Effect of pretreatment conditions on the catalytic performance of Ni-Pt-W supported on amorphous silica-alumina catalysts - Part 1. Catalysts prepared by a sol-gel method

In this work, the catalytic behavior of Pt-Ni-WOx supported on amorphous silica-alumina catalysts, prepared by means of a sol-gel technique was tested by hydroisomerization of n-hexane in a continuous fixed-bed reactor operating at atmospheric pressure. Temperature-programmed desorption of ammonia (TPDA), temperature-programmed reduction, BET and atomic absorption spectroscopy techniques were used to characterize the catalysts. The results revealed that both catalytic activity and surface acidity of these solids is strongly dependent on their calcination and reduction temperatures. Besides, the collected data showed that platinum interacts with tungsten and this interaction depends on the pretreatment conditions. (C) 2007 Elsevier B.V. All rights reserved.