CATALYST FOR NEUTRALIZING EXHAUST GASES FROM DIESEL ENGINES AND A METHOD FOR PREPARATION THEREOF Russian patent published in 2005 - IPC

FIELD: exhaust gas neutralization catalysts.

SUBSTANCE: catalyst contains at least one zeolite and additionally at least one oxide carrier selected from alumina, silica, titanium dioxide, and aluminum silicate, and also at least one precious metal selected from platinum, palladium, rhodium, and iridium. The latter are characterized by average oxidation degree below +2.5, average number of metal ligands more than 3, and average number of oxygen ligands less than 3, whereas precious metal atoms are present on zeolites and oxide carriers in the form of crystallites with average particle size 1-6 nm. Catalyst is prepared on an solid cellular element, for which oxide carriers and zeolites are first separately impregnated with precious metal precursors and then calcined in yet wet state by blowing them into gaseous combustion gases at 500-1000°C for 0.1 to 10 sec. Thereafter, common coating dispersion is processed, which is further used to coat solid cellular element. Coating is then dried, calcined, and reduced.

EFFECT: increased catalytic activity, prolonged lifetime of catalyst, and lowered minimum working temperature at which carbon monoxide and hydrocarbons start being catalytically converted.

10 cl, 8 tbl, 11 ex