Catalytic property of AII2BIIBVIO6 double perovskites (BVI = Mo, W) for the reduction of nitric oxide with propane in the presence of oxygen

Abstract Systematic series of double perovskites containing W and Mo, A II 2 B II B VI O 6 (A II = Ba, Sr, Ca; B II = Mg, Ca, Co, Ni, Cu, Cd; B VI = W, Mo, W 1−x Mo x ) were synthesized, and their catalytic activities for NO–C 3 H 8 –O 2 reaction were investigated. All the oxides crystallized in the ordered double perovskite structure with the rock-salt arrangement of B II and B VI cations, and the unit cell symmetry was almost exclusively determined by A II cations. The double perovskites catalyzed the nonselective reduction of NO into N 2 O and occasionally N 2 specifically at 600°C in the gaseous mixture of NO (0.44%), C 3 H 8 (0.29%) and O 2 (4.4%). The reduction activity of NO into N 2 O and N 2 depended on the sort of A II , B II , and B VI cations, but the effect of B II cations was the most remarkable. The NO reduction activity increased monotonically with an increase in the enthalpy of formation of B II O (−ΔH f °), suggesting that the strength of B II –O bond or the redox property of B II ions is of primary importance for the NO reduction activity in the NO–C 3 H 8 –O 2 reaction.