磷化钨催化剂前体的H_2—TG分析  

H_2-TG for Tungsten Phosphide Catalyst Precursors

作　　者：李翠清[1] 孙桂大[1] 姜剑[1] 

机构地区：[1]北京石油化工学院绿色化学与催化材料研究所

出　　处：《石油化工高等学校学报》2007年第4期16-20,共5页Journal of Petrochemical Universities

基　　金：国家重点基础研究发展规划项目(No.G2000048003);北京市自然基金项目(2052009);北京市教委资助项目(KM200510017003);中国石油化工股份有限公司资助项目(X04009)

摘　　要：以磷酸氢二铵和偏钨酸铵为原料,制备了 WP 前体。分别采用共浸渍法和机械混合法制备了负载量为30%的 WP/γ—Al_2O_3催化剂前体(I—Cat,H—Cat)。采用共浸渍法,分别制备了不同助剂 Ni,Co,V 的负载量为30%的 WP/γ—Al_2O_3催化剂前体(I—Ni—Cat,I—Co—Cat,I—V—Cat),对制备的催化剂前体在一定的氢气氛下进行了热重(TG)分析,探索了 WP 催化剂的制备机理和制备方法,以及助剂对负载型磷化钨催化剂前体磷化还原程度的影响。结果表明,WP 催化剂前体在一定的氢气氛中可以被完全还原磷化为 WP;I—Cat 和 H—Cat 表面的钨物种均不能被完全还原磷化为 WP,在载体表面可能形成了—AI—O—W—P结构的物种。与 H—Cat 相比,I一Cat 表面的 W 物种更难被还原磷化为 WP。助剂 Ni 使 I—Ni—Cat 的起始还原磷化温度明显降低;助剂 Co 使 I—Co—Cat 还原磷化程度提高;而助剂 V 使 I—V—Cat 的还原磷化变得更为困难。Diammonium hydrogen phosphate and ammonium metatungstate were used to prepare WP precursor. The impregnation and mixing methods were used to prepare the WP/γ-Al2O3 precursor with loading of 30% （counting by WO3 ） , respectively. WP/γ-Al2O3 precursors by adding some content of promoter Ni, Co, V with loading of 30% （counting by WOa ） were also prepared with impregnation method, respectively. All catalysts were measured with thermogravimetric（TG）analysis in H, flow. The synthetic process of WP catalyst was studied. The effect of synthetic method and promoter on phosphiding extent of WP/γ-Al2O3 precursor was investigated. The results show that WP precursor can be reduced to WP completely in H2 flow. W species on the surface of WP/γ-Al2O3 precursors prepared by impregnation or mixing methods can not be reduced to WP completely in He flow . A substance with a similar structure of -- Al-- O-- W-- P is probably formed on the support surface. Compared with WP/γ-Al2O3 precursor by mixing method, W species is more difficult to be reduced to WP on the surface of WP/γ--Al2O3 precursor by impregnation method. It suggests that inginating reduced temperature of WP/γ-Al2O3 precursor is obviously decreased by adding promoter nickel（Ni）. Cobalt（Co） increases the phosphiding extent of WP/γ-Al2O3 precursor. Adding vanadium（V） species on the surface of WP/γ-Al2O3 precursor is more different to be reduced to WP.

关 键 词：磷化钨 制备过程 热重分析 载体 助剂 

分 类 号：O643.32[理学—物理化学]