Dopants adsorbed as single atoms prevent degradation of catalysts

Sanwu Wang, Albina Y. Borisevich, Sergey N. Rashkeev, Michael V. Glazoff, Karl Sohlberg, Stephen J. Pennycook, Sokrates T. Pantelides

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153 Citations (Scopus)

Abstract

The design of catalysts with desired chemical and thermal properties is viewed as a grand challenge for scientists and engineers1. For operation at high temperatures, stability against structural transformations is a key requirement. Although doping has been found to impede degradation, the lack of atomistic understanding of the pertinent mechanism has hindered optimization. For example, porous γ-Al2O3, a widely used catalyst and catalytic support2-6, transforms to non-porous α-Al2O3 at ∼1,100°C (refs 7-10). Doping with La raises the transformation temperature8-11 to ∼1,250°C, but it has not been possible to establish if La atoms enter the bulk, adsorb on surfaces as single atoms or clusters, or form surface compounds10-15. Here, we use direct imaging by aberration-corrected Z-contrast scanning transmission electron microscopy coupled with extended X-ray absorption fine structure and first-principles calculations to demonstrate that, contrary to expectations, stabilization is achieved by isolated La atoms adsorbed on the surface. Strong binding and mutual repulsion of La atoms effectively pin the surface and inhibit both sintering and the transformation α-Al2O3. The results provide the first guidelines for the choice of dopants to prevent thermal degradation of catalysts and other porous materials.

Original languageEnglish
Pages (from-to)143-146
Number of pages4
JournalNature Materials
Volume3
Issue number3
DOIs
Publication statusPublished - Mar 2004

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ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Wang, S., Borisevich, A. Y., Rashkeev, S. N., Glazoff, M. V., Sohlberg, K., Pennycook, S. J., & Pantelides, S. T. (2004). Dopants adsorbed as single atoms prevent degradation of catalysts. Nature Materials, 3(3), 143-146. https://doi.org/10.1038/nmat1077