Investigations Of Supported Platinum Metal Particles

As the most promising materials in the 21th century by the USA material institute, nanomaterials reveal wide prospects in electronics, catalysis, electro-catalysis, laser, luminescence, photoelectricity change, magnetic record, molecule identifying mark and biography sensor, superconductivity, battery, as well as compound material, owing to their unique surface effect, small dimension effect, quantum dimension effect, macroscopic view quantum dimension effect.Template directed growth has been regarded as a well-known approach for effective synthesis and structure control of micro/nano materials since it was firstly applied in nanomaterials synthesis by Martin. By coupled with electrodeposition, template technique is proving a direct and simple way to obtain diversely dispersed metal particles due to its simple operation, high purity of deposits, and easy control of the particle-size.In this contribution, three types of templates were constructed and used to confine platinum (Pt) metal catalyst loading by electrodeposition. Well dispersed platinum nanoparticles with improved electrocalalytic activity to small organic molecules electrooxidation were obtained in these studies. Scanning electron microscopy (SEM), X-ray diffraction (XRD) was applied to investigate the structure and morphology of Pt deposits. Cyclic voltammetry (CV) was used to evaluate the activity of Pt catalyst to small organic molecules electrooxidation. The following aspects were mainly contained:1. Well-dispersed self-assembled carbon was prepared by exfoliation of large aggregates of a novel mesoporous carbon material. Electrostatically self-assembled carbon films interlaced with cationic polyelectrolyte binding layer were constructed and used to confine the growth of Pt metal catalyst. Regular dispersion of Pt metal particles with remarkable activity towards electrooxidation of small organic molecules was obtained by electrodeposition.2. Ordered self-assembled gold nanoparticles films were constructed on conductive surfaces by layer-by-layer technique and used for Pt metal electrodeposition. Effects of electrodeposition potential and deposition time on Pt metal loading as well as activity towards electrooxidation of small organic molecules were investigated. Regular dispersion of Pt metal particles with improved activity towards electrooxidation of formic acid was obtained on the self-assembled gold films, due to the facilitated electrodeposition and directed growth of Pt metal particles on the self-assembled gold template.3. Mesoporous silica SBA-15 was a novel molecular sieve material consisting of hexagonal array of uniformly sized cylindrical pores. In the present study, the composite films consisting of polypyrrole and SBA-15 was electrochemically prepared on an electrode suface. Multi-Potential Step electrodeposition technique was applied for preparation of Pt metal particles on the composite polypyrrole/SBA-15 support. The activity of Pt particles towards electro-oxidation of small organic molecules was investigated.Present studies provide a low cost and simply controlled test-bed for fundamental study on using ordered mesoporous films as new class of supports for catalysis.