Selective C3–C4 Cleavage via Glucose Photoreforming under the Effect of Nucleophilic Dimethyl Sulfoxide

Biomass photorefinery is an ideal concept to help alleviate the current energy crisis and move toward carbon neutrality. Nevertheless, limited by the complex structure and multiple functional groups of biomass and its derivatives, current biomass photorefinery still suffers from inefficient substrate conversion and product selectivity. In this work, we rationally design polymeric carbon nitride (CN) by supramolecular self-assembly coupled with an organic copolymerization process method to convert glucose, a widely used model biomass molecule, into glycerol which is a value-added photorefinery product. This molecularly engineered photocatalyst improves the charge separation efficiency and significantly enhances visible light absorption. Importantly, ∼95% glucose conversion is achieved by the photogenerated reactive species of •O2–, h+, and •OH under mild conditions with selective C3–C4 cleavage via a retro-aldol reaction pathway. The presence of O2 could provide favorable reactive oxygen species during the photoreforming process, and glycerol is the main product with >50% selectivity under the effect of nucleophilic dimethyl sulfoxide (DMSO), which realizes the hydrogenation reaction of 1,3-dihydroxyacetone (DHA) and glyceraldehyde. Our density functional theory (DFT) analysis reveals that DHA is the more favored intermediate compared to glyceraldehyde. This work demonstrates an example of using engineered photocatalysts and reaction systems for selective biomass valorization into biofuels/chemicals via a mild photocatalytic process.