Effects of Pressure, Thermal Treatment, and O2 Loading in MCM41, MSU-H, and MSU-F Mesoporous Silica Systems Probed by Raman Spectroscopy

Risultato della ricerca: Articlepeer review

3 Citazioni (Scopus)

Abstract

We present a Raman study of the effects induced by pressure, thermal treatments, and O2 loading in MCM41, MSU-H, and MSU-F representative mesoporous silica. We compared the starting powders with the mechanically pressed tablets produced applying pressures of ∼0.2 and ∼0.45 GPa. The spectra of the three untreated tablets evidence that the main value of the Si-O-Si angle decreases and that in the MCM41 and the MSU-H Si-O-Si hydrolysis occurs, whereas such a process is absent or much less efficient in the MSU-F. Despite their different networks, the three powders tend to crystallize in cristobalite when treatments are at 1000 °C. The MCM41 and MSU-H tablets exhibit behavior similar to their starting powders, whereas the MSU-F tablets tend to form the tridymite crystalline phase. Such a finding could be related by the differences in the Si-O-Si hydrolysis, occurring during the tablets production. Finally, we inserted O2 molecules within the interstices of the SiO2 wall only in MSU-F. By monitoring the O2 content as a function of the delay time from the loading end, we provide evidence that the O2 remains in the interstices for a sufficiently large time to modify the material properties by inserting small molecules and not only through the surface functionalization.
Lingua originaleEnglish
pagine (da-a)27434-27441
Numero di pagine8
RivistaJOURNAL OF PHYSICAL CHEMISTRY. C
Volume119
Stato di pubblicazionePublished - 2015

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • ???subjectarea.asjc.2100.2100???
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Fingerprint Entra nei temi di ricerca di 'Effects of Pressure, Thermal Treatment, and O2 Loading in MCM41, MSU-H, and MSU-F Mesoporous Silica Systems Probed by Raman Spectroscopy'. Insieme formano una fingerprint unica.

Cita questo