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Abstract: 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 , and small size-controlled gold nanoparticles are formed after chemical reduction. For the first time, O2 plasma was employed to remove the APTES grafted on the surface of silica for preparing the highly dispersed gold nanoparticles (∼3nm). The results of IR, TGA, XRD, and TEM showed that O2 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 O2 plasma was ascribed to two effects: (1) the small size of the gold nanoparticles supported on silica, (2) the nearly neutral charge on the Au nanoparticle, which is favorable to the activation of hydrogen. [Copyright &y& Elsevier]

The cover picture shows a simple milling‐mediated solid reduction method for fabricating of ultrafine gold catalysts. By solid grinding of the N‐modified SiO2 supported Au precursors with NaBH4, subnanometer‐sized clusters and isolated Au atoms can be facilely obtained by tuning the metal loading. This method establishes a good basis for fundamental understanding the size effect of Au in the hydrogenation of CO2 to formate, and provides a general methodology for supported nano‐catalyst preparation. More details are discussed in the article by Huang et al. on page 329–332. [ABSTRACT FROM AUTHOR]

An effective solvent‐free method based on a solid‐reduction process was developed to fabricate ultrafine gold catalysts. By this method we revealed a strong size‐dependent activity of Au species in which subnanometer‐sized clusters exhibited the best activity in the hydrogenation of CO2 to formate, with a turnover number of up to 9278 over 7 h at 90 °C. [ABSTRACT FROM AUTHOR]