Studies on the Developement of Active Components and their Charactrization of 3-Way Catalysts for Autombile Emission Control -Studies on the surface Characterstics Changes of Pd/$\gamma$-Alumina Catalysts by Addition of WO$_3$ and La$_2$O$_3$ as Promoters-

자동차 배기정화용 3원촉매정화기의 국산화 시도를 위한 촉매성분의 개발과 그 촉매 특성에 관한 연구 -WO$_3$ 및 La$_2$O$_3$조촉매성분들의 첨가에 따른 Pd/$\gamma$-Alumina 촉매들의 표면특성 변화-

For the purpose of suggesting the thermal resistant catalyst for automobile emission control, various catalysts, Pd-WO3 and PD-La2O3 systems, were charactrized before and after thermal aging. It was found that La2O3 formed amorphous surface compound on the support by strong metal-support interaction(SMSI). And by Temperature Programmed Desorption (TPD) expeiment, it was found that the distribution of acid site which is strong acid sites by adding the promoters. After thermal aging, it was observed that the acidity of Pd-WO3 system was decreased largely because of losing acid site by metal vaporization. On the other hand, there was pretty small change in the properties of matter of Pd-La2O3 system. Therefore, it could be considered that La2O3 formed heat resisting amorphous surface compound on the support by SMSI.