Pioneering a Carbon-Free Path: Novel Catalyst Materials Open New Route to Green Hydrogen Production
A joint research team from KU, Sungkyunkwan University, KIST, and Dongguk University discovered a technical solution to reduce the costs associated with the production of green hydrogen. The research group led by Professor Lee Kwang-yeol of KU, Professor Lee Sang-uck of Sungkyunkwan University, Dr. Yoo Sung-jong of Korea Institute of Science and Technology (KIST), and Professor Jin Ha-neul of Dongguk University developed a positive electrode material for anion-exchange membrane water electrolyzers in the form of a double-walled nanotube structure made of a ternary material consisting of platinum, ruthenium, and phosphorous (PtRuP2).The research team successfully produced a ternary material (PtRuP2) composed of platinum, ruthenium, and phosphorus in the form of a double-walled nanotube by controlling nanoparticles using a new method called anion/cation-exchange. In addition, they used this material as a positive electrode material to optimize anion-exchange membrane water electrolyzers, significantly lowering the unit cost of green hydrogen production compared to commercial platinum- and ruthenium-based catalysts.
The importance of this research has been recognized, with the results published as a back cover article in Advanced Energy Materials (IF 27.8, JCR top 3%), an international journal for energy and materials science. This study was supported by the National Research Foundation of Korea (NRF) and the Korea Institute of Energy Technology Evaluation and Planning (KETEP).
A Korean research team achieved a technological breakthrough that has the potential to significantly reduce the production costs of green hydrogen. Green hydrogen refers to hydrogen produced in an eco-friendly manner without carbon dioxide emissions and is a core technology of carbon-neutral technology. Currently, the majority of hydrogen production is classified as gray hydrogen because carbon dioxide is generated in the production process using natural gas and water vapor. However, green hydrogen, which is produced by water electrolysis using electrical energy, is attracting attention as a method of generating hydrogen without carbon dioxide emissions.
Anion-exchange membrane (AEM) technology is an innovative next-generation water electrolysis technology that combines the advantageous characteristics of alkaline water electrolysis (AEC) and polymer electrolyte membrane water electrolysis (PEM). However, commercialization of this water electrolysis technology is limited due to the low activity and durability of conventional catalysts, so there is an urgent need for price-competitive catalytic materials that facilitate the development of high-performance AEM water electrolysis for green hydrogen production.
The research team successfully produced a ternary material (PtRuP2) composed of platinum, ruthenium, and phosphorus in the form of a double-walled nanotube by controlling nanoparticles using a new method called anion/cation-exchange. They used this material as a positive electrode to optimize AEM-based water electrolyzers, significantly lowering the unit cost of green hydrogen production compared to commercial platinum and ruthenium-based catalysts.
In performance analysis, the developed PtRuP2-based double-walled nanotube catalyst for water electrolysis exhibited a current density of 9.40 A/cm2 in a 2.0 V range, which is the operating voltage of water electrolysis. This is more than 1.7 times higher than the current density of 5.44 A/cm2 achieved by a commercial platinum catalyst, and the proposed catalyst also exhibited long-term durability of about 270 hours or longer.
The research team discovered that Ru and Pt, which are latticized by P anions, are specialized for use in water electrolysis and hydrogen production, respectively, and demonstrated through theoretical analysis and real-time operando XAS experimental analysis that the performance of the catalyst can be maximized by harnessing the synergic effect between the individual atoms within the nanostructure.
Professor Lee Kwang-yeol of KU said, “Our accomplishment is that we controlled the phase and morphology of materials using a completely new method called ion exchange in the development of nanocatalysts, which may be extended to a methodology for developing diverse, excellent nanocatalysts.” Professor Lee also stated, “If we develop various catalysts using this method, it is expected that water electrolysis catalyst technology can be taken to a new level.”