화학공학소재연구정보센터
Journal of Molecular Catalysis A-Chemical, Vol.156, No.1-2, 195-203, 2000
Controlled deposition of chromium hexacarbonyl on silica surfaces in a fluidised bed reactor
Cr(CO)(6)/silica samples were prepared in a fluidised bed reactor by vapor phase adsorption of zerovalent chromium hexacarbonyl under N-2 flow. Two different preparation methods were used; a vaporisation method without decarbonylation step and a pulse method in which a sample was decarbonylated after vaporisation, followed by repeated vaporisation-decarbonylation cycles. The chromium content can be controlled and weakly adsorbed chromium species can also be removed from the silica surface using the pulse method. The chromium carbonyl/silica interactions were characterised using diffuse reflectance Fourier transform IR spectroscopy (DRIFT). Si-29 cross-polarisation magic-angle spinning (CP MAS) NMR studies indicated that chromium hexacarbonyl interacts with single silanols of the silica surface even though the interaction is either physisorption or weak chemisorption. Samples were also characterised by temperature programmed techniques. The preoxidation temperature influences to the reduction of the samples.