New insights into lignin electrolysis on nickel-based electrocatalysts: Electrochemical performances before and after oxygen evolution

The production of H-2 via electrolysis seems to be the best alternative to traditional catalytic reforming processes. The electrolysis of lignin allows to produce pure H2 while valorizing a low-price biomass waste with (theoretically) lower energy requirements than water electrolysis. Previous studies were published in the last years dealing with the electrooxidation of lignin on Ni-based catalysts. Ni is a robust non-expensive metal that presents a wide variety of oxidation states and phase transitions. To this date, it is still not completely clear how these states/transitions activate the lignin molecule. The aim of this study is to get more insights into the cleavage of the main chemical bonds present in the complex lignin structure over different Ni oxidation states. A Ni/C catalyst, prepared by the polyol method, was thoroughly characterized and tested for the electro-oxidation of both, lignin and 2-phenoxyethanol, where the latter is a model molecule representative of the quintessential beta-O-4 linkage in lignin. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.