CHARACTERIZATION OF CO/SILICA CATALYSTS PREPARED BY A NOVEL NO CALCINATION METHOD

摘要

A novel conversion of cobalt nitrate to cobalt oxide using NO (J.R. A. Sietsma et al., patent applications WO 2008029177 and WO 2007071899) was utilized to prepare silica-supported cobalt research catalysts, in order to test the materials for their sensitivity to Fischer-Tropsch synthesis process parameters. In the current contribution, extensive characterization of air calcined and nitric oxide calcined 15% and 25% cobalt-loaded silica catalysts by TPR, hydrogen chemisorption/pulse reoxidation, EXAFS, and XANES is described. For catalysts activated at a standard condition of 350°C for 10 h in H2, despite a lower percentage of reduction observed with the nitric oxide calcined catalysts, the smaller average metal Co crystallite size more than compensates for this effect, leading to a higher Co surface metal active site density on a per gram catalyst basis. The NO calcined catalysts were found to result in higher CO conversion rates on a per g catalyst basis relative to their air calcined counterparts.