Analysis of Trends and Emerging Technologies in Water Electrolysis Research Based on a Computational Method: A Comparison with Fuel Cell Research

Abstract

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.

Powering the Hydrogen Economy from Waste Heat: A Review of Heat‐to‐Hydrogen Concepts

“…[43] Typically,aDC power with a voltage in excesso f1 .24 Vi sa pplied between the two electrodes which are immersed in water bath having aqueous electrolyte. [43] Typically,aDC power with a voltage in excesso f1 .24 Vi sa pplied between the two electrodes which are immersed in water bath having aqueous electrolyte.…”

“…The splitting of water is performed by using electrolyzers, which are devicesw itht wo electrodes that use an electric current to split water molecules. [43] Typically,aDC power with a voltage in excesso f1 .24 Vi sa pplied between the two electrodes which are immersed in water bath having aqueous electrolyte. As ar esult, hydrogen evolutiono ccurs at the cathode and oxygen at the anode (Figure1 1).…”

A New Class of Zn1‐xFex–Oxyselenide and Zn1‐xFex–LDH Nanostructured Material with Remarkable Bifunctional Oxygen and Hydrogen Evolution Electrocatalytic Activities for Overall Water Splitting

“…As an alternative, researchers developed earth‐abundant transition‐metal‐based electrocatalysts for OER and HER in alkaline and acid media separately . To carry out overall water splitting, catalysts for both OER and HER should be operated in either a strongly acidic or basic electrolyte to use them in proton‐exchange membrane (PEM) or alkaline electrolyzers, respectively for generating H 2 . But these are challenging for most nonprecious transition‐metal‐based electrocatalysts, because an active alkaline‐OER and acidic‐HER catalyst may be inactive or even unstable in acidic and alkaline media, respectively.…”

“…[10][11][12][13] To carry out overall water splitting, catalysts for both OER and HER should be operated in either a strongly acidic or basic electrolyte to use them in protonexchange membrane (PEM) or alkaline electrolyzers, respectively for generating H 2 . [14][15][16] But these are challenging for most nonprecious transition-metal-based electrocatalysts, because an active alkaline-OER and acidic-HER catalyst may be inactive or even unstable in acidic and alkaline media, respectively. These limitations have initiated and motivated significant research efforts in recent years toward making nonprecious bifunctional The scalable and cost-effective H 2 fuel production via electrolysis demands an efficient earth-abundant oxygen and hydrogen evolution reaction (OER, and HER, respectively) catalysts.…”

“…The elemental composition of nanosheets of Zn 1-x Fe x -LDH, and Zn 1-x Fe x -oxyselenide was examined by high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) and is displayed inFigure 5c,f, respectively.Figure 5cshows the existence of Zn, Fe, and O on the nanosheet of Zn 1-x Fe x -LDH, and the nanosheet of Zn 1-x Fe x -oxyselenide (Figure 5f)shows Se along with the Zn, Fe, and O. Associated energy-dispersive X-ray spectroscopy (EDX) analysis is provided inFigure S2a,b (Supporting Information), Small 2018,14, 1803638…”