Progress and Perspectives in Photo- and Electrochemical-Oxidation of Biomass for Sustainable Chemicals and Hydrogen Production

Biomass is recognized as an ideal CO₂ neutral, abundant, and renewable resource substitute to fossil fuels. The rich proton content in most biomass derived materials, such as ethanol, 5-hydroxymethylfurfural (HMF) and glycerol allows it to be an effective hydrogen carrier. The oxidation derivatives, such as 2,5-difurandicarboxylic acid from HMF, glyceric acid from glycerol are valuable products to be used in biodegradable polymers and pharmaceuticals. Therefore, combining biomass-derived compound oxidation at the anode and hydrogen evolution reaction at the cathode in a biomass electrolysis or photo-reforming reactor would present a promising strategy for coproducing high value chemicals and hydrogen with low energy consumption and CO₂ emissions. This review aims to combine fundamental knowledge on photo and electro-assisted catalysis to provide a comprehensive understanding of the general reaction mechanisms of different biomass-derived molecule oxidation. At the same time, catalyst requirements and recent advances for various feedstock compounds are also reviewed in detail. Technoeconomic assessment and life cycle analysis are performed on various feedstocks to assess the relative benefits of various processes, and finally critical prospects are given on the challenges and opportunities for technology development to meet the sustainability requirement of the future global energy economy.