Abstract
Water electrolysis for hydrogen production has received increasing attention, especially for accumulating renewable energy. Here, we comprehensively reviewed all water electrolysis research areas through computational analysis, using a citation network to objectively detect emerging technologies and provide interdisciplinary data for forecasting trends. The results show that all research areas increase their publication counts per year, and the following two areas are particularly increasing in terms of number of publications: “microbial electrolysis” and “catalysts in an alkaline water electrolyzer (AWE) and in a polymer electrolyte membrane water electrolyzer (PEME).”. Other research areas, such as AWE and PEME systems, solid oxide electrolysis, and the whole renewable energy system, have recently received several review papers, although papers that focus on specific technologies and are cited frequently have not been published within the citation network. This indicates that these areas receive attention, but there are no novel technologies that are the center of the citation network. Emerging technologies detected within these research areas are presented in this review. Furthermore, a comparison with fuel cell research is conducted because water electrolysis is the reverse reaction to fuel cells, and similar technologies are employed in both areas. Technologies that are not transferred between fuel cells and water electrolysis are introduced, and future water electrolysis trends are discussed.
Highlights
Renewable energy has received increasing focus as it is unlimited and does not produce waste
An expensive platinum-group metal would be used; platinum is employed in the hydrogen evolution reaction (HER), as well as polymer electrolyte fuel cell (PEFC), while iridium oxide is used in the oxygen evolution reaction (OER) due to its high reactivity and stability
We performed a comprehensive and objective analysis of all research water electrolysis areas following a computational method based on a citation network
Summary
Renewable energy (such as solar and wind power) has received increasing focus as it is unlimited and does not produce waste. The low energy density can be overcome by transporting renewable energy from a region with surplus power. Rechargeable batteries are not suitable for accumulating and transporting energy as the metals used in batteries are expensive, and the energy density per unit weight is low [3]. Water electrolysis is promising as electricity supplied from renewable energy can be stored as hydrogen, which has high energy density per unit weight (Figure 1a). Hydrogen storage is one of the best methods of accumulating and transporting renewable the energy density per unit weight is low [3]. Water electrolysis is promising as electricity supplied from renewable energy can be stored as hydrogen, which has high energy density per unit weight. Hydrogen storage is one of the best methods of accumulating and transporting renewable energy. SScchheemmaattiicc ooff ((aa)) aa wwaatteerr eelleeccttrroollyyzzeerr;; aanndd ((bb)) aa ffuueell cceellll ((eexxaammpplleess ooff aa ppoollyymmeerr eelleeccttrroollyyttee wwaatteerr eelleeccttrroollyyzzeerraannddaappoollyymmeerreelleeccttrroollyytteeffuueellcceellll,,rreessppeeccttiivveelyly))
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
