An in Situ Study of Bond Strains in 1 nm Pt Catalysts and Their Sensitivities to Cluster-Support and Cluster-Adsorbate Interactions

The electronic and atomic structural properties of nanoscale metal catalysts exhibit complex influences with origins related to particle size, metal support, and metal adsorbate interactions. The experimental investigations of these factors, as well as the elucidation of the impacts they have on mechanisms in catalysis, are hindered by their interdependency in working catalysts. We demonstrate in this work that the features underpinning bond strains and adsorbate-bonding effects in nanometer-scale Pt catalysts supported on both gamma-alumina and carbon can be distinguished and analyzed using combined high-energy resolution fluorescence detection (HERFD) X-ray absorption spectroscopy methods, namely, HERFD XANES and HERFD EXAFS. The work extends insights into the fluxional structural dynamics obtained in these systems, a feature harboring significant consequences for understandings of both their properties and mechanisms of action.