Abstract: A catalyst structure comprises a shape retaining metal core of the desired shape, a particle holding layer attached to the core and made of a glass fiber product and catalyst particles held in the layer.

Abstract: A plate-shaped denitrating catalyst comprising a metal net, a finely divided porous carrier retained on the metal net with a binder and covering the metal net, and an active component supported on the carrier.

Abstract: A plate-shaped denitrating catalyst is produced by the steps of preparing a slurry from hydrated titania and a sol selected from the group consisting of silica sol, alumina sol and titania sol, firing the slurry to obtain a porous material, pulverizing the porous material to a powder, causing a metal net to support the powder thereon with a binder to form a plate-like piece, drying or firing the piece to obtain a porous carrier and depositing a catalytically active component on the carrier.

Abstract: A highly active denitrating catalyst is produced by converting the surface layer of steel material to an aluminum alloy, treating the resulting steel material with an aluminum dissolving solution to dissolve out the aluminum and to render the surface layer porous, and immersing the steel material having the porous surface layer in a solution containing a vanadium compound to cause the porous surface layer to support the vanadium compound.

Abstract: A catalyst for decomposing ammonia by oxidation is produced by converting the surface layer of steel material of specified shape resembling a ring, honeycomb, plate or the like to an aluminum alloy, treating the steel material with an aluminum dissolving solution to dissolve out the aluminum and to render the surface layer porous, subjecting the steel material to oxidation treatment to obtain a catalyst carrier, and causing the carrier to support platinum.

Abstract: A denitrating catalyst having a porous coating is produced by immersing a catalyst base of porous metal in a silica-containing coating bath, drying the catalyst base to form a carrier having a porour silica coating, immersing the carrier in a solution containing an active component and drying the resulting carrier to cause the carrier to support the active component thereon.

Abstract: An oxidizing metal catalyst incorporating platinum is produced by converting the surface layer of steel material of specified shape resembling a ring, honeycomb, plate or the like to an aluminum alloy, treating the steel material with an aluminum dissolving solution to dissolve out the aluminum and to render the surface layer porous, subjecting the steel material to oxidation treatment to obtain a catalyst carrier, immersing the carrier in a solution of chloroplatinic acid adjusted to weak alkalinity with sodium hydroxide, and drying the carrier after withdrawing the carrier from the solution.

Abstract: A catalyst for decomposing ammonia by oxidation is produced by converting the surface layer of steel material of specified shape resembling a ring, honeycomb, plate or the like to an aluminum alloy, treating the steel material with an aluminum dissolving solution to dissolve out the aluminum and to render the surface layer porous, subjecting the steel material to oxidation treatment to obtain a catalyst carrier, immersing the carrier in a solution of chloroplatinic acid adjusted to weak alkalinity with barium hydroxide, and drying the carrier after withdrawing the carrier from the solution.

Abstract: In a boiler having a plurality of heat exchanger stages such as a superheater, an evaporator and a preheater, disposed in a combustion gas channel between heat exchangers including an optimum catalytic reaction temperature region are a denitration catalyst layer crossing said channel and a reductant feeding device for adding a reductant such as ammonia gas at a point a little short of catalyst layer. The denitration catalyst layer comprises a number of plate-like catalyst bodies whose plate surfaces extend along the direction of flow of gas, and desirably it is honey-comb-shaped. If the boiler is a waste heat boiler, the denitration catalyst layer will be disposed between the superheater and the evaporator.

Abstract: Nitrogen oxides are removable from an exhaust gas containing a reductant such as carbon monoxide, hydrogen and methane by contacting the gas with a catalyst composed of alumina, copper, rhodium or ruthenium, and at least one of the alkali metals, the alkaline earth metals and the transition metals; for example, a catalyst composed of 0.051%Rh--5%Cu--3%Mg--Al.sub.2 O.sub.3. The activity of such catalysts is not influenced by the presence of O.sub.2, H.sub.2 O and SO.sub.2 in the exhaust gas.

Abstract: A denitrating catalyst is produced by plating the surface of unactivated metal with aluminum and immersing the resulting layered product in an aqueous aluminum-dissolving solution to dissolve out the aluminum into the aqueous solution and to thereby activate the surface of the metal.

Abstract: Nitrogen oxides in an exhaust gas are selectively removable by employing ammonia as a reductant and by employing a catalyst composed of alumina, copper, and at least one of the alkali metals, the alkaline earth metals and the transition metals. Optionally, the catalyst composition may include a slight amount (less than 1% by weight) of a precious metal such as rhodium, ruthenium, plantinum and palladium. This selective removal of nitrogen oxides is not impaired by the presence of O.sub.2, H.sub.2 O and SO.sub.2 in the exhaust gas.

Abstract: Exhaust gas cleaning catalysts are produced by alloying copper and aluminum with at least one of the elements, nickel and chromium, and eluting by alkali or acid means aluminum from the cooled alloy surface. Small amounts of other metals from the fourth or fifth period V.about. VIII groups, may be added to the catalysts by alloying, or by impregnation, for enhanced catalytic properties. The catalysts exhibit improved reduction of NO and oxidation of CO in an exhaust gas stream, in the presence of Pb, SO.sub.2, moisture and hydrocarbons (H.C) and at relatively low temperatures.