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

Abstract

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 VRHE). The photocurrent was maintained for 10 h, ensuring stable glycerol conversion. Furthermore, at 1.2 VRHE, 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.

Advancements in catalysts for glycerol oxidation via photo-/electrocatalysis: a comprehensive review of recent developments

“…GLAD was produced selectively (92.6%) with 257 mmol h −1 at 0.8 V RHE and 420 mmol h −1 at 1.2 V RHE production rate with cogeneration of H 2 with 100% faradaic efficiency. 37 At a bias voltage of 0.8 V RHE , N-doped WO 3 demonstrates a glycerol oxidation to CO evolution rate of 88 mmol m −2 h −1 , accompanied by a selectivity of 70%. A split PEC cell featuring an N–WO 3 photoanode and Pt foil cathode consistently generates H 2 at a rate of 237 mmol m −2 h −1 with a purity exceeding 99.99%, along with the production of carbon monoxide at a rate of 45 mmol m −2 h −1 .…”

Recent advances in the selective oxidation of glycerol to value-added chemicals via photocatalysis/photoelectrocatalysis

“…These advantages are beneficial for rational structural modulation for improved light harvesting and charge separation. 49 Lee et al 50 constructed Bi-based metal–organic frameworks (Bi-MOFs) decorated on WO 3 nanostructures as the photoanode for glycerol oxidation with a 93.6% selectivity to GLYAD at 1.2 V vs. RHE. They proposed that Bi-MOF-decorated WO 3 nanorods enhanced the surface charge transfer and adsorption properties.…”