Authors: N Fischer M Minnermann M Baeumer E van Steen M Claeys
Publish Date: 2012/05/08
Volume: 142, Issue: 7, Pages: 830-837
Abstract
To obtain nanosized metal and metal salt crystallites with a narrow size distribution synthesis methods utilizing water in oil w/o microemulsions ie reverse micelles have been widely applied and reported in literature In this study we show the effect of support addition at different stages of the reverse micelle based preparation of cobalt oxide on alumina model catalysts All catalysts were characterized with Xray powder diffraction and Raman spectroscopy indicating the presence of Co3O4 on the Al2O3 support Studies of the reduction behaviour and Xray photoelectron spectroscopy however revealed the presence of difficult to reduce cobalt aluminate species in the samples where the support was added during or shortly after the precipitation step in the synthesis process It can therefore be assumed that if the alumina support is added to the reverse micelle solution unprecipitated Co2+ ions and partially dissolved Al3+ combine and form cobalt aluminates In the preparations where the solid cobalt precipitates are recovered from the microemulsion and then supported on the carrier no metalaluminate formation could be observed This study therefore gives important information how metalsupport interaction can be affected during catalyst preparation using reverse micelles
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