Study on adsorption of NOx over CoH-FBZ by temperature-programmed desorption technique

Selective catalytic reduction of NO by methane in the presence of excess oxygen over CoH-FBZ zeolite composite catalyst has an advantage over the physical mixture of CoH-Y and CoH-Beta. The interaction between NO or NO+O2 and the catalyst revealed by adsorption and temperature-programmed desorption (TPD) technique, results directly in the effect of the topological structure of supports upon the stability of N- and O- species on the surface of the catalysts. The NO+O2-TPD profile of the CoH-FBZ catalyst exhibits two NO2 desorption peaks at 630 K and 660 K, respectively. This indicates that new adsorption centers for –NOy are formed over the CoH-FBZ and adsorbed more stably on CoH-FBZ than on CoH-Y or CoH-Beta. The synergism of the newly formed Co sites and the new strong acidic sites contributes to the novel CH4-SCR catalytic properties of the CoH-FBZ catalysts.