Electrocatalytic Refinery of Biomass-Based 5-Hydroxymethylfurfural to Fine Chemicals

Abstract

Because of depleting fossil-fuel reserves, together with the impacts of climate change, alternative eco-friendly production of high-value chemicals and renewables is needed. Biomass feedstock is of particular research interest. 5-Hydroxymethylfural (HMF) is a versatile precursor that can be converted to high-value chemicals via electrolysis. Reduction generates precursors for ethers, ketones, polyurethanes, polyesters, and polyethers, e.g., 2,5-dihydroxymethylfuran (DHMF) and 2,5-dimethyletrahydrofuran (DHMTHF), together with high-energy-density premium biofuels, e.g., 2,5-dimethylfuran (DMF), 2,5-hexanedione (HD) and 5,5′-bis(hydroxymethyl) hydrofuroin (BHH). Oxidation HMF yields valuable chemical products, including 2,5-diformyl furan (DFF), 5-hydroxymethyl-2-furan carboxylic acid (HMFCA), 2,5-furan dicarboxylic acid (FDCA), and maleic acid (MA) that are precursors/intermediates for the polymer industry and chemical/pharmaceutical production(s). In this review, we 1) report a comparative summary of the electrocatalytic refinery of HMF, both electro-oxidation and electroreduction pathways, 2) appraise advances in HMF electroreduction reaction (HRR) and HMF electro-oxidation reaction (HOR), 3) assess reaction pathways and mechanisms, 4) establish a design for electrocatalysts including selection of metal materials, design of the geometric structure, and electronic structural modifications to boost HRR and HOR activity and selectivity, 5) evaluate the impact of reaction parameters including pH, electrolyte composition, applied potential, and initial substrate concentration on HRR and HOR, and 6) provide a prospect on future electrochemical refinement of HMF. We conclude that an improved understanding of reaction conditions is needed to practically boost selectivity and activity for the electrochemical refinement of HMF. Findings will benefit in design for electrochemistry and eco-friendly chemistry in generating fine chemicals and, therefore, are of interest to researchers and manufacturers.

Water-soluble nickel and iron salts for hydroxymethylfurfural (HMF) and water oxidation: the simplest precatalysts?

“…The subsequent HMF oxidation, however, is influenced by the number of active sites that can be reduced back to Ni(OH) 2 and the intrinsic catalytic activity of the catalyst. 6,36,40,62,65 The enlarged oxidation peak in the forward scan of the HMF containing CVs is consistent with this hypothesis, as NiOOH is reduced to Ni(OH) 2 by HMF several times in the timespan of one CV resulting in multiple oxidations of the same Ni(OH) 2 site enlarging the nickel( ii ) oxidation peak. Contrary to this, the reduction peak in the back scan is less pronounced because the nickel( iii ) is reduced through the indirect HMF oxidation catalytic cycle, rather than the applied potential.…”

“…28,35,54,63,64 Two different mechanisms for the HMFOR have been proposed in the literature, depending on the applied reaction conditions and catalysts (see Fig. S13†) 6,36,40,62,65 (i) indirect oxidation, where the metal acts as a redox mediator that changes its valence state, (ii) and direct oxidation, which is potential dependent and directly oxidises HMF involving Ni III+ δ -O −II+(1− δ ) . Nickel-based catalysts in strongly alkaline electrolytes (pH > 13) are known to favour the indirect oxidation pathway.…”

High‐Surface Area Mesoporous Sc2O3 with Abundant Oxygen Vacancies as New and Advanced Electrocatalyst for Electrochemical Biomass Valorization

“…On the other hand, recently, it has seen a surge of new technological niches in electro-synthesis of FDCA, [26] each one of them potentially looking for a novel and high-performance electrocatalysts set. [10d,19,27] However, searching for new and advanced electrocatalysts is a multi-dimensional problem, where many boxes should be ticked at the same time, for instance the synthesis, the way to exposing enough active sites, optimizing the electronic state of the active sites, continuous improving the catalytic activity by understanding the mechanism to the target reaction, et al As such, the concerted research efforts in this work should contribute to the design and exploitation of new and advanced mesoporous solids for electrochemical applications.…”

Hydrophobic Nanosized H-Beta Catalysis for Biomass Furanic Compound Valorization

“…Given the recent depletion of crude oil reserves and growing concerns about global warming, there is a pressing need to focus on selectively converting renewable biomass into biofuels and fine chemicals. , This shift provides a viable alternative to reducing our reliance on fossil resources. To meet the demand for future transportation fuels and chemicals, it is essential to establish new catalytic processes that efficiently transform biomass into valuable products under competitive conditions .…”