Journal of Colloid and Interface Science, Vol.231, No.1, 13-25, 2000
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 acetylacetonates (AcAc) of zirconium [Zr(AcAc)(4)], titanium [titanyl TiO(AcAc)(2)], nickel [Ni(AcAc)(2)], zinc [Zn(AcAc)(2)], chromium [Cr(AcAc)(3)], and cobalt [Co(AcAc)(2)] were studied using nitrogen adsorption-desorption, TPD-DTG, TEM, XRD, and XRF methods. Grafted C/X phases consist of metal compounds (X denotes oxide, silicate, or metal crystallites) and pregraphite pyrocarbon, 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 area of micro- and mesopores, pore volume, pore size and fractal dimension distributions, and adsorptive ability, depend nonlinearly on the concentrations 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 phase on pyrolysis.
Keywords:mesoporous silica gel;metal (Ti;Cr;Co;Ni;Zn;Zr) acetylacetonate pyrolysis;carbon deposit;carbon-metal compound deposit;pore size distribution;fractal dimension distribution;TEM;TPD-DTG;water desorption;activation energy distribution