Biomass-based hydrogen and fuel cell technologies: A bibliometric review of current trends and future directions

As the world moves towards low-carbon energy systems, interest in fuel cell and hydrogen technologies as important facilitators of deep decarbonisation has increased. In this context, biomass has become a strategically significant renewable feedstock since it may reduce dependency on fossil fuel-based hydrogen generation while supporting the principles of the circular bioeconomy. Despite growing research activity, studies on biomass-based hydrogen and fuel cell technologies remain fragmented across production pathways, application domains, and geographical regions, limiting a coherent understanding of global research evolution. To address this gap, this study presents a comprehensive bibliometric analysis of international research on biomass-based hydrogen and fuel cells published between 2012 and 2024. A total of 172 peer-reviewed publications retrieved from Scopus and Web of Science were systematically analysed using ScientoPy, VOSviewer, and Bibliometrix. The analysis examines publication growth trends, citation structures, collaboration networks, and thematic evolution to map the intellectual landscape of the field. Unlike previous bibliometric reviews that focus on hydrogen or fuel cells independently, this study integrates biomass feedstocks, hydrogen production routes, and fuel cell applications into a unified knowledge framework. The findings reveal a rapid acceleration in research output after 2015, with China, the United States, and several Asia-Pacific and European countries emerging as dominant contributors. Keyword co-occurrence and co-citation analyses indicate a thematic shift from conventional biomass conversion technologies toward integrated biorefineries, microbial fuel cells, and green hydrogen systems. Nevertheless, persistent research gaps are identified in techno-economic assessment, life-cycle sustainability evaluation, infrastructure readiness, and policy coordination, which continue to constrain large-scale commercial deployment. Unlike conventional bibliometric studies that primarily focus on publication trends, this study uniquely integrates bibliometric analysis with critical techno-performance evaluation, including technology readiness level (TRL), hydrogen production efficiency, and techno-economic considerations. This hybrid approach provides a deeper understanding of the relationship between research trends and real-world deployment challenges, offering a novel perspective that bridges scientometric mapping with engineering-based decision-making frameworks. In particular, SDG 7 (Affordable and Clean Energy), SDG 9 (Industry, Innovation and Infrastructure), and SDG 13 (Climate Action) are supported by the results, which also provide direction for researchers, industry stakeholders, and policymakers who want to expedite the shift from laboratory-scale innovation to practical energy implementation. This study further provides a decision-support framework for evaluating biomass-based hydrogen technologies based on techno-performance and deployment readiness. This enables stakeholders to prioritise technologies based on both research maturity and deployment feasibility.