Synthesis and Reactivity of Pt Nanoparticles and Nanowires in Aerosol-Derived Silica Templates
Novel catalysts, such as platinum, can be synthesized in spherical mesoporous aerosol silica templates. The mesoporous aerosol silica spheres allow for the diffusion of gas through its pores but may also protect the catalyst from sintering and other poisoning. The aerosol silica templates have torturous pores that are approximately 2.5 nm in diameter that run throughout the entire sphere. A platinum precursor is then added to water with the aerosol silica then stirred to evenly distribute the platinum. Depending on the reduction method, either Pt nanowires or nanoparticles form. For the formation of wires, a ?wet? reduction method was developed at a slow reduction rate. For formation of particles, a ?dry? and slow reduction method was developed. These samples were then characterized by electron microscopes and reactivity tests. From the reactivity tests, oxidation and Chemisorption, it was found that the nanowires were slightly more reactive. Under mild, 220°C, oxidation tests, the aerosol silica has protected the Pt from sintering.