Nano-structured Pt embedded in acidic salts of heteropolymolybdate matrices: MS EXAFS study

作者：Witkowska Agnieszka^*; Dsoke Sonia; Marassi Roberto; Di Cicco Andrea

来源：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms , 2015, 364: 65-69.

DOI：10.1016/j.nimb.2015.06.013

• Embedded metallic nanoparticles
• Structure
• EXAFS

A structural study of Pt nano-catalysts is presented in the paper. The innovation in the case of the considered catalytic materials resides in the use a meso-microporous inorganic matrix of heteropolyacid salt of composition X2.5H0.5YMo12O40 where X = Rb, Cs and Y = P, Si as a catalyst support. Metallic nanopartides were created by platinum ions reduction in a hot H-2/Argon stream and were mainly located into matrix pores. As the porous structure can be controlled by the type and content of the cation used, the desired/optimal Pt nanoparticle size can be precisely defined by using a proper heteropolyacid salt composition. Multiple-scattering extended X-ray absorption fine structure (MS EXAFS) analysis was applied to obtain the relation between the matrix composition and the size of the catalyst nanoparticles. The results showed that it was only the secondary structure form of the heteropolymolybdate salt (i.e. Rb or Cs cations) that influenced the metallic nanoparticle size. The smaller the X atom ionic radii, the larger the mean diameter of the embedded Pt nanoparticles.

• 出版日期2015-12-1