RhCo双金属催化剂的研究 Ⅳ.Rh_2Co_2/Al_2O_3上的吸附中心类型及吸附性能  

Study of RhCo Bimetal Catalysts IV . Forms and Properties of Adsorption Sites on Rh_2Co_2/Al_2O_3

作　　者：陈耀强[1] 曹昭[1] 龚茂初[1] 周建略 陈豫[1] 辛勤[2] 张慧[2] 郭燮贤[2] 

机构地区：[1]四川大学化学系,成都610064 [2]中国科学院大连化学物理研究所,大连116023

出　　处：《化学学报》1997年第7期638-643,共6页Acta Chimica Sinica

基　　金：国家自然科学基金;催化基础研究国家重点实验室基金资助课题

摘　　要：利用CO和NO作为双探针分子对Rh_2Co_2/Al_2O_3的吸附中心类型和吸附性能进行了详细的研究.结果表明Rh_2Co_2/Al_2O_3上存在Rh上的孪生和桥式CO吸附中心以及Co上的线式CO吸附中心.其中Rh上的孪生和桥式CO吸附中心对CO和NO的吸附性能与Rh_4/Al_2O_3上的孪生和桥式CO中心相似.Co上的线式CO吸附中心以预吸附的CO能被NO取代,预吸附的NO不能被CO取代而区别于Rh_4/Al_2O_3上的Rh的线式CO吸附中心;又以既能吸附CO又能吸附NO而不同于Co_2/Al_2O_3和Rh+Co/Al_2O_3上的Co中心.与母体簇的结构相关联,表明H_2还原后的Rh_2Co_2/Al_2O_3上Rh_2Co_2(CO)_(12)簇结构仍保持,且Rh—Co相互作用强.The forms and properties of adsorption sites on Rh2Co2/Al2O3 have been studied in detail by using CO and NO as double probes. The results indicate that there are RhI sites and bridged sites on Rh and linear sites on Co over Rh4/Al2O3. The chemisorption properties of RhI sites and bridged sites on Rh over Rh2Co2/Al2O3 for CO and NO are similar to that over Rh4/ Al2O3. While the chemisorption properties of the linear sites on Co over Rh2Co2/Al2O3 on which preadsorbed CO can be replaced by NO and preadsorbed NO can not be replaced by CO are different from that of linear sites on Rh4/Al2O3 and that of Co sites on Co2/Al2O3 and Rh + Co/ Al2O3. TO relate above results with the structure of original Rh2Co2 (CO)12, it indicate thatRh2Co2(CO)12 impregnated on Al2O3 retain its structure after reduction with H2 at 400℃. The interaction between Rh and Co is strong.

关 键 词：铑 钴 双金属催化剂 催化剂 吸附中心 吸附性能 

分 类 号：O643.36[理学—物理化学]