In situ FTIR spectral study of the oxygen adspecies on SrF2/La2O3 catalyst during the oxidative coupling of methane

In situ FTIR spectra have been used to characterize surface oxygen, adspecies on 20%SrF2/La2O3 catalyst used for the oxidative coupling of methane (OCM). The Q(2)(-) surface superoxide with characteristic vibration frequency at 1113-1123 cm(-1) was formed on the sample after treatment with H-2 at 700 degreesC following exposure to O-2 at temperatures between 650 degreesC and 25 degreesC, The Q(2)(-) adspecies could also be detected on the working sample at 650 degreesC and might play an important role in the OCM reaction leading to the production of C2H4 from CH4. These results provide evidence that superoxide ions may be the active oxygen on 20%SrF2/La2O3 catalyst during the oxidative coupling of methane.