Cum laude on understanding catalysts under extreme conditions
Physical chemist Rik Mom developed a revolutionary way to investigate catalysts in action in detail. For this work he received the distinction cum laude during his PhD defence on 29 June.
‘Feeling’ the catalyst
Catalysts speed up chemical reactions, without being consumed themselves. Although they are essential in chemistry and widely used in the industry, scientists still lack proper knowledge of how they exactly work. Therefore, Mom looked at catalysts in action with a technique called scanning tunnelling microscopy (STM) – in which a miniscule metal needle scans the surface of a catalyst. Ground-breaking is that Mom transformed this technique to use it in very harsh conditions: high pressures of aggressive gasses at high temperatures – conditions necessary for chemical reactions.
Mom looked at several major industrial processes, such as the removal of sulphur from gasoline. ‘But using STM to investigate this kind of reactions is like a blind person reading braille: the information is there, but it lacks any colour,’ Mom explains. ‘With STM we can see atoms, but we don’t know what atoms they are. Therefore, I combined STM with X-rays.’ Other researchers showed that this combination could work in vacuum, but Mom is the first to successfully try this combination in a realistic environment. ‘It is a very difficult combination, but we showed as proof of concept that it works.’
‘Best PhD student we ever had’
‘Without any hesitation, we can both state that Rik Mom is the best PhD student that we ever had the pleasure to supervise,’ say supervisor Joost Frenken and co-supervisor Irene Groot in their cum laude proposal. They praise the growing impact of his work: ‘It establishes a milestone in the application of advanced scanning probe techniques to the investigation of catalytic process under actual process conditions.’ They continue: ‘Already at the very start of his PhD, Mom has acted more at the level of a mature postdoc than at that of a PhD student.’
Learning a new language
Currently, Mom is working as a postdoc on producing hydrogen from water at the renowned Max Planck Institute in Berlin. He now works with a technique that renders information about the chemical state of the sample, instead of the structure as in STM. ‘This new technique I got used to pretty fast, but electrochemistry is a whole new world for me. It seems like a new language that I need to get acquainted to. But I’m sure I can get some interesting results,’ he concludes.