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 Ni3S2 and Co9S8 (Co9S8@Ni3S2/NF) was designed for H2 production and selective oxidation of HMF into 2, 5-furandicarboxylic acid (FDCA). Benefiting from the merit of metal heterojunction, Co9S8@Ni3S2/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 Co9S8@Ni3S2/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/cm2. The generation rate of H2 and FDCA are as high as 45.6 L/h/m2 and 7.25 mg/h/cm2, corresponding to the Faraday efficiency of ∼100% and 93.0%, respectively. The in-situ Raman and theoretical calculations demonstrated that the electron transfer from Ni3S2 to Co9S8 at heterogeneous interface contributes to the formation of Ni/Co–OOH, which is the active species of HMFOR.