Stepwise chemical-electrochemical cycles for decoupling modular biomass oxidation and hydrogen evolution
Journal
Chemical Engineering Journal
Journal Volume
505
Start Page
158764
ISSN
13858947
Date Issued
2025-02-01
Author(s)
Abstract
Electrochemical biomass oxidation offers a sustainable method for producing high-value chemicals using green electricity, along with the coproduction of H2 fuel through the hydrogen evolution reaction (HER). Typically conducted in alkaline electrolytes to enhance efficiency, these solutions actually lead to significant side reactions in biomass molecules, such as the Cannizzaro disproportionation and self-polymerization. Besides, the negative impact of cathode on biomass during HER, which causes substantial carbon loss, has frequently been overlooked. Our study introduced the utilization of redox reservoirs (RRs) to effectively decouple the half-reactions, allowing for their independent operation. Characterized by a highly positive formal potential, the RR spontaneously performed the 5-hydroxymethylfurfural oxidation reaction (HMFOR) in water (without supporting electrolyte) under open circuit conditions. This approach not only eliminated the need for subsequent purification of final products but also significantly avoided side reactions, even with highly concentrated reactants. In-situ X-ray absorption spectroscopy revealed Ni3+ species within RRs as the active sites for water-based HMFOR, following first-order kinetics. Moreover, the flexibility of RRs was demonstrated by the successful oxidation of furfural, indicating their wide applicability for various organic substrates. © 2024 Elsevier B.V.
Subjects
5-Hydroxymethylfurfural Oxidation
Biomass Conversion
Decoupled Reaction
Electrolyte-Free Reaction
Redox Reservoirs
SDGs
Publisher
Elsevier B.V.
Type
journal article