Active Fischer-Tropsch synthesis Fe-Cu-K/SiO_2 catalysts prepared by autocombustion method without a reduction step

作     者：Suthasinee Pengnarapat Peipei Ai Prasert Reubroycharoen Tharapong Vitidsant Yoshiharu Yoneyama Noritatsu Tsubaki 

作者机构：Program in PetrochemistryFaculty of ScienceChulalongkorn University Department of Applied ChemistrySchool of EngineeringUniversity of Toyama Department of Chemical TechnologyFaculty of ScienceChulalongkorn University 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2018年第27卷第2期

页      面：432-438页

核心收录：

学科分类：081702[工学-化学工艺] 081705[工学-工业催化] 08[工学] 0817[工学-化学工程与技术] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：financial support to the Overseas Academic Presentation Scholarship for Graduate Students  Graduate School  Chulalongkorn University 

主　　题：Fischer-Tropsch synthesis Iron-based catalysts Autocombustion Iron carbide SiO2 

摘      要：The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis（FTS） without a reduction step. The effect of different citric acid（CA）：iron nitrate（N） molar ratios and acid types on the FTS performance of catalysts were investigated. The CA：N molar ratios had an important influence on the formation of iron active phases and FTS activity. The iron carbide（FexC）, which is known to be one of the iron active phases, was demonstrated by the X-ray diffraction and X-ray photoelectron spectroscopy. Increasing the CA：N molar ratios up to 0.1 increased CO conversion of catalyst to 86.5%, which was then decreased markedly at higher CA：N molar ratios. An excess of CA resulted in carbon residues covering the catalyst surface and declined FTS activity. The optimal catalyst（CA：N molar ratio = 0.1） achieved the highest CO conversion when compared with other autocombustion catalysts as well as reference catalyst prepared by impregnation method, followed by a reduction step. The autocombustion method had the advantage to synthesize more efficient catalysts without a reduction step. More interestingly, iron-based FTS catalysts need induction duration at the initial stage of FTS reaction even after reduction, because metallic iron species need time to be transformed to FexC. But here, even if without reduction, FexC was formed directly by autocombustion and induction period was eliminated during FTS reaction.