Abstract
A modified solid state reduction (SSR) method, by which the platinum salt is reduced into platinum nanoparticles by sodium formate in solid state and under low temperature (below 180 °C) conditions, is introduced here. The high performance catalysts based on carbon nanotubes (CNTs) supported platinum and platinum promoted by Mo (VI) and Si (IV) was prepared successfully by this method. The catalysts, with small particle size and uniform distribution were active toward the electrooxidation reaction of methanol. Among a few catalysts promoted by silicon, molybdenum and tungsten elements, catalysts co-promoted by silicon and molybdenum elements show best performance. The particle size of promoted Pt/CNTs, calculated from XRD patterns, is small as 3.0±1.5 nm, and the results of transmission electron microscopy (TEM) revealed that the distribution of particle size is uniform. In comparison with the liquid-state synthesis, the advantages of SSR method include environmental benefits due to less water usage and significantly reduced pollutants generation, as well as suitability for large scale preparation.
Keywords: Solid state reduction, fuel cell catalysts, methanol electrooxidation, silicomolybdic acid