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- Pingel, Torben, 1984, et al.
(author)
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Three-dimensional probing of catalyst ageing on different length scales: A case study of changes in microstructure and activity for CO oxidation of a Pt-Pd/Al2O3 catalyst
- 2017
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In: ChemCatChem. - : Wiley. - 1867-3899 .- 1867-3880. ; 9:18, s. 3544-3553
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Journal article (peer-reviewed)abstract
- In the present study the effects of thermal treatment on the microstructure of a Pt-Pd/Al2O3 oxidation catalyst and its activity for CO oxidation have been studied. The microstructural analysis was performed using several high-resolution electron microscopy techniques like STEM, FIB/SEM slice & view, SEM and EDX. A combination of these analysis techniques and advanced TEM specimen preparation allowed for three-dimensional probing at different length scales avoiding the random character of conventionally crushed powder specimens due to site specificity. A core-shell distribution of Pt-Pd nanoparticles within the alumina support particles, with enlarged nanoparticles (≈ 1.5 to 40 nm) being present in the shell and small nanoparticles (
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| 2. |
- Zeng, Lunjie, 1983, et al.
(author)
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Correlation between Electrical Transport and Nanoscale Strain in InAs/In0.6Ga0.4As Core-Shell Nanowires
- 2018
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In: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 18:8, s. 4949-4956
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Journal article (peer-reviewed)abstract
- Free-standing semiconductor nanowires constitute an ideal material system for the direct manipulation of electrical and optical properties by strain engineering. In this study, we present a direct quantitative correlation between electrical conductivity and nanoscale lattice strain of individual InAs nanowires passivated with a thin epitaxial In0.6Ga0.4As shell. With an in situ electron microscopy electromechanical testing technique, we show that the piezoresistive response of the nanowires is greatly enhanced compared to bulk InAs, and that uniaxial elastic strain leads to increased conductivity, which can be explained by a strain-induced reduction in the band gap. In addition, we observe inhomogeneity in strain distribution, which could have a reverse effect on the conductivity by increasing the scattering of charge carriers. These results provide a direct correlation of nanoscale mechanical strain and electrical transport properties in free-standing nanostructures.
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