载体制备方法对Co／TiO2／SiO2催化剂结构及费托合成反应性能的影响

Influence of support preparation methods on structure and catalytic activity of Co/TiO_2/SiO_2 for Fischer-Tropsch synthesis

分别采用浸渍法、沉淀法、醇盐水解法、水解回流法制备TiO2/SiO2复合氧化物,采用等体积浸渍法制备费托合成Co/TiO2/SiO2催化剂。通过XRD、Raman、FT-IR、TPR等表征手段考察载体制备方法对催化剂结构的影响,通过费托合成反应考察载体制备方法对催化剂反应性能的影响。实验结果表明,载体中TiO2的引入,调整了钴与SiO2之间的相互作用,使钴物种实现了适宜的还原度与分散度,进而提高了催化剂的费托合成反应活性,降低了甲烷的选择性并提高了C5+烃的选择性。

TiO2/SiO2 supports were prepared by means of impregnation, precipitation, alkoxide hydrolysis and hydrolysis-reflux. Co/TiO2/SiO2 catalysts were prepared by incipient wetness impregnation method. The effects of support preparation methods on the structure of Co/TiO2/SiO2 catalyst and its catalytic activity for Fischer-Tropsch synthesis firs） were investigated by means of XRD, Raman, FT-IR, TPR and CO hydrogenation. The addition of TiO2 changed the interaction between cobalt and silica support quite well to realize appropriate dispersion and reduction degree of supported cobalt, resulting in the remarkable enhancement of the FTS activity with higher C5^＋ selectivity and lower CH4 selectivity.