Effect of Carbon Deposits on the Structure of Hybrid C/TiO₂/SiO₂ Adsorbents

Abstract

ABSTRACT:The structural characteristics of pyrocarbon/X (X = fumed silica, mesoporous silica gel, fumed titania/silica, CVD-TiO 2 /fumed silica, CVD-TiO 2 / silica gel) prepared using several precursors [CH 2 Cl 2 , cyclohexene and TiO(AcAc) 2 , where Ac = acetylacetonate] were studied using the nitrogen adsorption/desorption method and an improved technique to allow the calculation of pore size distributions applying regularization procedures. Various pore models were used for the carbon phase. The pyrocarbon structure and distribution on the TiO 2 /SiO 2 supports depends primarily on the structural features of the titania phase which exhibits catalytic activity in the pyrolysis of organic materials. The formation of relatively large concentrations of pyrocarbon typically reduces the porosity and specific surface area of the hybrid adsorbents produced.

Advanced Analysis of SEM Images of Carbon-Ceramic Composites

“…This process has long been studied in the context of the poisoning of catalysts by coke formation on their surfaces (Bruckner et al 1999;Eberly et al 1966;Pasieczna et al 2004). More recently, carbon-ceramic composites were proposed as new functional materials which combine the features of their components (Gunko et al 2000;Kosmulski et al 2007;Leboda et al 2001). Ultimately, the carbon deposits can be separated from the catalysts' surfaces and used as a separate product, e.g.…”

“…in the form of nanotubes (Lysenkov et al 2007;Piedigrosso et al 2000). Physical methods which have been used to study such carbon deposits include thermogravimetric analysis (Gunko et al 2000;Kosmulski et al 2007;Leboda et al 2001), low-temperature nitrogen adsorption (Gunko et al 2000;Kosmulski et al 2007;Leboda et al 2001) and IR spectroscopy (Eberly et al 1966;Pasieczna et al 2004). The results obtained by means of these methods can be easily quantified.…”