Study of the Ru/Ce system in the oxidation of carbon black and volatile organic compounds

The relationship between the state of Ru on CeO2 and catalytic activity in the oxidation of carbon black (CB) and some volatile organic compounds (VOCs) was investigated for Ru/CeO2 catalysts prepared by wet impregnation. It was demonstrated that the addition of ruthenium to ceria significantly improved the reactivity of the latter. The temperature programmed reduction (TPR) experiments of Ru/CeO2 showed that the oxygen species of RuO2 was reduced at low temperatures. In addition, Electronic Paramagnetic Resonance (EPR) studies of outgassed samples at different temperatures showed an anisotropic signal indicating that Ru(IV) was reduced to intermediate valence states like Ru(III) before its total reduction to metallic Ru. It was concluded that Ru-O-Ce bonds in the well-dispersed Ru species are highly fragile and its mobile oxygen is the active species in the catalytic oxidation process.