Co-K-Mo/γ-Al2O3催化剂的合成低碳醇性能及其结构研究

氧化态Ｋ－ＭｏＯ３／γ－Ａｌ２Ｏ３催化剂中添加Ｃｏ（ＮＯ３）２后在空气中四个不同温度下焙烧再硫化,制得Ｃｏ－Ｋ－ＭｏＯ３／γＡｌ２Ｏ３催化剂,对其ＣＯ加氢合成低碳醇的催化反应性能进行了评价,运用ＸＲＤ,ＬＲＳ及ＥＸＡＦＳ等手段对催化剂及其氧化态前躯体的结构进行了表征,活性测试结果表明加Ｃｏ后于５００－６５０℃焙烧制得的催化剂活性较高,且使Ｃ２＋醇比例增加,结构分析结果显示加Ｃｏ后３５０℃焙烧时,Ｃ

Catalytic Properties for Mixed Alcohols Synthesis and Structure of Co-K-Mo/γ-Al2O3

A series of oxidic Co-K-Mo/γ-Al2O3 catalyst samples, prepared by impregnating oxidic K-MoO3/γ-Al2O3 samples with aqueous solution of calculated Co (NO3)2 and then calcination in air at temperatures of 350 ℃, 500℃, 650℃ and 800℃, respectively, were sulfided and then investigated for the synthesis of mixed alcohols from CO hydrogenation at conditions of p=5.0MPa, T=350 ℃ and GHSV=4800h-1. The results demonstrate that the addition of cobalt promoter is favourable to from higher alcohols and the samples calcined at 500-650 ℃ after impregnating Co2+ possess superior properties for the mixed alcohols synthesis.
The structures of Co and Mo species on the oxidic and sulfided samples were determined by XRD, LRS and EXAFS. For oxidic sample calcined at 350 ℃, cobalt exists as Co3O4 species and covers on the surface of K-Mo-O species, the structures of K-Mo-O species are same as that in K-MoO3/7-Al2O3 sample. After sulfidation, cobalt exists as sulfide crystallites with octahedral coordinated Co, and Mo... as MoS2 crystallites. For oxidic samples calcined at 500-650℃, Co component interacts with the K-Mo-O species and destroys the long-range order of the K-Mo-O species gradually. After sulfidation, Co tends to be existed as a sulfide with tetrahedral coordinated Co and Mo still as MoS2 crystallites. For oxidic sample calcined at 800℃, Co component exists mainly as Co(Al2O4) species, most of which can not be sulfided during sulfidation.