Thermochemical Hydrogen Production from Biomass: A Review of Recent Advances

Thermochemical conversion of biomass offers a promising pathway for renewable H2 production while enabling waste valorization and potentially low-carbon or carbon-negative energy systems. This review critically examines advances in thermochemical H2 production from biomass reported during 2020–2026, with an emphasis on the transition from conventional conversion toward integrated and intensified processes. Pyrolysis and gasification are evaluated alongside emerging routes, including sorption-enhanced conversion, chemical looping, supercritical water gasification (SCWG), and multistage systems. Particular attention is given to the evolution of catalysts and functional materials, including Ni- and Fe-based catalysts, bimetallic systems, biochar-supported materials, CaO-containing catalyst–sorbents, mixed metal oxides, and oxygen carriers. Recent advances in reactor engineering and process intensification are assessed, including staged reactors, electrified systems, membrane-integrated gasification, gas cleaning and H2 purification, continuous operation, and pilot-scale demonstration. The increasing application of machine learning for process prediction, optimization, and real-time monitoring is also examined. Techno-economic and life-cycle studies are critically considered to identify the factors governing production cost, energy efficiency, greenhouse gas emissions, and the potential benefits of carbon capture and storage. Overall, the literature demonstrates a shift from maximizing H2 concentration in individual experiments toward integrated biomass-to-H2 systems emphasizing absolute H2 yield, purity, material durability, energy efficiency, carbon management, and scalability. Future progress requires long-duration materials testing, realistic feedstock evaluation, standardized performance metrics, integrated pilot demonstrations, and harmonized techno-economic and life-cycle assessment to establish commercially viable and environmentally sustainable biomass-derived H2 production.