Electrochemical reduction of carbon dioxide to produce formic acid coupled with oxidative conversion of biomass

Electrochemical reduction of CO2 (CO2RR) has become a research hot spot in recent years in the context of carbon neutrality. HCOOH is one of the most promising products obtained by electrochemical reduction of CO2 due to its high energy value as estimated by market price per energy unit and wide application in chemical industry. Biomass is the most abundant renewable resource in the natural world. Coupling biomass oxidative conversion with CO2RR driven by renewable electricity would well achieve carbon negativity. In this work, we comprehensively reviewed the current research progress on CO2RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added products. Sn- and Bi-based electrocatalysts are discussed for CO2RR with regards to the structure of the catalyst and reaction mechanisms. Electro-oxidation reactions of biomass derived sugars, alcohols, furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction (OER) in the conventional electrolysis process. It was recommended that to further improve the efficiency of the coupled system, future work should be focused on the development of more efficient and stable catalysts, careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.