In situ confocal microprobe Raman spectroscopy results showed that O22-, O2- and O2δ- (0 < δ< 1) adspecies formed on the O2 pretreated cerium oxide sample when the temperature was below 423 K. At 1023 K, only ...In situ confocal microprobe Raman spectroscopy results showed that O22-, O2- and O2δ- (0 < δ< 1) adspecies formed on the O2 pretreated cerium oxide sample when the temperature was below 423 K. At 1023 K, only CeO2 F2g peak (at 449 cm-1) and O2- species (at 1159 cm-1) were observed on the surface. The reactivity of methane with the oxygen species was lower than that of ethane with the oxygen species.展开更多
In situ FTIR spectra have been used to characterize surface oxygen and adspccies on 20%SrF2/La2O3 catalyst and for the oxidative coupling of methane (OCM).The O2- sur face superoxide with characteristic vibration fre...In situ FTIR spectra have been used to characterize surface oxygen and adspccies on 20%SrF2/La2O3 catalyst and for the oxidative coupling of methane (OCM).The O2- sur face superoxide with characteristic vibration frequency at 1113-1123 cm-1 was formed on the sample after treatment with H2 at 700℃ following exposure to O2 at temperatures between 650℃ and 25℃,The O2 adspecies could also be detected on the working sample at 65O℃ and might play an important role in 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.展开更多
文摘In situ confocal microprobe Raman spectroscopy results showed that O22-, O2- and O2δ- (0 < δ< 1) adspecies formed on the O2 pretreated cerium oxide sample when the temperature was below 423 K. At 1023 K, only CeO2 F2g peak (at 449 cm-1) and O2- species (at 1159 cm-1) were observed on the surface. The reactivity of methane with the oxygen species was lower than that of ethane with the oxygen species.
文摘In situ FTIR spectra have been used to characterize surface oxygen and adspccies on 20%SrF2/La2O3 catalyst and for the oxidative coupling of methane (OCM).The O2- sur face superoxide with characteristic vibration frequency at 1113-1123 cm-1 was formed on the sample after treatment with H2 at 700℃ following exposure to O2 at temperatures between 650℃ and 25℃,The O2 adspecies could also be detected on the working sample at 65O℃ and might play an important role in 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.
