Correlation of electrical properties of nanometric copper-doped ceria materials (Ce1 − xCuxO2 − δ) with their catalytic activity in incineration of VOCs

• Nanoemulsion method for synthesis of nanometric monophase ceria system is proposed.
• High catalytic activity is related to high ionic conductivity.
• Share of ionic conductivity in total conductivity is increased with temperature.
• Mars–van Krevellen model of catalytic oxidation is confirmed.

The nanometric copper doped Ce1 − xCuxO2 − δ materials were obtained using a modified reverse nanoemulsion method followed by a previously optimized calcination. XRD patterns confirmed the presence of only one, fluorite-like CeO2 phase, within the range of 0 < x < 0.12, in accordance with embedding Cu ions in the CeO2 phase. High increase of catalytic activity in oxidative incineration of volatile organic compounds (VOCs) with Cu-doping was observed, equally with a high increase in the ionic conductivity related to the increase of concentration of oxygen vacancies in the ceria lattice. The impedance spectroscopy allowed to specify that the high catalytic activity of Ce1 − xCuxO2 − δ is bounded also with change of the share in ionic and electronic conductivities. Though, the active catalyst should reveal mixed ionic and electronic conductivities (MIEC), the higher share of ionic component of electrical conductivity seems to be essential. Such a conclusion is in accordance with the Mars–van Krevellen model of catalytic oxidation of VOC molecules.