Sputtered nano-cobalt on H-USY zeolite for selectively converting syngas to gasoline

Selectively converting CO and H2 to gasoline product （isoparaffin and olefin） in one step still remains a great challenge. We demonstrate effective H-USY zeolite supported nano-cobalt bifunctional catalysts for this catalytic reaction, which are prepared by the novel physical sputtering process. Particles of the sputtered cobalt exist in nano-level and are well-dispersed on acid USY zeolite. Easy activation of the loaded nano-cobalt is also achieved in a low-temperature hydrogen reduction atmosphere. In the tandem catalytic reaction, the sputtered bifunctional Co/USY catalyst exhibits a much higher CO conversion and higher isoparaffin selectiv- ity than the conventional impregnated one. Compared with H-Mor, H-Beta and other zeolites supported catalysts, H-USY zeolite supported cobalt catalyst shows the clearest promotional effect on the activity of FischerTropsch synthesis. The described synthesis herein provides a new pathway to solve the problem caused by the strong metal-support interaction （MSI） in heterogeneous catalysis.

Correlation between hydrocarbon distribution and water-hydrocarbon ratio in Fischer-Tropsch synthesis

In order to shorten the evaluation cycle of cobalt catalyst before the optimized catalyst is fixed on, a mathematical method is proposed to calculate weight percentage of C5＋ hydrocarbons. Based on the carbide polymerization mechanism and the main hydrocarbons being linear alkanes and α-olefins, the correlation between hydrocarbon distribution and the molecular mass ratio of water to hydrocarbons is discussed. The result shows the ratio was within the range of 1.125-1.286 and the lower the ratio, the more gaseous hydrocarbons were obtained. Moreover, a linear equation between the weight percentage of C5＋ hydrocarbons and the weight ratio of C5＋ hydrocarbons to the total water is established. These results are validated by corresponding experiments. The weight percentage of C5＋ hydrocarbons could be immediately calculated by this linear equation without detailed gas chromatography （GC） analysis of them.

分子筛改性Co／SiO2催化剂对Fischer-Tropsch合成汽油类烃的影响

在中孔SiO2中添加USY，HZSM-5，β分子筛组成双功能载体，并采用初湿浸渍法在载体上浸渍钴盐，制备了一系列分子筛改性的Co／SiO2催化剂，考察了分子筛的类型、HZSM-5分子筛的骨架硅铝比、HZSM-5分子筛在载体中的含量对Fischer-Tropsch合成汽油类烃（C5-12）的影响。实验结果表明，载体中SiO2和分子筛共同作用，提高了催化剂的活性，并使产物分布向汽油类烃偏移，其中，以HZSM-5分子筛改性的Co／SiO2催化剂的催化性能最好。HZSM-5分子筛改性催化剂对催化性能的影响受其骨架硅铝比的影响。当骨架硅铝比n（SiO2）：n（Al2O3）=38、HZSM-5分子筛在载体中的质量分数为20％时，CO转化率达到80％以上，汽油类烃的选择性高达55％，其中异构烷烃的选择性在10％以上。