Abstract: ABO2(A=Cu; B=Cr,Al,Fe) complex oxides have been prepared by amorphous citrate precursors method. Formation of singlephase dalofossite structure was confirmed by XRD examination. A conventional fixed-bed micro-reaction technique was used in measuring the catalytic activities of these complex oxides for CO NO reaction under both oxidizing and reducing conditions. CuAlO2 and CuCrO2 show good catalytic activity towards CONO reaction. CuCrO2 was quite stable and no changes in the bulk phase composition were detected even after long time CONO reaction under both oxidizing and reducing conditions. CuAlO2, which was stable enough under oxidizing conditions, was partly reduced to Cu0 after long time catalytic reaction under reducing conditions. Although no phase composition chan ges were detected in CuFeO2 bulk phase after long time catalytic test under oxidizing conditions, partial reduction on the surface can be expected. After catalytic test under reducing conditions, CuFeO2 totally converted to Cu0 and CuFe2O4.Compared with those catalysts of perovskite structure, ABO2 samples show much better catalytic activity for CONO reaction.

Key words: ABO₂, CO-NO reaction, DeNOx catalysts, Dalofossite