Structured monolithic catalyst for reducing nox emission in flue gas, the preparation method and the use thereof

A method for preparing a structured monolithic catalyst for reducing NOx emission in flue gas, comprising:

• in the first scheme:
• (1) making a slurry by mixing a source of a substrate, a precursor of a first metal element, a precursor of a second metal element, a precursor of a third metal element, a precursor of a fourth metal element, and water, to obtain a coating slurry of active components, and
• (2) coating a structured monolithic carrier with the coating slurry of active components, and then subjected to drying and the first calcining, to obtain the coating of active components disposed on inner surface and/or outer surface of the structured monolithic carrier, or
• in the second scheme
• a) making a slurry by mixing a source of a substrate, a precursor of a first metal element, a precursor of a second metal element, a precursor of a third metal element, and water, to obtain a first slurry,
• b) coating a structured monolithic carrier with the first slurry, and then subjected to drying and the second calcining, to form a coating comprising parts of active components on inner surface and/or outer surface of the structured monolithic carrier, to obtain a semi-finished catalyst, and
• c) coating the semi-finished catalyst obtained in the step b) with a solution comprising a precursor of a fourth metal element, and then subjected to drying and/or the third calcining, to obtain the coating of active components disposed on inner surface and/or outer surface of the structured monolithic carrier,
• wherein the first metal element is selected from the group consisting of the non-noble metal elements of the Group VIII, wherein the first metal element includes Fe and Co, wherein the second metal element is at least one selected from the group consisting of the metal elements of the Group IA and/or IIA, wherein the third metal element is at least one selected from the group consisting of the non-noble metal elements of the Groups IB to VIIB, and wherein the fourth metal element is at least one selected from the group consisting of the noble metal elements, and
• wherein the precursor of the first metal element comprises precursor of Fe and precursor of Co in an amount so that the obtained catalyst comprises, on an oxide basis, Fe and Co in a weight ratio of 1:(0.05-20)