کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5426081 | 1395874 | 2007 | 7 صفحه PDF | دانلود رایگان |
The adsorption of acetic acid is studied as a function of gold content by temperature-programmed desorption and reflection-absorption infrared spectroscopy on Au/Pd(1 1 1) alloys formed by depositing 5 ML of gold onto a Pd(1 1 1) surface and heating to various temperatures. For mole fractions of gold greater than â¼0.5, acetic acid adsorbs molecularly and desorbs intact with an activation energy of â¼52 kJ/mol. This acetic acid is present as catemers, where the nature of the catemer is found to depend on gold concentration. When the relative gold concentration is less than â¼0.33, adsorption of acetic acid at 80 K and heating to â¼207 K forms η1-acetate species on the surface. On further heating, these can either thermally decompose to eventually evolve hydrogen, water and oxides of carbon, or form η2-acetate species, where the coverage of reactively formed η2-acetate species increases with decreasing gold concentration in the near surface region.
Journal: Surface Science - Volume 601, Issue 5, 1 March 2007, Pages 1351-1357