Thermal analysis and epr studies of carbon black oxidation in the presence of copper loaded Y2O3-CeO2-ZrO2 catalyst

The activity of copper-free and copper-loaded 10Y2O3-10CeO2-80ZrO2 solid solutions towards carbon black combustion was studied using simultaneous thermogravimetric analysis and differential thermal analysis techniques coupled with gas chromatography. It was demonstrated that all studied catalysts lower the temperature of carbon black combustion. The selectivity of the catalytic reaction in CO2 formation was 100%. The comparison of electron paramagnetic resonance (EPR) spectra of pure catalysts with those of the samples (catalysts mixed with carbon black) after catalysis allowed to evidence, despite of the strong oxidizing atmosphere, a thermal reduction by carbon of Fe3+ (impurities), Cu2+ and Zr4+ during the reaction. Moreover a new EPR signal appeared after catalytic test and was attributed to the presence of paramagnetic metal-carbon or/and metal-sulphur complexes.