IN SITU FTIR STUDY OF THE THERMAL TREATMENT ON BORON CONTAINING MESOPOROUS MOLECULAR SIEVE MCM-41

摘要

In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to study the calcination of as-synthesized boron-containing MCM-41 mesoporous molecular sieves in air, nitrogen, and vacuum up to 550 ℃. The FTIR spectra show that the organic molecules on the surface of the molecular sieves are thermally much more stable than the ones inside the molecular sieves. Unlike the protonic form of MCM-41, the vibrations of isolated terminal silanol groups (at 3746 cm-1) and bridging hydroxy groups(Si-OH-B groups, at 3700 cm-1) only emerge during calcination. The FTIR study also reveals that the mechanism of the surfactant template thermal decomposition depends on the atmosphere.