Synthesis, further characterisation and catalytic activity of iron-substituted zeolite LTL, prepared using tetrahedral oxoanion species

Iron substituted zeolite LTL has been prepared, using tetrahedral potassium ferrate(VI), and characterised using X-ray diffraction, Fourier transform infra-red analysis, thermal analysis, chemical analysis and electron microscopy [K. Latham, C.D. Williams, C.V.A. Duke, Zeolites 17 (1996) 513; C.V.A. Duke, K. Latham, C.D. Williams, Zeolites 15 (1995) 213]. Further characterisation using X-ray photoelectron spectroscopy and magnetic susceptibility, confirmed the presence of iron in predominantly +3 co-ordinated state, and demonstrated the significant effect of trace amounts of occluded haematite within a zeolite matrix, on the overall magnetic moment, through magnetic 'titration'. Catalytic activity of hydrogen-reduced Al-LTL and Fe(Al)-LTL samples is illustrated in the CO:H-2 conversion reaction (Fischer-Tropsch), where remarkable selectivity for C-H bond formation, over C-C, was observed for zeolite LTL with increased replacement of aluminium by iron. (C) 2000 Elsevier Science B.V. All rights reserved.