Catalysts for the selective catalytic reduction of NOx by ammonia are made from porous formed supports having a certain fraction of the pores with pore diameters larger than 600 Angstrom units. Thus macropores can be introduced in a formed TiO₂ support by adding burnout materials or some inorganic oxide prior to forming the titania into the formed support. Alternatively, titania is precipitated onto a porous inorganic oxide such as SiO₂, Al₂O₃, ZrO₂, AlPO₄, Fe₂O₃ and B₂O₃ to form the support. Then conventional DeNOx catalytic metals are added. The support can be made by first impregnating the inorganic oxide particles with titania via a soluble precursor, forming titania and then shaping the coated particles into the desired shape such as a monolith. In a second embodiment, the inorganic oxide particles are first formed into the desired shape and then impregnated with the titania forming material. Barium sulfate can be added to the surface of the porous inorganic oxide to make an improved support.

Catalysts for selective catalytic reduction denox technology

Verfahren und vorrichtung zur selektiven katalytischen no(pfeil abwaerts)x(pfeil abwaerts)-reduktion in sauerstoffhaltigen abgasen

A process for preparing shaped catalysts or carriers mainly containing titanium oxide and improved in mechanical strength which comprises calcining a material mainly comprising titanium oxide or a substance convertible into titanium oxide on calcination in the presence of metatitanic acid sol or gel, said metatitanic acid sol being the one prepared by deflocculation of metatitanic acid obtained in the course of the production of titanium oxide according to a conventional sulfuric acid process and said metatitanic acid gel being the one prepared by adjusting said metatitanic acid sol to pH 1 or higher.

Production of shaped catalysts or carriers comprising titanium oxides

A nanocomposite particle, its use as a catalyst, and a method of making it are disclosed. The nanocomposite particle comprises titanium dioxide nanoparticles, metal oxide nanoparticles, and a surface stabilizer. The metal oxide nanoparticles are formed hydrothermally in the presence of the titanium dioxide nanoparticles. The nanocomposite particle is an effective catalyst support, particularly for DeNOx catalyst applications.

Nanocomposite particle and process of preparing the same

A denitration catalyst comprising at least three metal components, (A) titanium, (B) tungsten and/or magnesium, and (C) vanadium, the titanium and tungsten being contained as oxides and the magnesium and vanadium being contained in the form of an oxide or a sulfate or both, said catalyst being composed of a porous molded article of a mixture of an oxide of component A and an oxide and/or a sulfate of component B, the atomic ratio of component B to component A being from 0.01 to 1, and a vanadium compound localized in that area of said molded article which extends from its outermost surface to a depth of 500 microns or less, the content of the vanadium compound in said area being 0.1 to 15% by weight; and a method for removing nitrogen oxides from a waste gas, which comprises contacting a waste gas containing nitrogen oxides, together with ammonia and molecular oxygen, at a temperature of 150° to 650° C., with the aforesaid catalyst.

Denitration catalyst and denitrating method

A catalyst for the selective reduction of nitrogen oxides in exhaust gases in the presence of ammonia is vanadium oxide supported on a specific carrier of the anatase form of titanium oxide

Shinichi Fujii

Papers

Catalyst for selective reduction of nitrogen oxides

Verfahren zur zersetzung von stickstoffoxyden