REFeO~3 (RE=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) were prepared by the complex method with citric acid. The perovskite structure for REFeO~3 was determined with XRD. The Redox mechanism for oxidation of CO was proven by the pulse method of reduction with CO and reoxidation with O~2 over REFeO~3 catalyst. The steady-state kinetics of oxidation for CO has been investigated with external circulation flow reactor. The parameters of kinetic equation were estimated by the method of orthogonal design. The rate constants of reduction for catalysts with CO, k~1, were more than the rate constants of reoxidation for reduced catalysts with O~2, k~2. The ratios of k~1 and k~2 varied within the range of 4.24～133, which showed that the control step for oxidation of CO over REFeO~3 was the reoxidation step of reduced catalyst. The conversions of CO, X~C~O, were more than the conversions of O~2, X~O~2, with pulse method. These pulse data proved the conclusion of control step for the steady-state kinetics. The Redox equation (9) can be simplified to the equation of control step (11). The linear relationship between the rate constants of reduction for catalysts and the reaction rate at the constants of partial pressures P~C~O and P~O~2 over REFeO~3 catalysts was approximately. The oxidation of CO over REFeO~3 has compensation effect.

Key words: KINETICS EQUATIONS, REACTION RATE CONSTANT, ORTHOGONAL DESIGN, PEROFSKITE, GRADIENTLESS REACTOR, XRD