Jump to main content
Jump to site search

Issue 114, 2016
Previous Article Next Article

The interaction between CuO and Al2O3 and the reactivity of copper aluminates below 1000 °C and their implication on the use of the Cu–Al–O system for oxygen storage and production

Author affiliations

Abstract

The reversible decomposition of CuO into Cu2O and oxygen at high temperature, typically between 850 and 1000 °C, provides a means of separating pure oxygen from air. In such a process, the oxide generally has to be supported on a refractory oxide, e.g. alumina, to maintain its capacity when cycled many times between CuO and Cu2O. One problem is that if the CuO reacts with the alumina to form CuAl2O4, the latter releases oxygen too slowly to be of practical use so that the capacity for oxygen release of such a carrier falls progressively as more aluminate is formed. However, the reported temperatures at which CuAl2O4 forms are inconsistent so far. This work sets out to investigate the interaction between CuO and different aluminas (and precursors), which are commonly used as support materials, at temperatures between 700 and 1000 °C, as well as some chemical properties of the resulting copper aluminates. It was found that the formation of CuAl2O4 occurred at around 700 °C, 800 °C and 950 °C, when amorphous aluminium hydroxide, γ-alumina, and α-alumina were used as the source of alumina support, respectively. The decomposition of CuAl2O4 in an oxygen-lean environment can lead to the formation of α-alumina as well as γ-alumina, depending on the partial pressure of oxygen. Given that the α-form does not react with CuO around 900 °C, the typical operating temperature for the CuO/Cu2O couple, this observation can be used to partially regenerate CuO from CuAl2O4, for oxygen storage and production at this temperature by decomposing the spinel in a controlled atmosphere to form only α-alumina. However, during the decomposition of CuAl2O4, delafossite CuAlO2 is also formed, limiting the amount of Cu that could be recovered as CuO in a single process cycle.

Graphical abstract: The interaction between CuO and Al2O3 and the reactivity of copper aluminates below 1000 °C and their implication on the use of the Cu–Al–O system for oxygen storage and production

Back to tab navigation

Supplementary files

Publication details

The article was received on 11 Sep 2016, accepted on 21 Nov 2016 and first published on 22 Nov 2016


Article type: Paper
DOI: 10.1039/C6RA22712K
Citation: RSC Adv., 2016,6, 113016-113024
  • Open access: Creative Commons BY license
  •   Request permissions

    The interaction between CuO and Al2O3 and the reactivity of copper aluminates below 1000 °C and their implication on the use of the Cu–Al–O system for oxygen storage and production

    W. Hu, F. Donat, S. A. Scott and J. S. Dennis, RSC Adv., 2016, 6, 113016
    DOI: 10.1039/C6RA22712K

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements