Scientometric review of transition metal oxides for hydrogen energy production

Hydrogen production from electrocatalytic and photo(electro)catalytic water splitting is regarded as a potential technology for clean energy production and sustainable energy storage, but the implementation is limited by the development of cost-effective and high-activity hydrogen evolution reaction (HER) catalysts. Transition metal oxides, a class of important functional materials with changeable elementary composition and crystal structures, have aroused scientists' attention for the investigation on HER. Under the circumstance, it is necessary to prepare a systematic and comprehensive evaluation of the development in this scientific area and identify the most potential materials, technologies, as well as the existing limitations and opportunities for the future commercialization. In this article, a scientometric study in the scientific area of transition metal oxides for electrocatalytic and photo(electro)catalytic HER was performed. In total, 1447 papers from Web of Science (WoS) database were extracted via the combination of relevant keywords and analyzed using various scientometric indices through Anaconda Prompt, ScientoPy, Citespace combined with Python. The investigation results indicate that the research in this field dated from 1992, and the development in this scientific area greatly accelerated from 2015. The top two types of publications in article and review share 83.8% and 13.4% of all the documents published in this area. Specifically, the most contributed countries in this field are China and United States. Journal of Materials Chemistry A is the most active journal in this scientific area. The analysis of important keywords in this research field hints that nanotechnology should be paid great attention to further promote the development of this area.