Mechanistic study of CH3OH + O2 photoredox reaction in FeAIP04 sieve by time-resolved FT-IR spectroscopy
- LBNL Library
The mechanism of the ligand-to-metal charge-transfer (LMCT) induced reaction of methanol and O2 at the gas-micropore interface of FeAlPO4-5 sieve has been studied by time-resolved FT-IR spectroscopy. Measurements using the rapid-scan method revealed that the final products, HCO2 Fe and H2O, emerge with a rise time of 4 seconds (250 K) by decomposition of the 2-electron transfer intermediate, HO2CH2OH. Intermediacy of hydroxymethylhydroperoxide was established by direct detection by step-scan FT-IR spectroscopy on the 500 microsecond time scale, and by monitoring of its photodissociation products HCO2H + H2O on the millisecond and second time scale. Formaldehyde was observed as minor 2-electron oxidation product. The fast rise of the HO2CH2OH intermediate strongly suggests that it is formed by direct coupling of HOO and CH2OH radicals. This constitutes the most conclusive evidence yet for the formation of hydroperoxy radical and hydroxymethyl radical as the primary one-electron transfer products of the reaction of CH3OH and O2 at LMCT-excited framework Fe centers.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of Basic Energy Studies. Division of Chemical Sciences (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 795953
- Report Number(s):
- LBNL--47672
- Journal Information:
- Journal of Physical Chemistry A, Journal Name: Journal of Physical Chemistry A Journal Issue: 14 Vol. 106
- Country of Publication:
- United States
- Language:
- English
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