CuO as (electro)catalyst for lignin valorization

Abstract

Biorefinery is gaining attention as a way to obtain several high-value products in a green approach. Biomass can be used to obtain fuels, like ethanol. The waste, rich in lignins, can be (electro)chemically transformed into monophenols and other fuels, like hydrogen. This macromolecule has a complex structure and the optimization of (electro)catalysts for its depolymerization is difficult, mainly because the lack of fundamental knowledge. Because of this, we decided to compare thermo and electrochemical catalysis, using identical reaction liquor and catalyst. The products were identified and quantified by GC-FID. Mild oxidative conditions generated more aldehydes, independently if it was under electrochemical conditions or not. To explore eventual mechanistic similarities, we investigated the catalyst by Raman spectroscopy and electronic microscopy. By them, a similar behavior was observed, the particles were less coalesced and the CuO-related bands were narrowed. After, by Mott-Schottky analysis, the oxygen vacancies were identified as the active sites.