Photoelectrochemical Selective Oxidation of Glycerol to Glyceraldehyde with Bi-Based Metal-Organic-Framework-Decorated WO₃ Photoanode

The conversion of glycerol to high-value-added products via photoelectrochemical (PEC) oxidation has emerged as a promising approach for utilizing a sustainable and clean energy source with environmental and economic benefits. Moreover, the energy requirement for glycerol to produce hydrogen is lower than that for pure water splitting. In this study, we propose the use of WO₃ nanostructures decorated with Bi-based metal-organic frameworks (Bi-MOFs) as the photoanode for glycerol oxidation with simultaneous hydrogen production. The WO₃-based electrodes selectively converted glycerol to glyceraldehyde, a high-value-added product, with remarkable selectivity. The Bi-MOF-decorated WO₃ nanorods enhanced the surface charge transfer and adsorption properties, thereby improving the photocurrent density and production rate (1.53 mA/cm² and 257 mmol/m²·h at 0.8 V_RHE). The photocurrent was maintained for 10 h, ensuring stable glycerol conversion. Furthermore, at 1.2 V_RHE, the average production rate of glyceraldehyde reached 420 mmol/m²·h, with a selectivity of 93.6% between beneficial oxidized products over the photoelectrode. This study provides a practical approach for the conversion of glycerol to glyceraldehyde via the selective oxidation of WO₃ nanostructures and demonstrates the potential of Bi-MOFs as a promising cocatalyst for PEC biomass valorization.