Catalyst Fast Activation: A New Procedure to Prepare Zeolite-Supported Metals

CARLOS M. N. YOSHIOKA1, TERESITA GARETTO2, YVES MANIETTE3, MAURA JORDÃO4, DILSON CARDOSO1,*

CATALYSIS TODAY

Año: 2006

0920-5861

Abstract Bifunctional catalysts containing Pt-Ni/HUSY with 130 mmol Me/g metal content were been prepared by competitive ionic exchange, using complexes [Ni(NH3)6]Cl2 and [Pt(NH3)4]Cl2 solutions. These catalysts were reduced with "fast activation" and "traditional activation" methods. They were characterized by temperature programmed reduction (TPR), hydrogen chemisorption, transmission electronic microscopy (TEM) and subjected to catalytic evaluation for n-hexane isomerization at 250ºC and 1 atm. For TPR results it was observed a larger reduction of Pt2+ and Ni2+ cations when they were reduced at higher temperatures. With hydrogen chemisorption and TEM it was observed that the metallic dispersion is higher for 50Pt50Ni catalyst using the "fast" method and activated at 450ºC, because the synthesizing process is minimized at these conditions. For n-hexane isomerization, by comparing the two activation processes at 500ºC final temperature, the bimetallic Pt-Ni catalyst activated through "fast activation" had slightly higher catalytic activity, with a high gain in total activation time   Keywords: n-hexane, isomerization, Pt-Ni, Hydrogen Chemisorption, TEM.