Redox behaviour and catalytic properties of Ce0.5Zr0.5O2-supported palladium catalysts Original Research Article

Ce0.5Zr0.5O2-supported palladium catalysts were prepared and used for CO and methane oxidation. The redox behaviour of these catalysts was investigated by using H2-TPR and CO-TPR. The shape and temperature of TPR peaks depend on the nature of reducing agent. Two peaks (α1 and γ) were observed when H2 was used as reducing agent for the fresh catalyst, while three peaks (α′, β′ and γ′) were observed when CO was used as a reducing agent. The addition of a noble metal effectively promotes the reduction of Ce0.5Zr0.5O2 support, which is attributed to hydrogen spillover. After re-oxidation treatments, the PdO reduction process splits into two peaks (α1 and α2). On the basis of the catalytic activity and CO-TPR results, the activity of CO oxidation is related to the finely dispersed PdO, while the activity of methane oxidation is related to the large PdO particles.