Boosting hydrogen evolution via anodic oxidation of 5-hydroxymethylfurfural in anion exchange membrane electrolyzer over a metallic heterostructure

Coupling electrocatalytic 5-hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) with hydrogen evolution reaction (HER) is capable of potentially enhancing energy efficiency for hydrogen production and converting biomass into high-valued products. Herein, a novel metallic heterostructure based on Ni 3 S 2 and Co 9 S 8 (Co 9 S 8 @Ni 3 S 2 /NF) was designed for H 2 production and selective oxidation of HMF into 2, 5-furandicarboxylic acid (FDCA). Benefiting from the merit of metal heterojunction, Co 9 S 8 @Ni 3 S 2 /NF not only possesses appropriate H∗ adsorption energy , but also promotes the adsorption and desorption process of organic, thus making reaction dynamics for both HER and HMFOR more exceptional. Furthermore, the anion exchange membrane (AEM) electrolyzer with Co 9 S 8 @Ni 3 S 2 /NF as anode and cathode electrodes toward HMFOR and HER only required a low potential of 1.61 V for continuous hydrogen and FDCA production at the initial current density of 50 mA/cm 2 . The generation rate of H 2 and FDCA are as high as 45.6 L/h/m 2 and 7.25 mg/h/cm 2 , corresponding to the Faraday efficiency of ∼100% and 93.0%, respectively. The in-situ Raman and theoretical calculations demonstrated that the electron transfer from Ni 3 S 2 to Co 9 S 8 at heterogeneous interface contributes to the formation of Ni/Co–OOH, which is the active species of HMFOR.