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 m2/g) and a high pore volume (0.58−0.98 cm3/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 °C and collapsed at 1300 °C. The extremely high thermal stability of the PMTS is due to the high anatase−rutile transformation temperature (1300 °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.