The Impact of 5‐Hydroxymethylfurfural (HMF)‐Metal Interactions on the Electrochemical Reduction Pathways of HMF on Various Metal Electrodes

Abstract

5‐Hydroxymethylfurfural (HMF), which can be derived from lignocellulosic biomass, is an important platform molecule that can be used to produce valuable biofuels and polymeric materials. Electrochemical reduction of HMF is of great interest as it uses water as the hydrogen source and achieves desired reduction reactions at room temperature and ambient pressure. Hydrogenation and hydrogenolysis are two important reactions for reductive HMF conversion. Therefore, elucidating key characteristics of electrocatalysts that govern the selectivity for hydrogenation and hydrogenolysis is critical in rationally developing efficient and selective electrocatalysts. In this study, combined experimental and computational investigations are used to demonstrate how the adsorption energy of HMF on metal surfaces and the resulting changes in the intramolecular bond lengths of adsorbed HMF directly impact the reduction pathways of HMF. These results make it possible to rationally understand a general trend in the behaviors observed when using various metal electrodes for HMF reduction.

Insights into the Electrochemical Reduction of 5‐Hydroxymethylfurfural at High Current Densities

“…The higher activity of Ni in the HER shifts the onset in the borate electrolyte towards less cathodic potentials (Figure 1). Remarkably, the addition of HMF to the borate buffer does not significantly modify the LSV curve as recently reported for a Ni plate [35] . Despite the absence of the characteristic HMF reduction peak in the voltammogram, the catalyst is active in the reduction of HMF.…”

“…Remarkably, the addition of HMF to the borate buffer does not significantly modify the LSV curve as recently reported for a Ni plate. [35] Despite the absence of the characteristic HMF reduction peak in the voltammogram, the catalyst is active in the reduction of HMF. At À 0.51 V vs. RHE it reaches a 36 % conversion, though the selectivity and FE are largely decreased, 40 and 14 %, respectively (Figure 8).…”

“…[21] However, recent computational studies stated that the differences in the reactivity of Ni and Ag are related to the interaction of the molecule with the metals. [35] A stronger interaction for Ni than for Ag favors the hydrogenolysis and the formation of methyl furfuryl alcohol (MFA), which could explain both the decrease in the conversion and selectivity, since the process consumes 4 e À rather than 2 e À required to form BHMF. Unfortunately, in this work we could not quantify the MFA.…”

A Review on the Critical Role of H2 Donor in the Selective Hydrogenation of 5‐Hydroxymethylfurfural

“…[98] More recently, Lee et al demonstrated HMF-metal interactions on the electrochemical reduction over various metal electrodes (Ti, W, Fe, Co, Ni, Cu, Ag, Cd, and In). [95] The adsorption energy of HMF on the metal surface and the intramolecular bond lengths in HMF were affected by electrode type. More importantly, the selectivity for the hydrogenation and hydrogenolysis of HMF was also determined by HMF-Metal interactions.…”

“…This study elucidated the universal and key factors that affect the selectivity of the HMF hydrogenation, which is favorable for designing more selective electrocatalysts. [95] Utilizing water as a hydrogen source instead of high-cost H 2 gas via ECH for the selective hydrogenation of HMF is a green and sustainable approach that can be carried out under low operating temperatures and pressures. Moreover, the simultaneous oxidation and hydrogenation of HMF can be achieved over paired cells.…”