硫化CoMo/Al_2O_3催化剂上H_2同时催化还原SO_2和NO(Ⅱ)——催化反应活性相及机理探讨  

Simultaneous Reduction of SO_2 and NO by H_2 over Sulfided CoMo/Al_2O_3 Catalyst(Ⅱ):Active Phases and Mechanism

作　　者：朱鹏[1] 李雪辉[2] 王芙蓉[2] 王乐夫[2] 

机构地区：[1]上海应用技术学院,上海200235 [2]华南理工大学化学与化工学院,广州510640

出　　处：《无机化学学报》2008年第12期1975-1982,共8页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.20476032);广东省自然科学基金(No.06025654)项目资助。

摘　　要：主要通过XPS表征、热力学计算以及一系列设计的评价实验等方法,对硫化CoMo/Al2O3催化剂上H2同时催化还原SO2和NO反应的活性相、吸附活性位以及反应机理进行了研究。结果表明,金属硫化物相是SO2和NO转化的主要活性相,并与载体Al2O3共同承担H2S转化为单质硫的作用。此外,反应过程中产生的晶格空位也对NO转化起着重要作用。催化剂表面的阴离子空位是SO2和NO共同的吸附活性位,SO2对NO的吸附有抑制作用,而催化剂表面的L碱位也是SO2的吸附活性位,NO可促进SO2的氧化吸附。最后,本文从反应分子的吸附与活化、NO的转化及晶格硫的流失、SO2还原到H2S、H2S的转化、晶格硫的补充等5个方面提出了反应机理。The active phases, active sites for adsorption and reaction mechanism for simultaneous reduction of SO2 and NO by H2 over sulfided CoMo/Al2O3 catalyst were investigated by XPS, thermodynamic calculation and a series of experiments. The results showed that the metal sulfides were the main active phases for conversion of SO2 and NO, and they also played a role together with Al2O3 support in the conversion of HES to sulfur. In addition, the surface vacant sites formed in the reaction were important for the conversion of NO. The anion vacant sites on the surface of the catalyst were shared by SO2 and NO, while SO2 inhibited the adsorption of NO. The L-base sites on the surface of the catalyst were also the active sites for adsorption of SO2, and NO could promote its adsorption. Finally, the reaction mechanism was proposed from the aspects of adsorption and activation, conversion of NO as well as the loss of lattice sulfur, reduction of SO2 to H2S, conversion of H2S, supply of lattice sulfur.

关 键 词：钴 钼 氧化铝 氢气 二氧化硫 一氧化氮 催化还原 反应机理 

分 类 号：O614.612[理学—无机化学] O614.812[理学—化学]