Elementary processes in the catalytic combustion of methane (mechanism, intermediates, and controlling reactions). Annual report, October 1983-September 1984

Technical Report · Wed Apr 03 04:00:00 EST 1985

OSTI ID:5704109

Quinlan, M; Wise, H

The surface reactions involved in the catalytic oxidation of methane were investigated using single-crystal metal surfaces, supported metal catalysts, and binary-metal-oxide catalysts. For Ni(111) the rate of reaction of surface-adsorbed oxygen (at fractional monolayer coverage) with gaseous methane is greatly reduced in the presence of coadsorbed sulfur. The oxidative removal of sulfur adatoms requires elevated temperatures (> 600 K). Also, the formation of an oxide layer overgrowth can occur on top of the sulfur adlayer. During methane oxidation (O/sub 2//CH/sub 4/ > 2) catalyzed at elevated temperatures (> 600 K) by dispersed metals (Ir, Pt) on an alumina support, the introduction of H/sub 2/S (at < 1 ppm) into the feed stream was found to have a negligible effect. Presumably the sulfur species is converted to SO/sub 2/, thereby preventing a sulfur buildup on the metal surface. Experimental studies of surface intermediates by electron energy loss spectroscopy revealed the formation of a hydroformyl radical (OCH/sub 2/) formed by reaction of gaseous methane with preadsorbed oxygen (initial surface coverage less than 0.5 monolayer). Also, its presence was deduced from temperature-programmed desorption studies leading to the simultaneous formation of CO and H/sub 2/ in equimolar amounts.

• Research Organization: SRI International, Menlo Park, CA (USA)
• OSTI ID: 5704109
• Report Number(s): PB-85-188357/XAB
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030400* -- Natural Gas-- Products &amp; By-Products
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800 -- Combustion
Pyrolysis
&amp; High-Temperature Chemistry
ALKANES
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COMBUSTION
ELEMENTS
HYDROCARBONS
KINETICS
METALS
METHANE
ORGANIC COMPOUNDS
OXIDATION
REACTION KINETICS
THERMOCHEMICAL PROCESSES