Shape/Crystal Facet of Ceria Induced Well-Dispersed and Stable Au Nanoparticles for the Selective Hydrogenation of Phenylacetylene

Abstract

A series of CeO2 with the morphology of nanocube (NC), nanopolyhedron (NP) and nanorod (NR) were synthesized by hydrothermal method as substrates to support monometallic Au catalysts. Insight into support morphology-dependent the property of active component and catalytic behavior for the selective hydrogenation of phenylacetylene has been performed. Specifically, nanocube ceria could disperse monometallic Au nanoparticles due to a large amount of low coordinated sites that readily generated the strong interaction for anchoring active metal, whereas the polyhedron and rod-like ceria supported Au nanoparticles possessed large size and wide particle distribution. As expected, well-dispersed and stable Au/CeO2 nanocube demonstrated 83% of selectivity towards styrene when the conversion of phenylacetylene reached 90%, which was much higher than that of others. Preferable activity was mainly ascribed to small size of Au nanoparticles, which facilitated the adsorption/dissociation of hydrogen considered as the rate-determining step. Enhanced selectivity was due to the electronic effect that caused by strong interaction between Au and cubic CeO2, which also contributed to good stability. This work not only provides a facile method for the preparation of highly dispersed and efficient Au/CeO2 catalysts by modulating the morphology of support, but also offers a novel idea for the fabrication of other highly dispersed supported metal catalysts with enhanced behavior in heterogeneous catalysis.