Iron antimony oxide catalysts for the ammoxidation of propene to acrylonitrile: comments on the method of preparation of tellurium promoted catalysts Original Research Article

Three methods of catalyst preparation for tellurium promoted iron antimony oxide catalysts are investigated: (a) co-precipitation, (b) impregnation and (c) reaction of solid oxides. For all three methods, the addition of Te increases the selectivity for acrylonitrile significantly. For catalysts prepared by co-precipitation, this effect is only apparent at low Te concentrations whereas, for the other two preparation methods, the positive effect on selectivity is maintained at higher doping levels. The catalysts are characterised using X-ray diffraction and X-ray photoelectron spectroscopy. For the Fe30Sb60Te2Ox formulations prepared using the three methods, a similar Te/Sb surface atomic ratio was observed which is consistent with the similar specific activity observed with all three catalysts, indicating that the three methods of preparation can prepare similar surfaces following calcination and catalyst testing. However, the co-precipitation method gives catalyst surface areas approximately three times higher than the other two methods and, consequently, gives the best catalyst performance.