Review of Hydrogen Production by Catalytic Aqueous-Phase Reforming

Catalytic aqueous-phase reforming (APR) produces higher quality hydrogen (with less carbon monoxide) and carbon dioxide from weak solutions of bio-carbohydrates in a single reactor at low temperatures. It provides a good opportunity for the effective valorisation of biomass-derived products. It is advantageous than steam reforming because it saves energy by avoiding vaporization of the biofeed and lowers cost by precluding an extra water gas shift reactor. As evident from the numerous published works during the past decade, there is growing academic and industrial interest in the APR process. This review updates recent literature on APR of many biomass surrogates such as glycerol, ethylene glycol, sorbitol, ethanol and glucose. Most works focused on the development of efficient catalysts for selective hydrogen production and they were deliberated comprehensively. Key insights into improved catalysts and reaction conditions were highlighted. New inferences on the thermodynamic, kinetic and reactor engineering aspects of the APR process were analysed too. This thorough appraisal of the current literature, which is hitherto missing, will surely contribute to the development of the next generation of catalysts and reactors for commercial applications of the APR process.