A pronounced catalytic activity of LaCu oxide supported on ZrO 2 for reaction between nitrogen monoxide and carbon monoxide

Abstract

The reductions of nitrogen monoxide (NO) by carbon monoxide (CO) and hydrocarbon are the fundamental reaction pathways for the removal of NO{sub x} from automobile exhaust. Therefore, it is meaningful from the standpoint of basic research to develop and investigate a high-activity catalyst for the reduction of NO by CO, although for the actual exhaust the effects of H{sub 2}O and SO{sub 2} cannot be ignored. It has been reported that copper-containing mixed oxides having perovskite related structures such as Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y}, YBa{sub 2}Cu{sub 3}O{sub y{prime}}, and La{sub 2}CuO{sub 4}show high catalytic activities for the reaction between NO and CO and that the catalysts having the valence of copper ion close to two are active for the reaction. The authors have reported that the perovskite-type mixed oxide, LaCoO{sub 3}, can be highly dispersed on ZrO{sub 2} and gave an enhanced catalytic activity. ZrO{sub 2} is also known as a suitable substrate for preparing copper-containing superconducting oxide films. They attempted in this study to prepare La{sub 2}CuO{sub 4} highly dispersed on the surface of ZrO{sub 2} and obtained a very high catalytic activity for the reaction between NO and CO.