Probing the intermediates in the MO+CH4 <-> M+CH3OH reactions by matrix isolation infrared spectroscopy

摘要

In this review, we present our recent studies on the MO + CH4 and M + CH3OH model reactions (M = transition metals) in order to provide quantitative information regarding the mechanisms for the catalytic methane-to-methanol conversion process. The reaction intermediates were trapped and probed by matrix isolation infrared absorption spectroscopy. Various important intermediates including OM(CH4), M(CH3OH), CH3MOH, CH3M(O)H and CH3OMH are identified via isotopic substitution experiments in the MO+CH(4)and M + CH3OH reactions for selected early and late transition metals. Based on the observed reaction intermediates, some unprecedented reaction pathways are proposed. Complementary quantum chemical calculations support the intermediate identification and help to gain insight into the reaction mechanisms and periodic trends.