Framework Co(II) in CoAPO-5

Abstract

Spectroscopic studies by UV–Vis, X-ray absorption and EPR of well crystalline samples of CoAPO-5 containing up to 1.6 atom% Co show no evidence for oxidation of framework substituted Co(II) on calcining, and the reported anomalous temperature dependence of the Co(II) EPR signal in calcined samples could not be reproduced. It is concluded that CoAPO-5, in the absence of extra-framework cobalt, has no redox properties.

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