Synchronous bio-oil upgrading and CO2 fixation by co-electrolysis

Abstract

Biomass utilization coupled with CO2 fixation offers a promising approach to produce sustainable carbon–neutral biofuels and chemicals while contributing to reducing CO2 emissions. In this study, we proposed a method for synchronous bio-oil upgrading and CO2 fixation by co-electrolysis in a sealed, undivided cell equipped with a metal cathode and a sacrificial anode. Results showed that the reactive components in bio-oil reacted with CO2 during co-electrolysis, enhancing the abundance of the esters and formic acid by 57.2% and 270.2%, respectively. The CO2 fixation rate was enhanced by 4.6% after co-electrolysis of bio-oil and CO2, with the control experiment in the absence of bio-oil. Additionally, the Cu cathode showed superior catalytic activation for upgrading bio-oil and achieving the highest CO2 fixation, owing to its high selectivity for multi-electro transfer products. To summarize, the ketones and the phenolic derivatives in bio-oil could react with CO2 to form organic esters and acids, while the 2–3 rings and heavy components in bio-oil tended to polymerize and generate insoluble products (polymers). Ultimately, we proposed a carbon-negative distributed biomass processing station system and discussed the future perspective on synchronous bio-oil upgrading and CO2 fixation by co-electrolysis in this work.