Simultaneous Hydrogen Evolution and Lignin Depolymerization using NiSn Electrocatalysts in a Biomass-Depolarized Electrolyzer

In this paper, we report on our efforts to evaluate NiSn as anode electrocatalysts for simultaneous hydrogen evolution and lignin depolymerization in a biomass-depolarized electrolyzer. Different ratios of NiSn alloys were synthesized through co-electrodeposition of Ni and Sn from a pyrophosphate plating bath. The composition and morphology of the electrocatalysts were evaluated by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), and X-ray powder diffraction (XRD) techniques. Electrochemical measurements were carried out in a typical three electrode-cell system to evaluate electrocatalyst kinetics in 1.0 M NaOH solution. We evaluated the alloys as anode electrocatalysts in a flow-through biomass-depolarized electrolyzer. Gas chromatography-mass spectroscopy (GC-MS) was employed to evaluate the production rates of vanillin as one of the main oxidation products. It was found that using NiSn20% electrode as the anode results in higher electrochemical reaction rates and potentially higher rate of aromatic products.