The results are reported of an investigation into the influence of preparative conditions on catalyst performance, using silica-supported nickel as a model system. Nickel(Il)dimethylglyoximate was precipitated from aqueous solution in the presence of silica in a stirred mixing vessel. After filtration, washing and drying, reduction with hydrogen produced a catalyst of metallic nickel supported on silica. Catalysts thus prepared were characterised according to nickel crystallite size, specific metal surface area, reducibility, and specific catalytic activity. Varying the precipitation conditions enabled the relationship between preparative parameters and catalytic performance to be examined. The crystal size distribution of the Nickel(Il)dimethylglyoximate catalyst precursor was dependent upon a variety of precipitation parameters, but the properties and performance of the final catalyst were found to be independent of the preparation conditions. The reduction of nickel(H)dimethylgloximate by heating in hydrogen is accompanied by a sublimation process. This vapour-phase redistribution of the material prior to reduction is believed to be responsible both for the exceptionally high surface areas (>200m 2 /gNi) observed for catalysts prepared by this route, and for the discovered lack of correlation between catalytic activity and preparation conditions.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:633086 |
| Date | January 1990 |
| Creators | Elliott, Paul |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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