The Generation of Catalytically Active Centres in the Surfaces of α-Al2O3 and α-Cr2O3–Al2O3 Solid Solutions

Abstract

Model processes are described whereby the co-ordination numbers of cations and anions at the surface of the corundum (α-Al₂O₃) structure can be changed whilst still preserving electrical neutrality. A number of distinctive atom groupings can be generated in this way and speculations are made regarding their potential as active centres for heterogeneous catalysis. It is proposed that changes in surface co-ordination number can be induced by replacing Al³⁺ by Cr³⁺ ions, and that the catalytic characteristics will change non-uniformly as the chromium content of the phase α-Cr_xAl_2-xO₃ is progressively increased.