In Situ Attenuated Total Reflection Infrared (ATR-IR) Study of the Adsorption of NO2-, NH2OH, and NH4+ on Pd/Al2O3 and Pt/Al2O3

Ebbesen, Sune D. and Mojet, Barbara L. and Lefferts, Leon (2008) In Situ Attenuated Total Reflection Infrared (ATR-IR) Study of the Adsorption of NO2-, NH2OH, and NH4+ on Pd/Al2O3 and Pt/Al2O3. Langmuir, 24 (3). pp. 869-879. ISSN 0743-7463

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Abstract:	In relation to the heterogeneous hydrogenation of nitrite, adsorption of NO2-, NH4+, and NH2OH from the aqueous phase was examined on Pt/Al2O3, Pd/Al2O3, and Al2O3. None of the investigated inorganic nitrogen compounds adsorb on alumina at conditions presented in this study. NO2-(aq) and NH4+(aq) on the other hand show similar adsorption characteristics on both Pd/Al2O3 and Pt/Al2O3. The vibrational spectrum of the NO2- ion changed substantially upon adsorption, clearly indicating that NO2- chemisorbs onto the supported metal catalysts. On the contrary, adsorption of NH4+ does not lead to significant change in the vibrational spectrum of the ion, indicating that the NH4+ ion does not chemisorb on the noble metal but is stabilized via an electrostatic interaction. When comparing the adsorption of hydroxylamine (NH2OH(aq)) on Pd/Al2O3 and Pt/Al2O3, significant differences were observed. On Pd/Al2O3, hydroxylamine is converted into a stable NH2(ads) fragment, whereas on Pt/Al2O3 hydroxylamine is converted into NO, possibly via HNO(ads) as an intermediate.
Item Type:	Article
Copyright:	© 2008 American Chemical Society
Faculty:	Science and Technology (TNW)
Research Group:	Catalytic Processes and Materials (CPM)
Link to this item:	http://purl.utwente.nl/publications/59329
Official URL:	http://dx.doi.org/10.1021/la7027725
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