Green hydrogen production through a facile aqueous-phase reforming technique from waste biomass: A comprehensive review

Current energy requirements are fulfilled by the combustion of fossil fuels, resulting in various concerns including environmental pollution and the depletion of natural resources. Hydrogen has emerged as a sustainable solution for the current energy crisis and is a potential alternative to fossil fuels. Consequently, modern technologies are being developed to introduce novel options for utilizing renewable energy sources as an alternative for energy generation. The use of waste (lignocellulosic) biomass in the aqueous-phase reforming (APR) process for hydrogen production has provided sustainable solutions. The APR mechanism utilizes different catalysts depending on the type of feedstock used for hydrogen production. Catalyst selection mainly aims to facilitate hydrogen production via C–C bond cleavage and the water-gas shift (WGS) reaction. This review focuses on green hydrogen production from waste biomass via APR. In addition, the economic and commercial feasibility of APR for hydrogen production using different types of biomass waste, development of catalysts for higher selectivity, process integration, optimization of process parameters, and the use of pretreatment processes to increase hydrogen yield are highlighted. The total cost of H₂ production is estimated to be $7.45/kg H₂; therefore, economic feasibility remains a significant challenge for its large-scale implementation. This study is concluded with suggestions for optimizing the process for economical and large-scale hydrogen production.