Reversible NOx storage over Ru/Na-Y zeoliteSmeekens, S., Heylen, S., Villani, K., Houthoofd, K., Godard, E., Tromp, M., Seo, J. W., DeMarco, M., Kirschhock, C. E. A. & Martens, J. A., 2010, In : Chemical Science. 1, 6, p. 763-771 9 p.
Research output: Contribution to journal › Article › Academic › peer-review
Ruthenium loaded Na-Y zeolite was found to be an efficient adsorbent for achieving NOx adsorption-desorption cycles comprising adsorption under oxidizing and desorption under reducing conditions. The speciation of ruthenium was investigated using TEM, EXAFS, Ru-99 Mossbauer spectroscopy and XRD in combination with Rietveld refinement. The sodium cation siting was monitored using Na-23 MAS NMR. Characterization of the Ru/Na-Y adsorbent in NOx saturated and regenerated state revealed a unique cooperation of supported ruthenium nano metal particles and isolated Ru atoms in framework cavities affecting the sodium cations. Supported ruthenium nanoparticles assume a catalytic role in NO oxidation. Ruthenium atoms in framework cavities undergo switching of oxidation state during adsorption-desorption cycles. It triggers reversible sodium cation migrations from coordination with the framework in the regenerated state to coordination in sodium-water networks in supercages providing adsorption sites for NOx during adsorption. The peculiar ruthenium organization is naturally obtained upon lean-rich cycling. Ru/Na-Y adsorbent is insensitive to SOx and to the presence of CO during reductive regeneration.
|Number of pages||9|
|Publication status||Published - 2010|
- SELECTIVE CATALYTIC-REDUCTION, RUTHENIUM CATALYSTS, REACTION-MECHANISM, TRANSITION-METAL, NITROGEN-OXIDES, EXHAUST-GAS, ADSORPTION, DENO(X), STATE, CHEMISTRY