One-pot synthesis of Pt-nanoparticle-embedded mesoporous titania/silica and its remarkable thermal stability

Abstract

Pt-nanoparticle-embedded mesoporous titania/silica (PMTS) was successfully synthesized in a one-pot process using tetraammineplatinum(II) hydroxide (TPH) precursor as a pore-forming agent, without any other templating agents. In the current report, we demonstrate the possibility of using the Pt precursor as a pore-forming agent. Using the TPH precursor as a pore-forming agent, we simultaneously achieved both mesostructure control of the PMTS and infiltration of Pt nanoparticles into the mesopores. The PMTS showed a high surface area (670-370 m(2)/g) and a high pore volume (0.58-0.98 cm(3)/g). The pore diameter of the PMTS was easily controlled from 4.8 to 10 nm with a sharp pore size distribution by simply changing the TPH concentration. Moreover, the mesostructure of the PMTS was stable up to 1000 degrees C and collapsed at 1300 degrees C. The extremely high thermal stability of the PMTS is due to the high anatase-rutile transformation temperature (1300 degrees C), which is attributed to nanocomposite formation between titania nanocrystals and thermally stable silica nanospheres. That is, silica nanospheres inhibited the coordination of the primary anatase clusters for rutile nucleation.