A microreactor in an electron microscope It was already known that catalysts made of metal nanoparticles work well. But the open question was what exactly happens to the individual metal nanoparticles during the catalytic reaction. Alexander Genest from the TU Wien team, who was previously affiliated to the A*STAR High Performance Computing Centre in Singapore, has kept the collaboration between TU Wien and Singapore alive over the years. “Using computational modeling, we had previously looked into Pd nanoparticle oxidation and CO oxidation, so that the extension to methane oxidation was a very promising target”, says Alexander Genest. “The palladium dehydrogenates methane to carbon and hydrogen, while the palladium oxide oxidizes the carbon to CO.” This means that the most efficient catalysis can take place solely at the boundary regions between palladium and palladium oxide.