Characterization of silica catalyst supports by single and multiple quantum proton NMR spectroscopy
- Ames Lab., IA (United States)
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 in the presence and in the absence of ruthenium. Single quantum spin counting of protons on silica support with and without ruthenium metal indicated that the total number of hydroxyl groups decreased significantly with increasing reduction temperature over the range of 350-530{degree}C. Two different components shown in static {sup 1}H NMR were found to reveal homogeneous and inhomogenous broadening via spectral hole burning experiments. {sup 1}H MQ-NMR spin, counting, based on the number of MQ coherences observed, showed the existence of small clusters of proton spins on the silica surface. The maximum measured cluster size was 6-7, or less, spins. Segments of silica resembling the 100 face of cristobalite on the surface are postulated to be possible sites for the clusters. The clusters in pure silica became smaller as the reduction temperature increased over 500{degree}C. No such change was detected in the presence of ruthenium. 33 refs., 11 figs., 2 tabs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 35468
- Journal Information:
- Journal of Physical Chemistry, Vol. 99, Issue 11; Other Information: PBD: 16 Mar 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of silica support on Ru-Cu cluster morphology as determined by catalytic activity
The effect of chlorine on hydrogen chemisorption by silica-supported Ru catalysts: A proton NMR study