载体对负载型磷化钨催化剂性能的影响

 摘要：采用在H2中程序升温还原负载的磷钨酸盐的方法，合成了不同载体(SiO2、TiO2、γ-Al2O3及其二元复合氧化物γ-Al2O3-SiO2、γ-Al2O3-TiO2、SiO2-TiO2)负载的磷化钨催化剂。通过TG-DTA法研究了还原磷化过程，采用BET、NH3-TPD和XPS等技术表征了合成的催化剂，评价了催化剂的噻吩、吡啶、二苯并噻吩和咔唑的催化活性。γ-Al2O3或含γ-Al2O3的复合氧化物载体使负载型磷化钨催化剂前体的还原磷化变得较为困难，不同载体所负载的磷化钨催化剂的比表面积、表面酸量和催化剂表面P和W的价态分布以及加氢精制活性均有较大差别。TiO2载体对活性W物种具有很好的稳定作用，WP/TiO2催化剂具有最佳的加氢脱硫(HDS)和加氢脱氮(HDN)催化活性，尤其对二苯并噻吩HDS和咔唑HDN催化活性更好。

EFFECT OF SUPPORTS ON THE PERFORMANCE OF SUPPORTED TUNGSTEN PHOSPHIDE CATALYSTS

Abstract: Supported WP catalysts with SiO2,TiO2, γ-Al2O3 , γ-Al2O3-SiO2, γ-Al2O3-TiO2 and SiO2-TiO2 as support were synthesized by phosphiding with H2 in process of temperature-programmed reduction and characterized by BET, NH3-TPD and XPS. Their hydrotreating performances were investigated and the effect of supports on physicochemical properties and catalytic performance of the catalysts was studied. The phosphiding process of supported WP catalyst precursors was investigated by TG-DTA. γ-Al2O3, γ-Al2O3-SiO2 and γ-Al2O3-TiO2 supports could cause difficulty for phosphoding of their supported WP catalyst precursors. BET surface area, acid amount, surface W valence and hydrotreating performance of the supported WP catalyst were different with different supports. The TiO2 support could stabilize active W species on its surface, so the WP/TiO2 catalyst possessed highest activities for HDS and HDN, especially for DBT HDS and carbazole HDN.