Hostname: page-component-8448b6f56d-dnltx Total loading time: 0 Render date: 2024-04-25T00:41:02.526Z Has data issue: false hasContentIssue false
  • English
  • Français

Aberration-Corrected STEM Imaging of Ag on γ-Al2O3

Published online by Cambridge University Press:  21 December 2007

Douglas A. Blom ,
Lawrence F. Allard ,
Chaitanya K. Narula  and
Melanie J. Moses-DeBusk
Douglas A. Blom
Affiliation:
Oak Ridge National Laboratory, Materials Science & Technology Division, Oak Ridge, TN 37831-6064, USA
Lawrence F. Allard
Affiliation:
Oak Ridge National Laboratory, Materials Science & Technology Division, Oak Ridge, TN 37831-6064, USA
Chaitanya K. Narula
Affiliation:
Oak Ridge National Laboratory, Materials Science & Technology Division, Oak Ridge, TN 37831-6064, USA
Melanie J. Moses-DeBusk
Affiliation:
Oak Ridge National Laboratory, Materials Science & Technology Division, Oak Ridge, TN 37831-6064, USA
Get access

Abstract

Ag on γ-alumina is a promising catalyst for hydrocarbon selective catalytic reduction in lean-burn gasoline and diesel engines for transportation applications. Although much is known about the mechanism of NOx reduction and the various intermediates, little agreement exists on the nature of the active silver species. In the present work, aberration-corrected STEM has provided new information about the nature of Ag on alumina both as impregnated and following treatments at various temperatures with exposure to simulated exhaust gas. Ex situ techniques have provided new insights into the evolution of Ag on alumina following exposure to temperature and simulated exhaust gas.

Keywords

aberration-corrected scanning transmission electron microscopyhigh-angle annular dark-field imaginglean NOx catalystsingle-atom imagingatomic resolutionex situ STEM
Type
Research Article
Information
Microscopy and Microanalysis , Volume 14 , Issue 1: Special Issue: Materials Research in an Aberration-Free Environment , February 2008 , pp. 98 - 103
Copyright
© 2008 Microscopy Society of America

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Arve, K., Čapek, L., Klingstedt, F., Eränen, K., Lindfors, L.E., Murzin, D.Y., Dědeček, J., Sobalik, Z. & Wichterlová, B. (2004). Preparation and characterization of Ag/alumina catalysts for the removal of NOx emissions under oxygen rich conditions. Top Catal 30/31, 91–95.Google Scholar
Arve, K., Klingstedt, F., Eränen, K., Murzin, D.Y., Čapek, L., Dědeček, J., Sobalik, Z., Wichterlová, B., Svennerberg, K., Wallenberg, L.R. & Bovin, J.O. (2006). Analysis of the state and size of silver on alumina in effective removal on NOx from oxygen rich exhaust gas. J Nanosci Nanotech 6, 1076–1083.Google Scholar
Blom, D.A., Allard, L.F., Mishina, S. & O'Keefe, M.A. (2006). Early results from an aberration-corrected JEOL 2200FS STEM/TEM at Oak Ridge National Laboratory. Microsc Microanal 12, 483–491.Google Scholar
Bogdanchikova, N., Meunier, F.C., Avalos-Borja, M., Breen, J.P. & Pestryakov, A. (2002). On the nature of the silver phases of Ag/Al2O3 catalysts for reactions involving nitric oxide. Appl Catal B Environ 36, 287–297.Google Scholar
Breen, J.P., Burch, R., Hardacre, C. & Hill, C.J. (2002). Structural investigation of the promotional effect of hydrogen during the selective catalytic reduction of NOx with hydrocarbons over Ag/Al2O3 catalysts. J Phys Chem B 109, 4805–4807.Google Scholar
Eränen, K., Klingstedt, F., Arve, K., Lindfors, L.E. & Murzin, D.Y. (2004). On the mechanism of the selective catalytic reduction of NO with higher hydrocarbons over a silver/alumina catalyst. J Catal 227, 328–343.Google Scholar
Haider, M., Uhlemann, S. & Zach, J. (2000). Upper limits for the residual aberrations of a high-resolution aberration-corrected STEM. Ultramicroscopy 81, 163–175.Google Scholar
He, H. & Yu, Y. (2005). Selective catalytic reduction of NOx over Ag/Al2O3 catalyst: From reaction mechanism to diesel engine test. Catal Today 100, 37–47.Google Scholar
Iglesias-Juez, A., Fernández-García, M., Martínez-Arias, A., Schay, Z., Koppány, Z., Hungría, A.B., Fuerte, A., Anderson, J.A., Conesa, J.C. & Soria, J. (2004). Catalytic properties of Ag/Al2O3 catalysts for lean NOx reduction processes and characterization of active silver species. Top Catal 30/31, 65–70.Google Scholar
Jen, H.W. (1998). Study of nitric oxide reduction over silver/alumina catalysts under lean conditions: Effects of reaction conditions and support. Catal Today 42, 37–44.Google Scholar
Martínez-Arias, A., Fernández-García, M., Iglesias-Juez, A., Anderson, J.A., Conesa, J.C. & Soria, J. (2000). Study of the lean NOx reduction of C3H6 in the presence of water over silver/alumina catalysts prepared from inverse microemulsions. Appl Catal B Environ 28, 29–41.Google Scholar
Masuda, K., Tsunjimura, K., Shinoda, K. & Kato, T. (1996). Silver-promoted catalyst for removal of nitrogen oxides from emission of diesel engines. Appl Catal B Environ 8, 33–40.Google Scholar
Miyadera, T. (1993). Alumina-supported silver catalysts for the selective reduction of nitric oxide with propene and oxygen-containing organic compounds. Appl Catal B Environ 2, 199–205.Google Scholar
Narula, C.K., Jen, H.W. & Gandhi, H.S. (2001). Sol-gel alumina membrane for lean NOx catalysis and method of making same. U.S. Patent 6,232,253 B1.
Satakawa, S. (2000). Enhancing the NO/C3H8/O2 reaction by using H2 over Ag/Al2O3 catalysts under lean-exhaust conditions. Chem Lett 3, 294–295.Google Scholar
Satakawa, S., Shibata, J., Shimizu, K., Satsuma, A. & Hattori, T. (2003). Promotion effect of H2 on the low temperature activity of the selective reduction of NO by light hydrocarbons over Ag/Al2O3. Appl Catal B Environ 42, 179–186.Google Scholar
Shibata, J., Shimizu, K., Satokawa, S., Satsuma, A. & Hattori, T. (2003). Promotion effect of hydrogen on surface steps in SCR of NO by propane over alumina-based silver catalysts as examined by transient FT-IR. Phys Chem Chem Phys 5, 2154–2160.Google Scholar
Shimizu, K., Satsuma, A. & Hattori, T. (2000). Catalytic performance of Ag–Al2O3 catalyst for the selective reduction of NO by higher hydrocarbons. Appl Catal B Environ 25, 239–247.Google Scholar