In recent years, there has been significant progress in the development of catalysts for hydrogen production. Researchers from Pohang University of Science and Technology (POSTECH) have collaborated on a project that explores the future of catalysts for water electrolysis. This method, which produces hydrogen from water, is considered an environmentally friendly technology that emits no carbon dioxide. However, the use of expensive precious metal catalysts like iridium has hindered the economic feasibility of this process. To address this challenge, scientists are investigating the potential of metal alloys as catalysts. This article will delve into the research conducted by Professor Yong-Tae Kim and Kyu-Su Kim, highlighting their findings and proposing avenues for further research.
Water electrolysis is a commonly used method for hydrogen production, but it faces limitations due to the reliance on precious metal catalysts. Iridium, ruthenium, and osmium are the primary catalysts under scrutiny in water electrolysis catalysis research. Iridium, while stable, exhibits low activity and comes at a high cost. Ruthenium, on the other hand, shows commendable activity and is a more cost-effective alternative to iridium, albeit lacking the same level of stability. Osmium, although prone to dissolution, offers an expanded electrochemical active surface area, leading to enhanced geometrical activity.
Initially, the research team focused on developing catalysts using a combination of iridium and ruthenium. By amalgamating these metals, they successfully preserved the positive attributes of each, resulting in catalysts that demonstrated improvements in activity and stability. Furthermore, catalysts incorporating osmium exhibited high activity due to the expanded electrochemical active surface area achieved through nanostructure formation. These catalysts retained the advantageous properties of iridium and ruthenium.
The experimentation expanded to include all three metals, which resulted in a moderate increase in activity. However, the dissolution of osmium had a detrimental effect on the structural integrity of iridium and ruthenium. Consequently, the agglomeration and corrosion of nanostructures were accelerated, leading to a decline in the balance of catalytic performance.
Based on their findings, the research team identified several avenues for further catalyst research. Firstly, they emphasized the need for a metric that could evaluate both activity and stability simultaneously. The activity-stability factor, introduced by Kim’s research group in 2017, aims to address this need.
Additionally, the team highlighted the importance of retaining superior catalyst properties even after the formation of nanostructures. This is crucial as it enhances the electrochemical active surface area of the electrocatalyst. By carefully selecting candidate materials that synergize effectively when alloyed with other metals, researchers can maximize the performance of catalysts for hydrogen production.
The research conducted by Professor Yong-Tae Kim and Kyu-Su Kim presents a promising direction for the development of catalysts for water electrolysis and hydrogen production. By combining metals such as iridium, ruthenium, and osmium, researchers have achieved catalysts with improved activity and stability. However, challenges regarding the dissolution and structural integrity of certain metals remain. Moving forward, it is crucial to establish a metric that evaluates both activity and stability, retain superior catalyst properties after the formation of nanostructures, and carefully select candidate materials for effective alloying. While specific outcomes such as the development of new catalysts were not presented in this study, the essential considerations for catalyst design pave the way for future advancements in hydrogen production technology.