Silica gel modified due to pyrolysis of acetylacetone and metal (Ti, Cr, Co, Ni, Zn, Zr) acetylacetonates

Mesoporous silica gels modified due to pyrolysis of acetylacetone or acetyl acetonates (AcAc) of zirconium [Zr(AcAc)(4)], titanium [titanyl TiO(AcAc)(2 )], nickel [Ni(AcAc)(2)], zinc [Zn(AcAc)(2)], chromium [Cr(AcAc)(3)], and c obalt [Co(AcAc)(2)] were studied using nitrogen adsorption-desorption, TPD- DTG, TEM, XRD, and XRF methods. Grafted C/X phases consist of metal compoun ds (X denotes oxide, silicate, or metal crystallites) and pregraphite pyroc arbon, whose characteristics can be varied by changing the metal in M(AcAc) (n). The structural parameters of C/X/SiO2, such as the specific surface ar ea of micro- and mesopores, pore volume, pore size and fractal dimension di stributions, and adsorptive ability, depend nonlinearly on the concentratio ns of the C/X deposit due to alterations in the topology of grafted matters with increased concentrations and a possible catalytic effect of the X pha se on pyrolysis. (C) 2000 Academic Press.