INFLUENCE OF BINDER AND SULFATE-IONS ON THE DISTRIBUTION AND PROPERTIES OF ACTIVE-SITES FOR COMPLETE OXIDATION OF ALKANES ON COMPOSITE CATALYSTS BASED ON HZSM-5 ZEOLITE

The peculiarities of the stabilization of Cu2+ and Cr5+ ions in the [H ZSM-5 + Al2O3] system and the catalytic properties of these composite materials in the complete oxidation of CH4 are studied. The specific a ctivity of isolated cations stabilized in the channels of HZSM-5 zeoli te is shown to substantially exceed that of the ions at the surface of Al2O3. The Al2O3 phase in the composite catalysts is responsible for the strong interaction with a considerable part of the active componen t and, thereby, for the lower activity of the composite systems relate d to 1 g of the active phase. Silicon dioxide used as a binder does no t influence the formation of the most active centers for CH4 oxidation and N2O decomposition on zeolites. Sulfate ions are capable of strong interaction with HZSM-5 by changing the topology of the most active c oordinately unsaturated cations, thus decreasing the specific activity of the systems.