production

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 CO₂ reduction and CH₃OH 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⁻¹ 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 CO₂ conversion to *CH₂O and CH₃OH oxidation to *CH₃O. Subsequently, an asymmetric carbon-oxygen coupling process between these two crucial intermediates produces dimethoxymethane. This work presents a CO₂ photocatalytic reduction system for multi-carbon production to meet the objectives of sustainable economic development and carbon neutrality.

This study unravels the efficient photocatalytic route for synthesizing dimethoxymethane by coupling CO2 reduction integrated with CH3OH oxidation by using a silver and tungsten comodified blue titanium dioxide catalyst under mild conditions.