Efficient Electrochemical Hydrogenation of 5‐Hydroxymethylfurfural to 2,5‐Bis(hydroxymethyl)furan on Ag‐Displaced Nanotextured Cu Catalysts

Abstract

The hydrogenation of 5‐hydroxymethylfurfural (HMF), an important bio‐based platform chemical, to 2,5‐bis(hydroxymethyl)furan (BHMF), a promising building block for polymers, is conventionally conducted at high pressures of H2 in the presence of heterogeneous catalysts. Recently, electrochemical hydrogenation has emerged as a promising process for BHMF production; however, one challenge of this process is to improve the catalytic activity of the electrocatalyst. In this study, a series of AgCu electrocatalysts was prepared by galvanic displacement of Ag on nanotextured Cu particles. A comprehensive characterization of the catalysts was carried out and the effects of electrolysis potential, reaction time, and HMF concentration were investigated. The concentration of AgNO3 solution in which Cu was displaced was found to be a key factor to control the catalyst surface morphology, and the optimal catalyst was shown to have high catalytic activity and excellent stability for the electrochemical hydrogenation of HMF to BHMF.

Ag Electrodeposited on Cu Open‐Cell Foams for the Selective Electroreduction of 5‐Hydroxymethylfurfural

“…Productivity decreases with the accumulated charge, starting from 0.708 mmol h À 1 cm À 2 after 20 C to 0.289 mmol h À 1 cm À 2 at the end of test, due to the decrease of HMF concentration with the reaction time in the batch cell. The same trend is reported in the literature for Ag/ Cu flat electrodes in the reduction of HMF 0.02 M at a similar potential, [7,9] but foam electrocatalysts in this work show a higher productivity for all the accumulated charges. For instance, Roylance et al reported a 0.127 mmol h À 1 cm À 2 productivity at 20 C (37 % HMF conversion and 99 % FE), [7] while the value obtained by Zhang et al is 0.052 mmol h À 1 cm À 2 (28 % HMF conversion and 100 % FE).…”

“…GC‐MS analyses evidence the formation of 5‐methylfurfuryl alcohol and 5‐methylfurfural (Figure S10) and the presence of high molecular products. 5‐methylfurfuryl alcohol has been previously related to the presence of Cu; however, making a comparison between our work and the previous one is not straightforward because herein a larger volume of electrolytic solution is used and the size of the catalyst is different. The formation of dimers and oligomers as by‐products is reported by Roylance et al.…”

“…For instance, Roylance et al reported a 0.127 mmol h À 1 cm À 2 productivity at 20 C (37 % HMF conversion and 99 % FE), [7] while the value obtained by Zhang et al is 0.052 mmol h À 1 cm À 2 (28 % HMF conversion and 100 % FE). [9]…”

“…For real deployment of the HMF electroreduction to BHMF in an industrial application, besides selectivity and faradaic efficiency, the process productivity should be largely increased. The largest productivities reported in the literature are still low for a practical application of the electrochemical process …”

“…The largest productivities reported in the literature are still low for a practical application of the electrochemical process. [7,9] Nano-and macro-structuring largely increases the available surface area and therefore the productivity. Electrodes with nanoporous metal structures (such as Ag displaced nanotextured Cu electrodes, [9] and Pd/VN hollow nanospheres sprayed into a bipolar membrane) are successfully applied in the electrocatalytic hydrogenation of HMF into 2,5-bis (hydroxymethyl)tetrahydrofuran (DHMTHF).…”