Formation of charge-polarized regions at dual single-atom sites for C-H bond activation in methane

Direct conversion of CH4 into liquid oxygenates under mild conditions is of great significance but remains challenging due to the high dissociation energy of inert C-H bond. Here we report the fabrication of a dual atomic Fe and Pd catalyst with periodic macroporous structure (Fe1-Pd1 OMNC) toward the direct CH4 conversion at room temperature. Mechanism studies reveal that a charge polarization region (Oδ−-Fe-Pdδ+) is formed in-situ on Fe-Pd atomic sites upon oxidant activation, wherein the electron-rich Oδ⁻ and electron-deficient Pdδ+ regions can respectively capture the Hδ⁺ and CH3δ⁻ in CH4 and lead to the activation of C-H bond. As a result, Fe1-Pd1 OMNC demonstrates attractive photothermal catalytic performance toward the selective oxidation of CH4 under Xe lamp irradiation, achieving the productivities of C1 oxygenates as high as 0.754 mmol h−1 and 0.035 mmol h−1 when using H2O2 or O2 as the oxidant, respectively. This work reports a catalyst with atomically dispersed Fe and Pd dual sites for photothermal catalytic CH4 oxidation, and demonstrates that the in-situ formation of charge-polarized regions can induce the polarization and cleavage of C-H bonds.