EXAFS study of Pd/Ga2O3 model catalysts of selective liquid-phase hydrogenation of acetylene to ethylene

Model catalysts Pd/Ga2O3 of selective liquid-phase hydrogenation of acetylene to ethylene were prepared by impregnation of β-Ga2O3 with a palladium nitrate solution with following drying and reduction in a hydrogen flow at 200 °C. A part of the samples was then calcined in an argon flow at 200–500 °C. The as-prepared samples were tested in the reaction of selective liquid-phase hydrogenation of acetylene. EXAFS was used to study structure of the catalyst components. Based on the EXAFS data it was found that Pd–Ga alloys present in the subsurface region of Pd particles. The presence of these alloys increases activity and selectivity of catalysts. The alloys are decomposed by calcination in inert atmosphere following decrease in catalytic activity.