Recent Progress and Perspectives on Functional Materials and Technologies for Renewable Hydrogen Production.

Scientists worldwide have been inspecting hydrogen production routes and showing the importance of developing new functional materials in this domain. Numerous research articles have been published in the past few years, which require records and analysis for a comprehensive bibliometric and bibliographic review of low-carbon hydrogen production. Hence, a data set of 297 publications was selected after filtering journal papers published since 2010. The search keywords in the Scopus Database were "green hydrogen" and "low carbon hydrogen production and materials". The data were analyzed using the R Bibliometrix package. This analysis made it possible to determine the total annual publication rate and to segregate it by country, author, journal, and research institution. With a general upward trend in the total number of publications, China was identified as the leading country in research on the subject, followed by Germany and Korea. Keyword analysis and the chronological evolution of several important publications related to the topic showed the focus was on water splitting for low-carbon H₂ production. Finally, this review provides future directions for technologies and functional materials for low-carbon hydrogen production.