Migration of nickel and titanium oxide species as studied by in situ scanning transmission electron microscopy

https://doi.org/10.1016/0021-9517(86)90200-9Get rights and content

Abstract

The interactions between nickel and titania were studied by in situ scanning transmission electron microscopy during treatments in hydrogen at temperatures near 1000 K. Large nickel particles (e.g., 100 nm) were observed to create pits in the titania films on which they were supported. In addition, the titania films, originally rutile TiO2, were converted to Ti4O7 during treatment in hydrogen at ca. 1000 K. It is suggested that the nickel facilitates reduction of titania in close proximity to the metal particles, thereby leading to the formation of pits in the titania support. The reduced-titania species removed from the support during this process migrate onto and/or into the nickel particles. Evidence is presented that indicates the migration of both nickel and titania may be involved in this process. This mode of migration may be a general phenomenon for metals on reducible supports. The resulting presence of titania species on the metal surface is thought to be responsible for the occurrence of so-called “strong metal-support interactions”

References (47)

  • S.J. Tauster et al.

    J. Catal.

    (1978)
  • M.A. Vannice et al.

    J. Catal.

    (1979)
  • E.I. Ko et al.

    J. Catal.

    (1981)
  • R.T.K. Baker et al.

    J. Catal.

    (1979)
  • R.T.K. Baker et al.

    J. Catal.

    (1979)
  • D.E. Resasco et al.

    Appl. Catal.

    (1983)
  • D.E. Resasco et al.

    J. Catal.

    (1983)
  • J. Santos et al.

    J. Catal.

    (1983)
  • R. Burch et al.

    J. Catal.

    (1982)
  • X-Z. Jiang et al.

    J. Catal.

    (1985)
  • L.M. Tau et al.

    J. Catal.

    (1984)
  • L.L. Murrell et al.

    Stud. Surf. Sci. Catal.

    (1981)
  • C.S. Ko et al.

    J. Catal.

    (1984)
  • J.A.A. Cairns et al.

    J. Catal.

    (1983)
  • H.R. Sadeghi et al.

    J. Catal.

    (1984)
  • A.J. Simoens et al.

    J. Catal.

    (1984)
  • R.T.K. Baker et al.

    J. Catal.

    (1985)
  • R.T.K. Baker et al.

    J. Catal.

    (1983)
  • A.K. Singh et al.

    J. Catal.

    (1985)
  • K. Kunimori et al.

    Stud. Surf. Sci. Catal.

    (1983)
  • T. Huizinga et al.

    Appl. Catal.

    (1984)
  • B.J. Tatarchuk et al.

    J. Catal.

    (1981)
  • C.S. Ko et al.

    J. Catal.

    (1984)
  • Cited by (53)

    • Enhanced dielectric properties of Ag-doped CCTO ceramics for energy storage devices

      2017, Ceramics International
      Citation Excerpt :

      Also, there are various ways to reduce the sintering temperature in order to lower the fabrication costs and improve the density of the ceramic material, such as to incorporate glass fritz, incorporate a metallic material, and employ nano-sized powders. In the case of incorporating the metallic material, silver, manganese and nickel are generally used as sintering aid materials [5–7]. The incorporation of a metallic material is suggested to depress the oxygen vacancy and relieve the internal stresses to result in an excellent enhancement of the relative dielectric permittivity [8–10].

    • Stabilizing cobalt catalysts for aqueous-phase reactions by strong metal-support interaction

      2015, Journal of Catalysis
      Citation Excerpt :

      The so-called strong metal-support interaction (SMSI) effect has been reported to be due to migration of partially reduced metal oxide species onto the surface of metal particles [33–37]. Dumesic et al. monitored the changes in physical and chemical properties of a NiTiO2 system during reaction in hydrogen using transmission electron microscopy (TEM) [38]. Zander et al. have recently observed the formation of a ZnO layer covering copper particles upon reduction by means of a depth-sensitive synchrotron X-ray photoelectron spectroscopy (XPS) [39].

    • Deactivation of supported nickel catalysts during CO methanation

      2014, Applied Catalysis A: General
      Citation Excerpt :

      Partial reduction of the TiO2 support could also have a contribution, in a minor extent, to the TPR profiles. These two phenomena have also been observed in several literature studies [27,39–48]. The average Ni particle diameter was estimated both from hydrogen static chemisorption and X-ray diffraction measurements.

    • Growth of carbon nanotube forests between a bi-metallic catalyst layer and a SiO<inf>2</inf> substrate to form a self-assembled carbon-metal heterostructure

      2012, Carbon
      Citation Excerpt :

      When the sample is exposed to the N2/H2 atmosphere at a temperature of around 600 °C, native Ni oxide, which was formed due to exposure to ambient prior to process, becomes reduced (supporting information D – reactions VI–VIII). The availability of atomic hydrogen was included in considerations since Ni is known to unfold strong catalytic effects leading to dissociation of H2 on its surface [28]. Experimentally, the reduction of oxidized Ni was confirmed to take place already at rather low temperatures (e.g., from ∼200 °C for powder sample in H2 atmosphere [29]).

    View all citing articles on Scopus
    View full text