The effect of trivalent framework heteroatoms in Cu-CHA on the Selective Catalytic Reduction of NO
[Display omitted] •B- or Ga-substituted CHA zeolites were used as hosts for Cu2+ in deNOx SCR.•Activity of Cu-Ga-CHA is on par with that of the Al-analogue.•The stability of the Cu-Ga-CHA can be adjusted via the Si/Ga ratio.•Remarkably, N2O make by Cu-Ga-CHA is significantly lower than on Cu-Al-CHA....
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Published in | Applied catalysis. A, General Vol. 626; p. 118326 |
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Main Authors | , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier B.V
25.09.2021
Elsevier Science SA |
Subjects | |
Online Access | Get full text |
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Summary: | [Display omitted]
•B- or Ga-substituted CHA zeolites were used as hosts for Cu2+ in deNOx SCR.•Activity of Cu-Ga-CHA is on par with that of the Al-analogue.•The stability of the Cu-Ga-CHA can be adjusted via the Si/Ga ratio.•Remarkably, N2O make by Cu-Ga-CHA is significantly lower than on Cu-Al-CHA.
The effect of the trivalent framework atoms (Si4+/M3+ = 13-105) in Cu exchanged CHA-type zeolites was investigated for the selective catalytic reduction of NO with NH3. While the increased hydrophobicity of B-CHA compared to Al-CHA could make it a good candidate for low temperature SCR, the material was too unstable under reaction conditions and the exchanged Cu2+ did not remain isolated. Consequently a lower activity and selectivity than for Al-CHA were observed. Ga-CHA on the other hand showed a similar Cu2+ speciation as Al-CHA at similar Si4+/M3+ ratios. The difference in catalytic activity was remarkably small. While Ga-CHA was less stable upon hydrothermal aging, this was markedly improved by increasing the Si/Ga ratio and by inserting the Cu2+ during the synthesis of the zeolite. Remarkably, the Cu-loaded Ga-CHA catalysts demonstrated a consistently lower selectivity to N2O by-product formation compared to Al-CHA because of a lower tendency for NO oxidation. |
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ISSN: | 0926-860X 1873-3875 |
DOI: | 10.1016/j.apcata.2021.118326 |