(560hq) Synthesis of Supported Metal Nanoparticles By Controlling the Interaction between Colloidal Metal Nanoparticles and Supports
Supported metal nanoparticles (NPs) represent a large category of heterogeneous catalysts for the fuel and chemical industry. Considerable amount work has been devoted to the synthesis and characterization of supported metal NPs. Industrial methods for the synthesis of supported metal NPs include impregnation and precipitation of molecular precursors followed by calcination and reduction, which often yield polydispersed NPs. Deposition-precipitation, ion exchange, electrostatic adsorption, photodeposition, surface reduction, surface organometallic chemistry, and atomic layer deposition have been developed for the synthesis of supported metal NPs with improved uniformity. These methods heavily hinge on the surface properties of catalyst supports, such as charges, defects, and reactivity of surface hydroxyls. Therefore, they cannot be simply extended to different types of supports.
In this presentation, we will discuss a new protocol to deposit colloidal metal NPs onto various catalyst supports by tuning the interaction between colloid metal NPs and supports. This approach is applicable to many types of metal NPs and supports, and can be readily scaled up without affecting the dispersion of NPs. The metal loading can be adjusted by changing the ratio between metal NPs and supports. Furthermore, the adsorption of colloidal NPs mostly occurs on the external surface of catalyst supports, thus eliminating the diffusion control in catalytic reactions. The Pd catalysts synthesized via our strategy show much lower alkane selectivity in competitive acetylene hydrogenation.