Abstract
The electrochemical oxidation of lignocellulose and plastic waste has been considered a clean and reliable strategy to produce feedstocks for various chemicals and fuels. In this study, we tackle the challenging selective oxidation of various lignocellulose and mixed biodegradable and bio-nondegradable plastics by targeting the oxidative cleavage of the specific C(OH)-C moiety. A monometallic Ni(O)O-H electrocatalyst was used for valorization of cellulose-based biomass, a series of lignin-based model complexes, lignin-derived secondary alcohols (KA oil), and mixed plastic waste based on the catalyst's O-H bond dissociation free energy. The catalyst performs remarkably well to selectively oxidize cellulose and lignin-based model complexes like HMF and PED with excellent yield at a higher current density of 100 mA cm(-2). Mechanical insights into this reaction were obtained by in situ transmitted light spectroscopy and Raman measurements. The catalyst was also able to oxidize KA oil to adipic acid with 54% yield at a constant current electrolysis of 20 mA cm(-2). Furthermore, plastic waste precursors having a C(OH)-C bond were selectively oxidized using this catalyst, which was further expanded to mixed plastic waste upgradation resulting in the generation of formate and acetate with faradaic efficiencies of 66% and 74%, respectively, and 100% yield in terephthalic acid accompanied by the co-production of hydrogen.