Highly efficient conversion of methane to formic acid under mild conditions at ZSM-5-confined Fe-sites

Production of value-added chemicals from oriented methane conversion under mild conditions is of great significance for utilization of the energy resources, which, however, remains a great challenge due to its difficulty in the selective activation of C?H bond. Herein, we report a highly selective and efficient methane conversion to formic acid on atomically dispersed Fe sites confined in the nano-channels of ZSM-5. The turnover frequency for producing C1 liquid oxygenates reaches 84,200 h-1 with a high selectivity of 91% to formic acid at 80 ?C, which outperforms all previously reported catalysts. Electron paramagnetic resonance analysis and density functional theory calculations demonstrate that the ZSM-5-confined Fe-O active centers can facilely dissociate the C?H bonds and catalyze successive oxidation of methane to formic acid via free radical mechanisms under mild conditions. This study opens a new path of engineering the microenvironment of confined Fe sites within nanochannels toward highly selective methane conversion with low energy input.

Automated summary

This study introduces a highly selective and efficient method for methane conversion to formic acid by confining atomically dispersed Fe sites in the nano-channels of ZSM-5. The research demonstrates that the confined Fe-O active centers within ZSM-5 can dissociate C-H bonds and catalyze the oxidation of methane to formic acid via free radical mechanisms under mild conditions. This innovative approach opens up a new path for engineering the microenvironment of confined Fe sites within nanochannels for highly selective methane conversion with low energy input.