The role of Rh on a substituted Al Anderson heteropolymolybdate:

CABELLO, CARMEN I.; MUÑOZ, MERCEDES; BOTTO, IRMA L.; PAYEN, EDMOND

THERMOCHIMICA ACTA

Elsevier

Año: 2006 vol. 447 p. 22 - 29

0040-6031

The influence of Rh heteroatom on the molybdenum reducibility in the Anderson type heteropolyoxomolybdate structure of formula (NH4)3[RhMo6O24H6].7H2O was investigated  by means of TPR technique. With comparative purposes, the thermal behavior in non reducing conditions was also carried out by means of TGA-DTA studies. The study was performed by  XRD, SEM, EDAX and FTIR-Raman techniques. Results were related to those preliminary measurements over other XMo6 Anderson phases. Likewise, Rh(III)-Al(III) formal replacement in the RhMo6 structural arrangement was proved. The formation of a solid solution in a limited range of composition (up to 0.25 Rh) was established in order to explore the catalytic performance of  g-Al2O3 supported planar heteropolyoxomolybdate, aiming at optimizing the noble metal content in the catalytic system. Preliminary measurements of RhMo6/g-Al2O3 and (Rh,Al)Mo6/g-Al2O3 activity for HDS and HYD processes were also performed. These results were compared to those obtained for CoMo6/g-Al2O3 system in similar operating conditions and other conventional catalytic systems. The potentiality and scope of  RhMo6 catalytic system for  the HDS and HYD processes were analyzed.