Kuzmich I. Phisico-chemical properties of Сu- and Сu, Рd-containing zeolite catalysts for CO oxidation

The physico-chemical properties of mono- (Сu-) and bimetalcontaining (Сu,Рd-) zeolites on the base of ZSM-5 and ERI with different metal quantity and their catalytic activity in CO oxidation have been investigated. According to DTA the activity of loaded zeolite catalysts with high content of Сu (10wt.%) depends on thermal precursor stability (Cu(CH3COO)2, Cu(NO3)2, [Cu(NH3)4]Cl2) and conditions of catalyst formation. It was found, that high disperse particles of active phase CuO are the active centres of 10%Сu-zeolites. The factors that determine the different activity of Cu-containing zeolites with low Сu content (1,8%Cu/ZSM-5, 3%Cu/ERI) were studied by ESR, ESDR, TPR-H2, IR-spectroscopy; these factors are the presence of distribution and localization of copper cations in the loaded systems, diifferent ability to CO adsorption. It was shown, that associates of coordinative-unsaturated Сu cations surrounded with extraframework oxygen atoms are characteristic for high active catalyst 1,8%Cu /ZSM-5. Higher catalytic activity of bimetal-containing Сu,Рd-systems is caused with formation of additional Сu-Рd-associates. Kinetics reguliarities and mechanism of carbon monoxide oxidation on catalysts Сu/ZSM-5 and Сu-Pd/ZSM-5 were studied, a kinetic equation was proved and it was shown, that the experimental data agree with Eley–Rideal mechanism.