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

Abstract

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 (O^δ--Fe-Pd^δ+) is formed in-situ on Fe-Pd atomic sites upon oxidant activation, wherein the electron-rich O^δ⁻ and electron-deficient Pd^δ+ regions can respectively capture the H^δ⁺ and CH₃^δ⁻ 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.