METHOD OF CATALYST PREPARATION AND CATALYST FOR EXHAUST GAS TREATMENT IN INTERNAL COMBUSTION ENGINES

摘要

FIELD: chemistry.;SUBSTANCE: invention concerns neutralisation catalysts for exhaust gas (EG) of internal combustion engines (ICE) and industrial effluent gas. Catalyst is obtained due to: 1) adding orthophosphoric acid to coating suspension to obtain alumophosphate, a binding substance, the total composition of which serves for coating reinforcement and thermal stabilisation of porous coating structure; 2) energy heterogeneity increase by adding zyrconyl dihydrophosphate to coating suspension, so that the total composition serves to enhance heat resistance of both modified aluminium oxide and catalytic contacts, i.e. of the whole catalyst. Invention claims method of catalyst preparation, involving preliminary processing of inert Al-containing foil block carrier by baking at 850-920°C in air flow for 12-15 hours, followed by carrier application onto intermediary modified aluminium oxide coating surface from suspension at room temperature, thermal processing of block with intermediary coating in air flow and further applying one or more active catalytic metals of platinum group. Intermediary coating is applied from suspension containing additionally orthophosphoric acid and zyrconyl dihydrophosphate at the following component ratio, wt %: aluminium hydroxide (pseudobemite) - 22-32, aluminium nitrite - 2-4, cerium nitrite - 2-5, orthophosphoric acid - 1-2, zyrconyl dihydrophosphate - 1-3, water - up to 100; thermal processing of block with intermediary coating is performed at 620-650°C with maturing for 1.8-2 hours. Invention also claims catalyst including metal block carrier, intermediary coating of modified aluminium oxide and active phase of noble metals of platinum group applied onto porous surface of intermediary coating. Catalyst includes 7-14 wt % of modified Al₂O₃ with specific surface area of 120-130 m²/g, which includes additionally aluminium phosphate and zyrconyl phosphate at the following weight ratio of coating components (%): aluminium oxide (89.7-71.4), cerium oxide - (3.5-9.7), aluminium phosphate - (3.6-8.1), zyrconyl dihydrophosphate - (3.2-10.9).;EFFECT: significant enhancement of mechanical and heat resistance of catalytic coating at high efficiency in waste gas treatment process, prolonged lifetime.;2 cl, 2 tbl, 26 ex