PLATINUM GROUP METAL AND BASE METAL ON MOLECULAR SIEVE FOR SYSTEMS WITH TIGHTLY CONNECTED PASSIVE NO ADSORBER, CATALYST FOR PREVENTING AMMONIA SLIP AND CATALYST FOR SELECTIVE CATALYTIC REDUCTION Russian patent published in 2021 - IPC B01D53/94 B01J20/18 B01J21/08 B01J23/40 B01J23/70 

FIELD: chemical industry; environmental protection.

SUBSTANCE: catalytic product contains substrate having input and output ends, the first and the second zones. The first zone contains a passive NOx adsorber (hereinafter – PNA), in which platinum group metal and base metal are located on a molecular sieve, and an ammonia slip-preventing catalyst (ASC) consisting of an oxidation catalyst, in which platinum group metal is located on a carrier, and the first selective catalytic reduction (hereinafter – SCR) catalyst, at a mass ratio of the first SCR catalyst to platinum group metal on the carrier from 10:1 to 50:1. A mixture of the oxidation catalyst and the first SCR catalyst is located in a lower later, and in an upper layer, the second SCR catalyst is located. The second zone contains a catalyst selected from a diesel oxidation catalyst (DOC) and a diesel exothermal catalyst (DEC). The first zone is located upstream of the second zone. The carrier contains silicon-containing material selected from silicon dioxide and zeolite with a molar ratio of silicon dioxide to aluminum oxide exceeding 200. Platinum group metal of the oxidation catalyst contains platinum, palladium or a combination thereof. The first and the second SCR catalysts, as well as PNA contain copper, iron, manganese, palladium or combinations thereof. A mass ratio of the first SCR catalyst and PNA is from 5:1 to 1:5. The lower layer may additionally contain a section with PNA located upstream of the mixture that also may additionally contain PNA. The lower layer may also contain a section with PNA and the third SCR catalyst. The first and the second zones may be located on the same substrate, wherein the first zone is located on its input side, and the second zone is located on its output side. Substrate may also consist of the first and the second substrates, while the first zone is located on the first substrate, and the second zone is located on the second substrate. To reduce emissions of harmful substances, an exhaust gas flow is subjected to a contact with the specified catalytic product. When a temperature of this flow does not exceed 180°C, a ratio of ammonia : NOx is not less than 1, and when its temperature is 180°C or more, this ratio exceeds 0.5.

EFFECT: invention provides for the reduction in NOx content during a cold start.

25 cl, 47 dwg