Selective Hydrogenation of Acetylene over SBA-15 Supported Au-Cu Bimetallic Catalysts

Copper has been reported to be active in selective hydrogenation of acetylene but very selective to oligomers instead of ethylene. In this work, SBA-15 supported Cu-Au bimetallic nanoparticles are studied under different Cu/Au ratios and temperature. The addition of gold promotes the catalytic performance, reducing the amount of oligomers formed on the catalyst's surface. A synergistic effect between copper and gold is also displayed. The bimetallic catalyst with Cu/Au ratio at 1/3 has both better conversion and selectivity between 160-200 degrees C, providing the opportunities to lower the operating temperature (>200 degrees C) of copper. The synergy can be ascribed to the compromise of two factors: the electronic effect and the sintering resistance of bimetallic nanoparticles. Gold makes copper more electron-deficient, therefore, enhances the conversion. Besides, the particles remain highly dispersed and small (ca. 3 nm) when large amount of gold reduces the ensemble size of copper on the surface, minimizing C-C coupling reactions.