Selective Photoelectrocatalytic Glycerol Oxidation to Dihydroxyacetone via Enhanced Middle Hydroxyl Adsorption over a Bi₂O₃-Incorporated Catalyst

Abstract

Photoelectrocatalytic (PEC) glycerol oxidation offers a sustainable approach to produce dihydroxyacetone (DHA) as a valuable chemical, which can find use in cosmetic, pharmaceutical industries, etc. However, it still suffers from the low selectivity (≤60%) that substantially limits the application. Here, we report the PEC oxidation of glycerol to DHA with a selectivity of 75.4% over a heterogeneous photoanode of Bi2O3 nanoparticles on TiO2 nanorod arrays (Bi2O3/TiO2). The selectivity of DHA can be maintained at ∼65% under a relatively high conversion of glycerol (∼50%). The existing p–n junction between Bi2O3 and TiO2 promotes charge transfer and thus guarantees high photocurrent density. Experimental combined with theoretical studies reveal that Bi2O3 prefers to interact with the middle hydroxyl of glycerol that facilitates the selective oxidation of glycerol to DHA. Comprehensive reaction mechanism studies suggest 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–2 h–1 with >70% selectivity and a H2 productivity of 0.32 mL cm–2 h–1. This work may shed light on the potential of PEC strategy for biomass valorization toward value-added products via PEC anode surface engineering.

Tunable Competitive Absorption-Induced Signal-On Photoelectrochemical Immunoassay for Cardiac Troponin I Based on Z-Scheme Metal–Organic Framework Heterojunctions

“…The PEC biosensor was fabricated on a TiO 2 NRs supporting photoelectrode (Figure a) using sequential in situ growth of Zr-MOF and loading of Cu­(II) ions. TiO 2 NRs on a fluorine-doped tin oxide (FTO) substrate were prepared via a hydrothermal method according to the reported literature, and their morphology was examined by scanning electron microscopy (SEM). The as-synthesized TiO 2 NRs revealed a nearly perpendicular nanorod array structure and a smooth wall (Figure b).…”

Photoelectrocatalytic Reforming of Polyol‐based Biomass into CO and H2 over Nitrogen‐doped WO3 with Built‐in Electric Fields

“…Methanol presents a more remarkable inhibition for CO evolution (Figure S21), indicating glycerol is directly oxidized by the holes instead of the * OH derived from water oxidation. [49][50][51] 3-Benzenepropanal was used as a probe molecule to investigate the decarbonylation process in acetonitrile/water solution. The CO evolution rate is the highest in pure acetonitrile and decreased with increasing water content, which further confirms photogenerated holes are responsive for the decarbonylation to CO (Figure S22).…”

Building a bridge from solid wastes to solar fuels and chemicals via artificial photosynthesis

“…Compared with biodiesel (an exemplary liquid fuel), glycerol enables a lowly added value, indicating that it necessitates a further chemical conversion. Generally, an accessible route, namely the conversion of glycerol to value‐added products, has been proposed 30,160,161 …”

“…Generally, an accessible route, namely the conversion of glycerol to value-added products, has been proposed. 30,160,161 Most of current studies have been devoted to converting glycerol into hydrogen. 162 For example, Reddy et al 140 reported Ni(OH) 2 quantum dots decorated on TiO 2 nanotubes for hydrogen generation.…”

“…21,22 Specifically, the solar-to-chemical conversion reactions, including splitting water reaction, CO 2 reduction, and N 2 fixation, have been implemented via semiconductors photocatalysis. [22][23][24][25][26][27] Taking water splitting as an example, [28][29][30] photo-induced electron and hole pairs are excited in bulk via harvesting solar energy, and then migrate to the semiconductor surface to decompose water into hydrogen and oxygen, respectively. Hydrogen has been considered to be a promising candidate for the energy supply due to its reproducible, clean, and efficient advantages.…”