Scientists have discovered why platinum is the most effective material for safely eliminating hydrogen leaks. Research using machine learning revealed the atomic mechanisms of this reaction.
An international team of scientists from Japan and South Africa conducted computer simulations to understand which metals are best suited for the safe use of hydrogen. Hydrogen fuel is promising, but dangerous due to possible leaks and the formation of an explosive mixture with air.
To prevent accidents, special devices are used – passive autocatalytic recombiners (PAR). They contain a safe combination of hydrogen and oxygen to form water. Typically, expensive platinum is used as a catalyst in steam. The researchers’ goal was to understand why this metal is so effective and to find possible alternatives.
Scientists simulated the behavior of nanoparticles of five metals: platinum, palladium, copper, silver and gold. For this purpose, the molecular dynamics method was used based on the universal neural network potential, which made it possible to observe the reaction on the catalyst surface in real time.
The results showed that platinum has a unique balance of properties. Its surface holds oxygen molecules quite firmly, but not too tightly, so they do not immediately disintegrate into atoms. At the same time, the hydrogen atoms on platinum remain mobile and easily react. This provides the optimal path for converting oxygen and hydrogen into water.
Other metals turned out to be less effective. Palladium binds both gases too strongly, copper overly actively splits oxygen and becomes covered with its atoms, and silver and gold, on the contrary, weakly retain reagents on their surface.
The research not only explained platinum’s superiority, but also pointed the way to more affordable materials. Understanding the reaction mechanisms will allow the development of alloys with low platinum content or modified palladium, which will reduce the cost of safety systems for hydrogen energy.
Source: Global Energy
Image: Global Energy
