Synthesis and Characterization of Platinum Nanoparticle Catalysts Capped with Isolated Zinc Species in SBA-15 cChannels: The Wall Effect

The strong directing effects and difficulties in the removal of organic based surfactants makes the templated synthesis of nanoparticles in solid porous structures of defined molecular sizes such as SBA-15, without the use of surfactants, considerably attractive. However, the effects of their internal surface structures, adsorption affinities, and lattice mismatch on the particle morphology grown therein have not been fully appreciated. Here, we report the internal surface of the silica preferentially hosts isolated tetrahedrally coordinated oxidic Zn species on the molecular walls of the SBA-15 channels from wet impregnated Zn2+ and Pt2+ species. This leads to a less thermodynamically stable but kinetically controlled configuration of atomic zinc deposition on core platinum nanoparticles with unique confined lattice changes and surface properties to both host and guest structures at the interface upon reduction of the composite. This method for the formation templated nanoparticles may generate interest ...