Spectroscopic study of tetradecyltrimethylammonium bromide Pt-C14TAB nanoparticles: structure and stability.

The vibrational spectra of platinum nanoparticles (12 nm) capped with tetradecyltrimethylammonium bromide, C(14)TAB, were investigated by Fourier transform infrared (FTIR) spectroscopy. We have shown that the thermal decay of Pt-C(14)TAB nanoparticles in N(2), H(2), and O(2) atmospheres leads to the release of the hydrocarbon chain of the surfactant and the formation of a strongly bonded layer of ammonium cations on the platinum surface. The platinum atoms accessible to CO chemisorption were not reducible by hydrogen in the temperature range from 30 to 200 degrees C.

Probing the interaction of poly(vinylpyrrolidone) with platinum nanocrystals by UV-Raman and FTIR.

The vibrational spectra of platinum nanoparticles (2.4-9 nm) capped with poly(N-vinylpyrrolidone) (PVP) were investigated by deep UV-Raman and FTIR spectroscopy and compared with those of pure PVP. Raman spectra of PVP/Pt show selective enhancement of C=O, C-N, and CH2 vibrational modes attributed to the pyrrolidone ring.

Structure sensitivity of vibrational spectra of mesoporous silica SBA-15 and Pt/SBA-15.

The vibrational properties of mesoporous silica (SBA-15) were investigated by deep ultraviolet (UV) Raman and infrared spectroscopies with and without the presence of platinum nanoparticles in the mesopores that were incorporated by sonication. Raman and IR spectral line assignments were made by comparison to amorphous silicas. This procedure permitted identification of vibrations of longitudinal (LO) and transverse (TO) optical lattice modes, the presence of Si-OH, and vibrational modes associated with the presence of three-, four-, and six-membered siloxane rings.