Effect of strontium substitution on the activity of La_2-xSr_xNiO₄（x=0.0-1.2）in NO decomposition

摘要

The aim of this work is to study the effect of Sr substitution on the redox properties and catalytic ac- tivity of La2-xSrxNiO4(x=0.0-1.2)for NO decomposition.Results suggest that the x=0.6 sample shows the highest activity.The characterization(TPD,TPR,etc.)of samples indicates that the x=0.6 sample possesses suitable abilities in both oxidation and reduction,which facilitates the proceeding of oxygen desorption and NO adsorption.At temperature below 700℃,the oxygen desorption is difficult, and is the rate-determining step of NO decomposition.With the increase of reaction temperature(T 700℃),the oxygen desorption is favorable and,the active adsorption of NO on the active site(NO+Vo+ Ni2+→NO~--Ni3+)turns out to be the rate-determining step.The existence of oxygen vacancy is the prerequisite condition for NO decomposition,but its quantity does not relate much to the activity.