Preparation of binary palladium-vanadium supported catalysts from metal acetylacetonates

CLAUDIA NEYERTZ; MARÍA VOLPE

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS

Elsevier Science B.V.

Lugar: Amsterdam; Año: 1998 vol. 136 p. 63 - 69

0927-7757

Pd/g-Al2O3 , VOx/g-Al2O3 and two Pd-VOx/g-Al2O3 catalysts were prepared from Pd(AcAC)2 and V(AcAc)3 . One of the binary samples was obtained by reaction of Pd(AcAc)2 with VOx/g-Al2O3 and the other one by interaction of V(AcAc)3 with Pd/g-Al2O3. Using UV spectroscopy it was observed that the reactions of V(AcAc)3 with both the alumina and the Pd/g-Al2O3 catalysts were similar. On the other hand, the fixation of Pd(AcAc)2 to the alumina was quite different to the interaction of the complex with VOx/g-Al2O3; vanadium in alumina modifies the anchoring of palladium complex to the support. In all cases, the amount of CO2 evolved during the calcination of the catalyst precursors indicated that the metal complexes are fixed to the support by ligand-exchange mechanism. Results of the characterization of samples performed by hydrogen chemisorption and TPR suggested that palladium crystals are closely associated with vanadates in one of the Pd-VOx/g-Al2O3 catalysts. Catalytic results for the NO-CO reaction showed that the selectivity to N2 is higher for this binary sample than for all the other catalysts, this being a modification attributed to the interaction between palladium and vanadium.