Characterization of Silica Catalyst Supports by Single and Multiple Quantum Proton NMR Spectroscopy

摘要: Cab-O-Sil HS5, used as the support in silica supported ruthenium (Ru/SiO{sub 2}) catalysts, was characterized via single and multiple quantum (MQ) {sup 1}H NMR spectroscopy. The samples were studied both presence absence of ruthenium. Single spin counting protons on with without metal indicated that total number hydroxyl groups decreased significantly increasing reduction temperature over range 350-530{degree}C. Two different components shown static found to reveal homogeneous inhomogenous broadening spectral hole burning experiments. MQ-NMR spin, counting, based MQ coherences observed, showed existence small clusters proton spins surface. maximum measured cluster size 6-7, or less, spins. Segments resembling 100 face cristobalite surface are postulated be possible sites for clusters. pure became smaller increased 500{degree}C. No such change detected 33 refs., 11 figs., 2 tabs.