Journal article
In situ observation of Cu-Ni alloy nanoparticle formation by X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy: Influence of Cu/Ni ratio
Department of Chemical and Biochemical Engineering, Technical University of Denmark1
CHEC Research Centre, Department of Chemical and Biochemical Engineering, Technical University of Denmark2
Department of Wind Energy, Technical University of Denmark3
Materials science and characterization, Department of Wind Energy, Technical University of Denmark4
Karlsruhe Institute of Technology5
Center for Electron Nanoscopy, Technical University of Denmark6
Department of Physics, Technical University of Denmark7
Surface Physics and Catalysis, Department of Physics, Technical University of Denmark8
Haldor Topsoe AS9
Silica-supported, bimetallic Cu-Ni nanomaterials were prepared with different ratios of Cu to Ni by incipient wetness impregnation without a specific calcination step before reduction. Different in situ characterization techniques, in particular transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS), were applied to follow the reduction and alloying process of Cu-Ni nanoparticles on silica.
In situ reduction of Cu-Ni samples with structural characterization by combined synchrotron XRD and XAS reveals a strong interaction between Cu and Ni species, which results in improved reducibility of the Ni species compared with monometallic Ni. At high Ni concentrations silica-supported Cu-Ni alloys form a homogeneous solid solution of Cu and Ni, whereas at lower Ni contents Cu and Ni are partly segregated and form metallic Cu and Cu-Ni alloy phases.
Under the same reduction conditions, the particle sizes of reduced Cu-Ni alloys decrease with increasing Ni content. Estimates of the metal surface area from sulfur chemisorption and from the XRD particle size generally agree well on the trend across the composition range, but show some disparity in terms of the absolute magnitude of the metal area.
This work provides practical synthesis guidelines towards preparation of Cu-Ni alloy nanomaterials with different Cu/Ni ratios, and insight into the application of different in situ techniques for characterization of the alloy formation. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Language: | English |
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Year: | 2014 |
Pages: | 301-310 |
ISSN: | 18673899 and 18673880 |
Types: | Journal article |
DOI: | 10.1002/cctc.201300628 |
ORCIDs: | Duchstein, Linus Daniel Leonhard , Christensen, Jakob Munkholt , Damsgaard, Christian Danvad , Wagner, Jakob Birkedal and Jensen, Anker Degn |