Abstract: A catalyst which consists essentially of a carrier of active alumina and, distributed upon the carrier, at least one catalytic metal selected from Pt, Pd, Rh and Ir and is produced by impregnating the carrier with an aqueous solution of thermally decomposable catalytic metal salt(s) and baking the impregnated carrier in 100% steam at 300.degree.-600.degree. C. The total amount of the catalytic metal(s) in the catalyst is 0.03-0.3 Wt%, and the amounts of Rh and Ir both are limited to 0-0.03 Wt%. The catalyst features a high conversion ability for hydrocarbons, good durability and a low activity on the conversion of SO.sub.2 to SO.sub.3 particularly when a combination of Pt and/or Pd, and either Rh or Ir is used as the catalytic metals.

Abstract: A catalyst is prepared by firstly impregnating a carrier with a solution of a catalytically active metal compound and a sulfur compound and thereafter treating the impregnated carrier in a stream of high temperature steam.

Abstract: A catalytic alloy composed of 60-95% Ni, 2.5-20% Cu and 2.5-20% Co is electrodeposited on a carrier. The plating bath is an aqueous solution of the sulfates of the alloy component metals, containing a complexing agent such as Rochell salt to cause deposition potentials of the metals to fall in a common range.

Abstract: A refractory article is coated with a metal film by electroless plating. Particles of .gamma.-alumina are deposited on the surface of the coated article by electrodeposition to prepare a catalyst carrier.