Controlling Hydrogen Activation, Spillover, and Desorption with Pd-Au Single-Atom Alloys
| Autor: | Michail Stamatakis, Andrew J. Therrien, Michael F. G. Mattera, Christopher J. Ivimey, Matthew T. Darby, Angelos Michaelides, Felicia R. Lucci, E. Charles H. Sykes |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Hydrogen
Thermal desorption spectroscopy Chemistry Diffusion Inorganic chemistry chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Catalysis Adsorption Desorption Atom Physical chemistry General Materials Science Density functional theory Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | The journal of physical chemistry letters. 7(3) |
| ISSN: | 1948-7185 |
| Popis: | Key descriptors in hydrogenation catalysis are the nature of the active sites for H2 activation and the adsorption strength of H atoms to the surface. Using atomically resolved model systems of dilute Pd-Au surface alloys and density functional theory calculations, we determine key aspects of H2 activation, diffusion, and desorption. Pd monomers in a Au(111) surface catalyze the dissociative adsorption of H2 at temperatures as low as 85 K, a process previously expected to require contiguous Pd sites. H atoms preside at the Pd sites and desorb at temperatures significantly lower than those from pure Pd (175 versus 310 K). This facile H2 activation and weak adsorption of H atom intermediates are key requirements for active and selective hydrogenations. We also demonstrate weak adsorption of CO, a common catalyst poison, which is sufficient to force H atoms to spill over from Pd to Au sites, as evidenced by low-temperature H2 desorption. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|