NO adsorption on the active sites of Co- and/or in-containing ferrierite catalysts for the CH4-SCR-NO process

Catalytic tests, performed on Co-, In- and In/Co-ferrierites, revealed that those catalysts were efficient for the selective catalytic reduction of NO with methane (CH4-SCR) in the presence of water. Previous investigations have shown that a synergetic effect was present for the binary samples (In/Co-FER) of various exchange degrees—the conversion of NO to N2 was as high as 80–100% in a wide temperature range (520–820 K). NO sorption on In-, Co- and In/Co-ferrierites was followed by IR spectroscopy to identify nitrogen-containing species formed upon adsorption. We suggest that the synergetic effect could be due to the concurrent action of both kind of active species present in the binary catalysts: NO, adsorbed on Co2+ as mono- and dinitrosyls species could be easily transformed into nitro-oxygen compounds of higher ionic character on indium-oxygen compounds, which were introduced to the catalysts during the contact-induced ion exchange with In2O3 oxide.