Combined In-Situ XRD and In-Situ XANES Studies on the Reduction Behavior of a Rhenium Promoted Cobalt Catalyst

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Physical Chemistry Chemical Physics

DOI:https://doi.org/10.1039/c1cp20856j· OSTI ID:1081800

Kumar, Nitin ^[1]; Payzant, E Andrew ^[2]; Jothimurugesan, K ^[3]; Spivey, James J ^[1]

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1. Louisiana State University
2. ORNL
3. Chevron Energy Technology Company

A 10% Co 4% Re/(2% Zr/SiO2) catalyst was prepared by co-impregnation using a silica support modified by 2% Zr. The catalyst was characterized by temperature programmed reduction (TPR), in situ XRD and in situ XANES analysis where it was simultaneously exposed to H2 using a temperature programmed ramp. The results showed the two step reduction of large crystalline Co3O4 with CoO as an intermediate. TPR results showed that the reduction of highly dispersed Co3O4 was facilitated by reduced rhenium by a H2-spillover mechanism. In situ XRD results showed the presence of both, Co-hcp and Co-fcc phases in the reduced catalyst at 400 C. However, the Co-hcp phase was more abundant, which is thought to be the more active phase as compared to the Co-fcc phase for CO hydrogenation. CO hydrogenation at 270 C and 5 bar pressure produces no detectable change in the phases during the time of experiment. In situ XANES results showed a decrease in the metallic cobalt in the presence of H2/CO, which can be attributed due to oxidation of the catalyst by reaction under these conditions.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1081800
• Journal Information: Physical Chemistry Chemical Physics, Journal Name: Physical Chemistry Chemical Physics Journal Issue: 32 Vol. 13; ISSN 1463-9076
• Country of Publication: United States
• Language: English