Selective methane oxidation over promoted oxide catalysts. Quarterly report, March 1 - May 31, 1996

Technical Report · Tue Dec 31 04:00:00 EST 1996

DOI:https://doi.org/10.2172/469599· OSTI ID:469599

Klier, K; Herman, R G; Wang, C -B

Series of catalysts consisting of MoO{sub 3}, V{sub 2}O{sub 5}, TiO{sub 2}, and SnO{sub 2} impregnated onto oxide supports consisting of SiO{sub 2} (Cab-O-Sil), TiO{sub 2} or SnO{sub 2} were previously prepared and tested for the selective oxidation of methane to oxygenates, and it was found that the V{sub 2}O{sub 5}/SiO{sub 2} catalyst was the most active and most selective toward the formation of formaldehyde. These catalysts have been characterized by laser Raman spectroscopy after dehydration and during the methane oxidation reaction with a CH{sub 4}/02 = 10/1 reaction mixture at 500{degrees}C in a continuous flow in situ reaction cell. With the V{sub 2}O{sub 5}/SiO{sub 2} catalyst (the most active catalyst among those studied), no significant structural changes were revealed by in situ Raman analyses, indicating that the fully oxidized surface sites were related to the high formaldehyde selectivivity. Over the V{sub 2}O{sub 5}/TiO{sub 2} and V{sub 2}O{sub 5}/SnO{sub 2} catalysts, CO and CO{sub 2} were the principal products produced by oxidation of methane. For the first time, in situ Raman analysis clearly showed that for these latter catalysts, the surface vanadium(V) oxide species were partially reduced under the steady-state reaction conditions. The performance of the V{sub 2}O{sub 5}/TiO{sub 2}/SiO{sub 2} catalyst was similar to that of the V{sub 2}O{sub 5}TiO{sub 2} catalyst, consistent with the earlier observation that vanadia was largely bound to the titania overlayer. It appears that formaldehyde selectivity decreased with increasing catalyst reducibility, but no direct correlation of catalyst activity with reductibility was observed.

• Research Organization: Lehigh Univ., Bethlehem, PA (United States). Zettlemoyer Center for Surface Studies
• Sponsoring Organization: USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
• DOE Contract Number: FG21-92MC29228
• OSTI ID: 469599
• Report Number(s): DOE/MC/29228--5456; ON: DE97051874
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
10 SYNTHETIC FUELS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL PREPARATION
CHEMICAL REACTION YIELD
EXPERIMENTAL DATA
FORMALDEHYDE
METHANE
OXIDATION
PERFORMANCE TESTING
PROGRESS REPORT
RAMAN SPECTRA
SILICA
TIN OXIDES
TITANIUM OXIDES
VANADIUM OXIDES