Abstract: The invention provides a catalyst for catalytic reduction of nitrogen oxides which uses a hydrocarbon or an oxygen-containing organic compound as a reducing agent, which comprises silver aluminate supported on a solid acid carrier material. The invention also provides a catalyst which comprises silver aluminate and at least one transition element selected from the group consisting of W, Mo and V, each supported on a solid acid carrier material. The invention further provides a method for producing such catalysts and a method for catalytic reduction of nitrogen oxides by use of such catalysts as above mentioned.

Abstract: A process for removing nitrogen oxide from exhaust is disclosed, comprising contacting exhaust containing nitrogen oxide with an alumina catalyst which contains not more than 0.5% by weight of an alkali metal and/or an alkaline earth metal and has a total pore volume of from 0.48 to 1.2 cm.sup.3 .multidot.g.sup.-1 with 0.26 to 0.6 cm.sup.3 .multidot.g.sup.-1 of the total pore volume being formed of pores of not greater than 80 .ANG. or has a volume of pores formed of pores of not greater than 60 .ANG. of from 0.06 to 0.2 cm.sup.3 .multidot.g.sup.-l and which may have supported thereon tin in an oxidative atmosphere containing excess oxygen in the presence of a hydrocarbon or an oxygen-containing organic compound.

Abstract: A catalyst for catalytic reduction of nitrogen oxides using a hydrocarbon and/or a oxygen-containing organic compound as a reducing agent is disclosed, which comprises a cerium oxide supported on a solid acid carrier.Also, a catalyst for catalytic reduction of nitrogen oxides using a hydrocarbon and/or an oxygen-containing organic compound as a reducing agent is disclosed, which comprises:(a) at least one element selected from the elements of Group Ib, Group IIa, Group IIb, Group IIIa, Group IIIb, Group IVa, Group IVb, Group Va, Group VIa, Group VIIa, and Group VIII in the Periodic Table (hereinafter referred to as the elements belonging to group (a)); and(b) a cerium oxide, supported on a solid acid carrier.

Abstract: A novel catalyst for catalytic reduction of nitrogen oxide using a hydrocarbon as a reducing agent is provided, which comprises (a) at least an element of the platinum group selected from the group consisting of platinum, iridium, rhodium and ruthenium and (b) gold, and which may further comprises (c) at least a metallic oxide selected from the group consisting of cerium oxide, lanthanum oxide, neodymium oxide, germanium oxide and gallium oxide.

Abstract: A catalyst for catalytic reduction of nitrogen oxide using at least one reducing agent selected from the group consisting of a hydrocarbon and an oxygen-containing organic compound is described, which includes an oxide represented by formula (V):A.sup.5.sub.x B.sup.3.sub.3-x C.sup.4.sub.3 O.sub.7 (V)wherein A.sup.5 represents at least one element selected from the group consisting of La, Y, Ce, Pr, Nd, Sm, Eu, and Gd; B.sup.3 represents at least one element selected from the group consisting of Ba, Sr, Ca, Mg, Pb, Zn, and Ag; C.sup.4 represents at least one element selected from the group consisting of Mn, Co, Fe, Ni, Cr, Cu, V, Mo, W, Ti, Zr, Nb, Pd, Rh, Ru, and Pt; and x is a number of from 0 to 1, supported on a solid acid carrier.