Influence of electrolyte and pH value on the photoelectrochemical oxidation of 5-hydroxymethylfurfural using mesoporous tungsten oxide photoanodes

Title data

Mayer, Lukas Max ; Bauer, Ines ; Wölfel, Julia P. ; Hahn, Frank ; Marschall, Roland:
Influence of electrolyte and pH value on the photoelectrochemical oxidation of 5-hydroxymethylfurfural using mesoporous tungsten oxide photoanodes.
In: Carbon Future. (June 2026) .
ISSN 2960-0421
DOI: https://doi.org/10.26599/CF.2026.9200078

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Abstract in another language

Photoelectrochemical (PEC) water splitting is a promising strategy for providing clean, sustainable fuel. However, its efficiency is limited by the high overpotential and sluggish kinetics of the oxygen evolution reaction. To improve oxidation kinetics and produce a higher-value product, it is possible to oxidize organic molecules instead. One such molecule is 5-hydroxymethylfurfural (HMF), which can be converted into the high-value platform chemical 2,5-furandicarboxylic acid (FDCA). In this study, we used porous tungsten oxide (WO₃) photoanodes to oxidize HMF photoelectrochemically. Our work focuses on electrolyte selection for this conversion reaction, and we therefore conducted a detailed reproducible study. Furthermore, we carried out a mechanistic investigation and studied the capability of oxidizing the reaction intermediates to support our electrolyte choice. Using the most suitable electrolytes in a self-designed flow-cell setup enabled us to produce FDCA (0.02 mM) for the first time using WO₃ photoanodes under AM 1.5 G illumination. Due to the identification of the side products maleic and formic acid, this work also provides knowledge for further optimization of PEC HMF oxidation.