CENTRO DE INVESTIGACION Y DESARROLLO EN CIENCIAS APLICADAS "DR. JORGE J. RONCO"
Unidad Ejecutora - UE
DETERMINATION OF Fe4+ IONS IN PARTIALLY SUBSTITUTED PEROVSKITES La1-XCaXFeO3.
B. P. BARBERO, L. E. CADÚS, S. G. MARCHETTI
Año: 2009 vol. 194 p. 367 - 367
The partial substitution for lanthanum in LaFeO3 perovskite with calcium,a cation with lower oxidation state, causes an electronic unbalance. The X-raydiffraction (XRD) and temperature-programmed reduction (TPR) results suggestthat, consequently, the elevation of the iron oxidation state to Fe(IV) occurs.The Mössbauer spectroscopy studies confirm the onset of Fe(IV) to maintain thestructure electroneutrality. The quantification of Fe(IV) species is in good agreementwith the estimated amount from the hydrogen consumption in the TPR studies. Thisshows that TPRa very simple technique widely used to characterize heterogeneouscatalystsis an appropriate technique to quantify Fe(IV) species in LaFeO3 substitutedperovskites. To verify the correct assignment of step corresponding to theFe(IV) reduction, the different iron species after each reduction step, during the TPRexperiment, were confirmed by Mössbauer spectroscopy in controlled atmosphere.