Catalytic property of A(2)(II)B(II)B(VI)O(6) double perovskites (B-VI = Mo, W) for the reduction of nitric oxide with propane in the presence of oxygen
Md. Wei et al., Catalytic property of A(2)(II)B(II)B(VI)O(6) double perovskites (B-VI = Mo, W) for the reduction of nitric oxide with propane in the presence of oxygen, MATER RES B, 35(4), 2000, pp. 521-530
Systematic series of double perovskites containing W and Mo, A(2)(II)B(II)B
(VI)O(6) (A(II) = Ba, Sr, Ca; B-II = Mg, Ca, Co, Ni, Cu, Cd; B-VI = W, Mo,
W1-xMox) were synthesized, and their catalytic activities for NO-C3H8-O-2 r
eaction were investigated. All the oxides crystallized in the ordered doubl
e perovskite structure with the rock-salt arrangement of B-II and B-IV cati
ons, and the unit cell symmetry was almost exclusively determined by A(II)
cations. The double perovskites catalyzed the nonselective reduction of NO
into N2O and occasionally N-2 specifically at 600 degrees C in the gaseous
mixture of NO (0.44%), C3H8 (0.29%) and O-2 (4.4%). The reduction activity
of NO into N2O and N-2 depended on the sort of A(II), B-II, and B-VI cation
s, but the effect of B-II cations was the most remarkable. The NO reduction
activity increased monotonically with an increase in the enthalpy of forma
tion of (BO)-O-II (-Delta H-f(o)), suggesting that the strength of B-II-O b
ond or the redox property of B-II ions is of primary importance for the NO
reduction activity in the NO-C3H8-O-2 reaction. (C) 2000 Elsevier Science L
td. All rights reserved.