Room temperature O2 plasma treatment of SiO2 supported Au catalysts for selective hydrogenation of acetylene in the presence of large excess of ethylene

Supported gold nanoparticles have been proven to be active in the hydrogenation of the acetylene. In this work, we applied gold nanoparticles supported on silica for the selective hydrogenation of acetylene in excess ethylene that was close to current industrial practices. Amine group surface-functionalized silica was used to absorb the gold precursor AuCl;, and small size-controlled gold nanoparticles are formed after chemical reduction. For the first time, O-2 plasma was employed to remove the APTES grafted on the surface of silica for preparing the highly dispersed gold nanoparticles (similar to 3 nm). The results of IR, TGA, XRD, and TEM showed that O-2 plasma working under mild conditions (room temperature and low pressure) can efficiently remove the organic compounds without causing the aggregation of the gold nanoparticles. The plasma-treated catalyst Au/SiO2 gave excellent low-temperature selective catalytic activity in the hydrogenation of acetylene. The effects of the reduction temperatures on the catalytic performances of the Au/SiO2 were investigated. The enhanced performance of gold nanoparticles supported on silica as pretreated by O-2 plasma was ascribed to two effects: (1) the small size of the gold nanopartides supported on silica, (2) the nearly neutral charge on the Au nanoparticle, which is favorable to the activation of hydrogen. (C) 2011 Elsevier Inc. All rights reserved.