Electron paramagnetic resonance study of the effect of temperature upon copper-impregnated titanium dioxide powders

Abstract

Polycrystalline powders of both anatase and rutile TiO₂ have been impregnated with copper(II) ions and subjected to calcination at temperatures up to 950 °C. Using electron paramagnetic resonance, surface-bound copper(II) ions have been detected on the impregnated samples. Calcination above 750 °C allows the copper to enter the lattice structure of both the anatase and rutile forms.

A hydrous precursor pulp of TiO₂ was doped with Cu²⁺ and also subjected to temperatures up to 950 °C. Axially symmetric EPR spectra were found for samples heated at 750 °C and were attributed to Cu²⁺ substitutionally incorporated within an anatase crystal host. ⁶³Cu-enriched copper was used to assist in the understanding of the observed spectra.