"EFEITO DO ZIRCONIO NAS PROPRIEDADES TEXTURAIS E CATALITICAS DA MAGNETITA”.

A.L. COSTA P., P.S. QUERINO, A. ALBORNOZ, S.G. MARCHETTI Y M.DO CARMO RANGEL.

La Plata, Argentina

Congreso; “XV Congreso Argentino de Catálisis – 4to Congreso de Catálisis del Mercosur”; 2007

CONACA-CINDECA

The effect of zirconium on the textural and catalytic properties of magnetite for the water gas shift reaction (WGSR), an important step in the production of high purely hydrogen, was studied in this work. Samples with different amounts of zirconia (Zr/Fe (molar)= 0.1; 0.2;0.3; 0.4 and 0.5) were prepared from precipitation techniques and characterized by chemical analysis, thermogravimetry, differential thermal analysis, X-ray diffraction, specific surface area measurements, temperature programmed reduction,  X-ray photoelectron spectroscopy and  Mössbauer spectroscopy. The catalysts were evaluated in the WGSR at 1 atm and 370 oC. The zirconium addition led to solids with high amounts of zirconium on the surface where it acted as spacer keeping the particles apart, resulting in an increase of specific surface areas. These solids were made off magnetite and tetragonal zirconia. They were catalytically active in WGSR at high temperature (HTS reaction), but zirconium decreased the intrinsic activity of the catalysts, causing in the conversion of carbon monoxide. Zirconium also stabilized the specific surface areas during reaction and made the magnetite reduction to metallic iron more difficult. This is an attractive feature, since this dopant can preserve the active phase of the catalyst (magnetite) during reaction.