“EFEITO DO FERRO NAS PROPRIEDADES DO ÓXIDO DE ZIRCÔNIO SULFATADO”.

A. L. COSTA PEREIRA, S. G. MARCHETTI, A. ALBORNOZ, P. REYES, M. OPORTUS, M. DO CARMO RANGEL SANTOS VARELA

Gramado, Rio Grande do Sul, Brasil,

Simposio; “XX Simposio Iberoamericano de Catálisis”; 2006

Sulfated zirconia has found several industrial applications, mainly for catalyzing reactions which require acidic sites. In order to control the properties of this solid, the effect of iron on the properties of sulfated zirconia was studied in this work. Samples with different iron to zirconia molar ratios were prepared by the sol-gel method, followed by sulfatation and characterized by several methods. It was found that all iron enter the zirconia lattice when Fe/Zr≤0.4, replacing the zirconium ions. However, when higher amounts of iron (Fe/Zr≥0.8) is added, hematite is produced. Different phase can be obtained depending on the iron content and on sulfation. Iron increases the specific surface areas of both sulfated and pure zirconia and also leads to a lower incorporation of sulfate groups as compared to pure zirconia, although it makes the solid thermically more stable. Iron also modifies the sulfated zirconia surface creating moderate acid sites, meaning that it possible to control the acidity of the solid by doping the sulfated zirconia with iron. All these changes are very useful for catalytic applications.