Mapping the Scientific Evolution of Liquid Organic Hydrogen Carrier Research: A Comprehensive Bibliometric and Thematic Analysis

Liquid organic hydrogen carriers (LOHC) have emerged as a promising technology for the safe, efficient, and reversible storage and transportation of hydrogen, offering a viable pathway toward the development of a hydrogen-based economy. Despite the rapid expansion of this research field, a comprehensive understanding of its scientific evolution, intellectual structure, and emerging research directions remains limited. This study presents a comprehensive bibliometric and thematic analysis of LOHC research based on 1140 publications indexed in the Scopus database between 2007 and 2025. Bibliometric indicators, scientific mapping, Bradford’s and Lotka’s laws, thematic evolution, and strategic thematic mapping were performed using VOSviewer and Bibliometrix/Biblioshiny. The results reveal an exponential increase in scientific production after 2016, reflecting the growing global interest in LOHC technologies. Bradford’s law identified a highly concentrated publication landscape dominated by a small core of specialized journals, whereas Lotka’s law demonstrated that scientific production is driven by a limited group of highly productive authors. Keyword network and thematic evolution analyses show a clear transition from fundamental hydrogen storage concepts toward advanced catalyst development, molecular design, quantum chemical calculations, machine learning, techno-economic assessment, and hydrogen transport applications. Strategic thematic mapping further indicates that computational methodologies and sustainability-oriented analyses are becoming emerging drivers of future research. Overall, this study provides a comprehensive overview of the conceptual, intellectual, and thematic evolution of LOHC research while identifying the principal scientific trends and technological opportunities expected to shape the next generation of hydrogen storage systems.