STUDY ON THE REDUCTION BEHAVIOR OF ZIRCONIA SUPPORTED IRON OXIDE CATALYSTS BY TEMPERATURE-PROGRAMMED REDUCTION COMBINED WITH IN SITU MOSSBAUER SPECTROSCOPY

摘要

The reduction properties of Fe2O3/ZrO2 catalysts with various Fe2O3 loading and the interactions between iron oxide and zirconia have been studied by using temperature-programmed reduction combined with in situ Mossbauer spectroscopy, This is shown that the intermediates formed during reduction depend strongly not only on the reduction temperature but also on the iron loading, Several iron species such as bulk phase alpha-Fe2O3, small alpha-Fe2O3 particles, and surface iron oxide species are found in the zirconia supported iron oxide catalysts, Reduction of the small alpha-Fe2O3 particles is easier than that of the bulk phase alpha-Fe2O3. In contrast, the surface iron oxide species are much more difficult to reduce because of their strong interactions with the support, The phenomena of partial oxidation of Fe2+ cations and Fe3O4 to Fe3+ cations in the reduction processes are observed. (C) 1996 Academic Press, Inc. [References: 22]