Hydrogen Causes Deterioration of Fuel Cell Performance
Results obtained through joint research by Prof. Se-Ho Kim’s team and Max Planck Institute
Study shows that hydrogen changes chemical composition of catalyst and results in decreased catalytic performance
Selected as cover paper for August issue of ACS Energy Letters

▲ Prof. Se-Ho Kim (left) of Korea University and Prof. Baptiste Gault (right) of Max Planck Institute for Iron Research

The research team led by Professor Se-Ho Kim from the Department of Materials Science and Engineering under the College of Engineering, together with Professor Baptiste Gault’s team at Max Planck Institute, used atomic-scale imaging microscopy to identify the fundamental cause of performance deterioration in the cathode material of hydrogen fuel cells.

Hydrogen is a universal energy source found everywhere and can be stored as renewable energy. However, being the smallest element, hydrogen can easily penetrate materials and sometimes cause hydrogen embrittlement, leading to material degradation. The research on 'Hydrogen's Adverse Effects in Fuel Cell Catalysts,' in which Dr. Su-Hyun Yoo from Imperial College London (the first author) participated, was published in the international journal ACS Energy Letters (IF: 22.0) on July 14 and featured as the cover paper for the August issue.
* Title of paper : Dopant Evolution in Electrocatalysts after Hydrogen Oxidation Reaction in an Alkaline Environment

▲ Cover of ACS Energy Letters

Doping, a commonly used method in the design of fuel cell catalysts, is similar to semiconductor processing. It involves adding small amounts of dopant elements to the fuel cell catalyst to develop superior catalytic properties. However, the 3D distribution of traces of dopant elements in the catalyst is difficult to determine using existing analytical techniques, making it challenging to provide a clear explanation of the role and operating principles of the catalyst. This study employed Atom Probe Tomography (APT) to verify the changes in traces of dopant elements inside the hydrogen fuel cell catalyst.

The research team discovered that during the hydrogen oxidation reaction in the fuel cell cathode material, dopant elements that enhance the catalytic properties during surface adsorption and penetration into the catalyst were being removed from the catalyst. Through quantum mechanics-based first principles simulations, it was revealed that hydrogen was changing the chemical composition of the catalyst, leading to a deterioration of its catalytic properties.

Professor Kim said, “This study elucidated the problems caused by hydrogen fuel itself and the reasons for them, aspects which had not been revealed in the field of hydrogen fuel cell catalysts, and it then proposed solutions to these issues. We look forward to future research on methods to suppress the adverse effects of hydrogen in materials to develop the hydrogen economy.”

▲ Analysis of changes in palladium cathode catalyst particles and boron dopants during hydrogen oxidation reaction using APT




▲ First-principles simulations of dopant element instability in relation to hydrogen adsorption