Vv. Turov et al., STUDY OF HYDRATED STRUCTURES ON THE SURFACE OF MESOPOROUS SILICAS ANDCARBOSILS BY H-1-NMR SPECTROSCOPY OF ADSORBED WATER, Langmuir, 13(5), 1997, pp. 1237-1244
H-1 NMR spectroscopy of adsorbed water was used to study mesoporous si
lica gel and carbosils synthesized with carbon in the range from 4 to
14.5% w/w in the surface layer. It has been revealed that both silica
gel and carbosil are characterized by a rise in temperature of water f
reezing in an aqueous medium in mesopores. This phenomenon may be expl
ained by contact of water adsorbed in pores with a continuous aqueous
medium. The changes in free energy of water in pores due to adsorption
have been calculated. It has been shown that carbonization of the mes
opore silica gel surface leads to formation of carbon layers which are
denser than those on a nonporous silica and the main types of water a
dsorption sites on the sui face are basic graphite planes of carbon an
d oxygen-containing groups on the carbon part of the carbosil surface.