摘要
以程序升温硫化（ＴＰＳ）和硫化态催化剂的原位ＴＰＤ技术表征了γ－Ａｌ２Ｏ３载体上分别以１２－钨硅酸（ＳｉＷ１２）和偏钨酸铵为前身物所得两系列催化剂的硫化行为和表面活性氢脱附特性．结果表明，以ＳｉＷ１２为前身物时，由于钨物种以单一的八面体配位形态存在，相应催化剂的硫化温度明显降低，深度硫化温度范围显著变窄；同时，当催化剂中钨含量较小时，相应硫化态催化剂上活性氢的脱附量与以偏钨酸铵为前身物的催化剂相比明显增加．这一结果与其加氢脱氮活性有较好的一致性．
Two series catalyst(Ⅰ) and (Ⅱ) prepared from 12-silicotungstic acid(SiW12) and NH4-metatungstate as precursor respectively have been characterized by using temperature-programmed sulfiding (TPS) and in situ TPDtechniques. The results show that: (1) The sulfiding temperature of catalyst (Ⅰ) greatly decreased, especially the deep sulfiding temperature region became much marrower comparing with that of catalyst (Ⅰ).It means that catalyst prepared from SiW12 is readily sulfided. (2) The intensity of hydrogen desorption peak at 493 K, which is considered to be the active hydrogenon the sulfided catalyst surface, on sulfided catalyst (Ⅰ) is higher than thaton catalyst (Ⅱ). This difference is more obvious when WO3 content is lower. (3) HDN measurement demonstrates that catalyst (Ⅰ) exhibited higheractivity for HDN. All of these phenomena can be interpreted by the fact thatonly octahedral coordination tungsten species exist on catalyst (Ⅰ), whichare readily sulfided and form active phase, while tetrahedral coordination. tungsten species can be formed, except octahedral coordination on catalyst(Ⅰ), which is considered to be nonactive species.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
1996年第2期144-148,共5页
基金
博士后科学基金
关键词
钨硅酸
偏钨酸铵
加氢
脱氮
硫化
脱附
催化剂
WSx/γ-Al2O3, 12-silicotungstic acid, ammonium metatungstate, hydrodenitrogenation, active hydrogen, sulphidization,desorption
