Method of preparing a catalyst
AssigneeUnited Kingdom Atomic Energy Authority
InventorsJames A. Cairns, James L. Woodhead, John D. F. Ramsay
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Abstract
A catalyst suitable for use in the treatment of motor vehicle exhaust emissions is made by contacting a substrate, preferably of an aluminium bearing ferritic alloy, with a first sol of refractory material followed by drying and firing, and preferably then contacting with a second sol of refractory material, which additionally contains a salt convertible to catalytic material, followed by drying and firing. The sols are obtained from refractory material, e.g., alumina, made by a vapor phase condensation method.
Claims17
A method of preparing a catalyst comprising a substrate carrying refractory material which method comprises the steps of
- (i) contacting a substrate with a dispersion comprising colloidal particles of refractory material in a liquid medium, which refractory material has been prepared by a vapour phase condensation method, and
- (ii) drying and firing to produce a coating of the refractory material on the substrate.
A method of preparing a catalyst comprising the steps of
- (i) dispersing alumina in the form of substantially spherical primary-particles, prepared by a vapour phase condensation method, in water to give a sol;
- (ii) contacting said sol with an aluminium-bearing ferritic alloy which carries an essentially alumina surface layer, formed by oxidation of the alloy,
- (iii) drying and firing,
- (iv) dispersing alumina in the form of substantially spherical primary-particles prepared by a vapour phase condensation method in water to give a sol and providing in solution in the water a water-soluble salt of a platinum group metal and a water-soluble carbonisable polymer,
- (v) contacting the product of step (iii) with the sol of step (iv),
- (vi) drying and firing to reduce the salt to a platinum group metal and thereby produce the final catalyst.
Dependencies are inferred from the claim text.