A research team led by Hee-Tak Kim at KAIST, in collaboration with Gisu Doo from KIER, has successfully developed a platinum-free water electrolysis technology as an eco-friendly method for hydrogen production. The study addressed the limitations of proton exchange membrane water electrolysis (PEMWE), which was hindered by the need for costly catalysts and coating materials. By focusing on improving electron transfer efficiency, the researchers identified and controlled catalyst particle size to enhance performance. They discovered that the 'pinch-off' phenomenon was a critical cause of reduced conductivity, leading to the development of catalyst particles with a size of 20 nanometers or larger to ensure an electron pathway and restore conductivity. This breakthrough not only overcomes technical challenges but also reduces the reliance on precious metals like platinum, making hydrogen production more economically viable. The innovative design strategy paves the way for high-efficiency proton exchange membrane water electrolysis systems, marking a significant advancement towards a sustainable hydrogen economy.