In this study, a commercial chabazite, with low addition of copper phase (ca. 1.5-3 wt.%) deposited from Cu-acetate, Cu-nitrate, and Cu-chloride precursors (Cu/CHA) by ionic-exchange and impregnation procedures, was investigated in NH3-SCR and in NH3-SCO reactions, in the 120-500°C range. The study is aimed at discovering the possibility to couple the two processes to realize complete NOx abatements working with high NH3/NOx ratio, without any NH3 release. Differences of Cu sitting on external and internal surface of CHA were evidenced by Uv-DRS, EPR, and H2-TPR analyses. The presence of well dispersed Cu2+ centers, acting as Lewis acid sites, increased the acidity of bare chabazite. Aggregated CuOx domains were also formed when the Cu-phase was deposited by impregnation procedure. All the Cu/CHA samples were active and selective in NH3-SCR reaction with differences in the temperature of maximum activity. NH3-SCO selectivity to N2 was higher on the samples with better Cu-dispersion.
Study of copper-chabazites for NH3-SCR and NH3-SCO cascade process / S. Campisi, M. Schiavoni, A. Gervasini. ((Intervento presentato al 13. convegno European Congress on Catalysis tenutosi a Firenze nel 2017.
Study of copper-chabazites for NH3-SCR and NH3-SCO cascade process
S. Campisi
;M. Schiavoni;A. Gervasini
2017
Abstract
In this study, a commercial chabazite, with low addition of copper phase (ca. 1.5-3 wt.%) deposited from Cu-acetate, Cu-nitrate, and Cu-chloride precursors (Cu/CHA) by ionic-exchange and impregnation procedures, was investigated in NH3-SCR and in NH3-SCO reactions, in the 120-500°C range. The study is aimed at discovering the possibility to couple the two processes to realize complete NOx abatements working with high NH3/NOx ratio, without any NH3 release. Differences of Cu sitting on external and internal surface of CHA were evidenced by Uv-DRS, EPR, and H2-TPR analyses. The presence of well dispersed Cu2+ centers, acting as Lewis acid sites, increased the acidity of bare chabazite. Aggregated CuOx domains were also formed when the Cu-phase was deposited by impregnation procedure. All the Cu/CHA samples were active and selective in NH3-SCR reaction with differences in the temperature of maximum activity. NH3-SCO selectivity to N2 was higher on the samples with better Cu-dispersion.File | Dimensione | Formato | |
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