A team of chemists from the Russian Academy of Sciences has discovered that metal atoms, not nanoparticles, are the crucial component in catalysts used for fine organic synthesis. In their study, which was published in the Journal of the American Chemical Society, the researchers used various types of electron microscopy to track a region of the catalyst during a reaction and gain insight into its progress.
Traditionally, there are two primary methods for studying a reaction: observing and measuring the reaction as ingredients are added, or attempting to capture the state of all components before and after the reaction and comparing them. However, neither of these methods is ideal for studying nanoscale reactions. In recent years, chemists have developed a new approach of tracking the action of a single particle during the reaction. While this method has its limitations, the researchers used multiple types of electron microscopy, combined with machine-learning algorithms, to overcome them.
The researchers tested their theories using a carbon substrate embedded with palladium nanoparticles as a catalyst. Through studying the reactions with various electron microscopes and training machine learning algorithms with the results, they were able to track a region of the catalyst as it moved through a reaction. They discovered that individual metal atoms, clusters, and nanoparticles all played a role, but approximately 99% of the catalytic activity was due to the palladium atoms, which comprised just 1% of the palladium mass.