Catalytic features of Pt,Co-mordenite for the SCR of NOx monitored by DRIFT spectroscopy using adsorbed N2 as a probe

M. A. ULLA; L. GUTIERREZ; E. A. LOMBARDO; F. LÓNYI; J. VALYON

APPLIED CATALYSIS A-GENERAL

Elsevier

Año: 2004 vol. 277 p. 227 - 237

0926-860X

The location of cobalt and its interaction with platinum in Pt,Co-mordenite were studied using TPR, TPD, and N2 adsorption at varying pressures. The catalytic performance for the selective catalytic reduction (SCR) of NOx with CH4 was evaluated using a fixed –bed flow reactor. The effect of reducing, oxidizing, inert atmospheres, upon the location of the extra-framework cations was also investigated. The bimetallic Pt,Co-mordenite catalyst showed better N2 selectivity than the Co-mordenite. The TPR results indicated that more than 90% of cobalt waslocated at hard-to-reduce ion exchange positions. The high-pressure DRIFTS experiments, designed to give information about the adsorbed N2 indicated that both [Co(OH)]+ and Co2+ species were located in the main channels of the mordenite, while the residual Na+ and H+ were evenly distributed between the cation sites in the main channels and the side pockets. The small proportions of Pto and Coo formed after reduction at 350C were in intimate contact and promoted the conversion of NO to NO2, which is a better oxidant for methane than O2.