Selective Photoelectrocatalytic Glycerol Oxidation to Dihydroxyacetone via Enhanced Middle Hydroxyl Adsorption over aBi2O3-Incorporated Catalyst

Photoelectrocatalytic (PEC) glycerol oxidation offers asustainable approach to produce dihydroxyacetone (DHA) as a valuablechemical, which canfind use in cosmetic, pharmaceutical industries, etc.However, it still suffers from the low selectivity (<= 60%) that substantiallylimits the application. Here, we report the PEC oxidation of glycerol to DHAwith a selectivity of 75.4% over a heterogeneous photoanode of Bi2O3nanoparticles on TiO2nanorod arrays (Bi2O3/TiO2). The selectivity ofDHA can be maintained at similar to 65% under a relatively high conversion ofglycerol (similar to 50%). The existing p-n junction between Bi2O3and TiO2promotes charge transfer and thus guarantees high photocurrent density.Experimental combined with theoretical studies reveal that Bi2O3prefers tointeract with the middle hydroxyl of glycerol that facilitates the selectiveoxidation of glycerol to DHA. Comprehensive reaction mechanism studiessuggest that the reaction follows two parallel pathways, including electrophilic OH*(major) and lattice oxygen (minor) oxidations.Finally, we designed a self-powered PEC system, achieving a DHA productivity of 1.04 mg cm-2h-1with >70% selectivity and a H2productivity of 0.32 mL cm-2h-1. This work may shed light on the potential of PEC strategy for biomass valorization toward value-added products via PEC anode surface engineering.

Automated summary

This study reports a photoelectrocatalytic (PEC) glycerol oxidation method for the production of dihydroxyacetone (DHA) with enhanced selectivity. A heterogeneous photoanode consisting of Bi2O3 nanoparticles on TiO2 nanorod arrays was used, and the selectivity of DHA was increased. Experimental and theoretical studies revealed the interaction between the catalyst and glycerol, as well as the parallel pathways of the reaction. Furthermore, a self-powered PEC system was designed, achieving high productivity of DHA and H2.