The formation of copper aluminate by solid-state reaction

Abstract

Solid-state reactions between bulk samples of copper oxide and alumina have been studied using scanning electron microscopy and electron microprobe analysis. Both CuAl 2 O 4 and CuA10 2 were found to form during reactions in air at 1100 °C between CuO powder and single-crystal alumina substrates. The relative position of the CuAl 2 O 4 and CuA10 2 layers was observed to depend on the crystallographic orientation of the surface of the alumina substrate: CuAl 2 O 4 formed in contact with (0001) alumina substrates while CuA10 2 formed when the alumina substrate surface was (1120). Faceted Cu-amminate/alumina phase boundaries were observed to develop when single-crystal alumina rods were reacted with CuO, although the interfaces invariably tended to be wavy.

Aqueous phase catalytic oxidation of phenol in a trickle bed reactor: effect of the pH

“…On the other hand, the treatment at high temperature, e.g. a calcination temperature of 4008C, of a mixture of copper and aluminum oxides forms copper aluminate (Susnitzky and Barry Carter, 1991) that is more resistant to the acidic medium but is less catalytically active than the``free'' copper oxide (Alejandre et al, 1998). The attempt to modify the distribution of copper species in the catalyst by varying the atmosphere calcination was unsuccessful as discussed above.…”

Dellafossite CuAlO2 film growth and conversion to Cu–Al2O3 metal ceramic composite via control of annealing atmospheres

“…The relative intensity of the CuAlO 2 diffraction peaks vary substantially as compared to the reference powder spectra shown in figure 1 (a) (11)(12)(13)(14)(15)(16)(17)(18)(19)(20). 25 In this work, the polycrystalline Al 2 O 3 substrates used have x-ray 15 reflections corresponding to both the (0001) and (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) planes and these are used in conjunction with CuO thereby satisfying conditions identified in previous work for both CuAl 2 O 4 and CuAlO 2 formation. However, our results in figure 4 below show that, post annealing, only a very small fraction of the films are in 20 the spinel phase.…”

“…Each scan lasted 8 minutes and the 2θ range 30 -40° was chosen as all the 25 components of interest have reasonably strong reflections in this range. At higher temperatures, thermal expansion effects shift the peak positions with respect to room temperature, however the substrate peak provides a useful reference point for the identification of the other components.…”

“…[1][2][3] The discovery of intrinsic wide bandgap p-type conduction in the dellafossite material CuAlO 2 represents an 25 important step towards realising these technologies. 4 In addition CuAlO 2 as been demonstrated as an effective catalyst for solar water splitting and chlorine production and may also have applications in low power field emission based displays and in sensor technologies.…”

Density Functional Theory Investigation into the B and Ga Doped Clean and Water Covered γ-Alumina Surfaces

“…The -alumina is an important material in chemistry and materials science due to its widespread applications in chemical industry [1][2][3], ceramics, and semiconductors [4][5][6][7]. In order to improve the performance of the material, some heteroatoms were usually chosen to be incorporated into the -alumina bulk and surfaces [8,9].…”