Detecting Catalytic Turnover on a Single, Isolated Nanoparticle Under Real Reaction Conditions

Most heterogeneous catalysis occurs on a collective of metal nanoparticles (NPs) in a size range of 3 nm-10 nm. The strong coupling between NP size & shape - and catalytic activity proposed by model studies is impossible to reveal with state of the art catalyst probing using flow reactors loaded with millions of diverse NP and mass-spectrometric detection. Therefore, the true nature of the emerging activity from a single NP will be hidden by ensemble smearing.<br/>In order to lower this benchmark orders of magnitude, we fabricated a novel Micro-Electro-Mechanical System (MEMS) - based electron transparent batch reactor for investigation of catalyzed reactions under real reaction conditions on atomic scale with <i>in-situ</i> transmission electron microscopy (TEM), electron-energy-loss-spectroscopy (EELS) combined with atomic force microscopy (AFM). By introducing a cutting edge protocol for gas tight sealing individual mass selected isolated NPs, deposited with a cluster deposition source, under reaction gas atmosphere, we investigated the decomposition reaction of Ammonia (NH3).<br/>This TEM-transparent reactor design in combination with operando imaging and spectroscopic techniques enables monitoring of the captured gaseous species and determination of leak rates at elevated temperatures up to 500 degree Celsius.The here presented novel catalyst probing scheme improves the detection limit by six orders of magnitude and facilitates new standards by merging experimental obtained reaction substances with model based activity-shape studies.