Relevance in the Fischer-Tropsch synthesis of the formation of Fe-O-Ce interactions on iron-cerium mixed oxide systems

被引:59
作者
Perez-Alonso, F. J.
Granados, M. Lopez
Ojeda, M.
Herranz, T.
Rojas, S.
Terreros, P.
Fierro, J. L. G.
Gracia, M.
Gancedo, J. R.
机构
[1] CSIC, Inst Catalisis & Petroleoquim, E-28049 Madrid, Spain
[2] CSIC, Inst Quim Fis Rocasolano, E-28006 Madrid, Spain
关键词
CARBON-SUPPORTED COBALT; ELECTRON-SPECTROSCOPY; CATALYSTS; HYDROGENATION; SELECTIVITY; XPS; CO; FERRIHYDRITE; KINETICS; MONOXIDE;
D O I
10.1021/jp064575f
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
A series of Fe-Ce mixed oxides (95 atom % Fe-5 atom % Ce) has been prepared by different methods: coprecipitation, impregnation, and physical mixture of Ce and Fe oxides. These solids have been tested in the Fischer-Tropsch synthesis. The characterization of the catalytic precursors was carried out by X-ray diffraction (XRD), Raman, Mossbauer, and X-ray photoelectron (XPS) spectroscopic techniques. When the preparation method ensures a microscopic contact between Fe and Ce cations in the solid, several types of Fe-Ce interactions are present in the calcined solids. The interactions take the shape of Fe-O-Ce bridges that can exist either in the hematite-like solid solution or in the interphase between the Fe oxide covered by microcrystals of Ce oxide. In the case of the hematite-like solid solution, Ce(IV) cations are dissolved in the alpha-Fe2O3 network. The promotion by Ce of the catalytic properties observed in the final catalysts can be directly related with the detection of these Fe-O-Ce bridges in the calcined solids. The Ce promotion results in a larger yield to hydrocarbons, a higher production of olefins, and a higher selectivity to medium and large chain hydrocarbons (larger than six carbon atoms). It is proposed that the Ce promotion is due to the presence of Fe-0-Ce(III) ensembles in the final catalysts arising from the initial Fe-O-Ce bridges developed in the parent calcined samples.
引用
收藏
页码:23870 / 23880
页数:11
相关论文
共 47 条
[1]  
[Anonymous], CATALYSIS CERIA RELA
[2]   QUANTITATIVE XPS ANALYSIS OF THE OXIDATION-STATE OF CERIUM IN PT-CEO2/AL2O3 CATALYSTS [J].
BAK, K ;
HILAIRE, L .
APPLIED SURFACE SCIENCE, 1993, 70-1 :191-195
[3]   HYDROGENATION OF CARBON-MONOXIDE ON CARBON-SUPPORTED COBALT RARE-EARTH CATALYSTS [J].
BARRAULT, J ;
GUILLEMINOT, A ;
ACHARD, JC ;
PAULBONCOUR, V ;
PERCHERONGUEGAN, A .
APPLIED CATALYSIS, 1986, 21 (02) :307-312
[4]  
BARRAULT J, 1991, STUD SURF SCI CATAL, V61, P357
[5]  
BERRY FJ, 1978, ADV INORGANIC CHEM R
[6]  
Bersani D, 1999, J RAMAN SPECTROSC, V30, P355, DOI 10.1002/(SICI)1097-4555(199905)30:5<355::AID-JRS398>3.0.CO
[7]  
2-C
[8]   SATELLITE STRUCTURE IN X-RAY PHOTOELECTRON-SPECTRA OF SOME BINARY AND MIXED OXIDES OF LANTHANUM AND CERIUM [J].
BURROUGHS, P ;
HAMNETT, A ;
ORCHARD, AF ;
THORNTON, G .
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1976, (17) :1686-1698
[9]   Formation of cubic phases on heating ferrihydrite [J].
Campbell, AS ;
Schwertmann, U ;
Campbell, PA .
CLAY MINERALS, 1997, 32 (04) :615-622
[10]   Role of tilted CO in dynamics of CO insertion on Ce-Rh/SiO2 [J].
Chuang, SSC ;
Srinivas, G ;
Brundage, MA .
ENERGY & FUELS, 1996, 10 (03) :524-530