Radical Negative‐Feedback in High Entropy UiO‐67 to Break the Activity–Stability Trade‐Off in Photocatalytic Oxygenation of CH ₄

ABSTRACT

The activity–stability trade‐off has long been a Gordian knot for metal–organic frameworks (MOFs) photocatalyst. Here, a high‐entropy UiO‐67 MOF (HE‐UiO‐67) constructed with 2,2'‐bipyridine‐5,5'‐dicarboxylic acid as the linker and ZrCeHfSnFe metal nodes was designed to induce a hydroxyl radical (•OH) negative‐feedback mechanism to disentangle the trade‐off in methane oxygenation with H ₂ O ₂ . When the •OH concentration generated at Fe sites exceeds the tolerance threshold of adjacent Ce─O bonds, the Ce centers are reconstructed by ligand abstraction into the unsaturated Ce sites for driving the interfacial H ₂ O ₂ conversion into low oxidative O ₂ or •OOH species in high‐entropy metal nodes, thereby blocking the MOFs damage. This unique radical negative feedback process in HE‐UiO‐67 can maximize the concentration of radicals while maintain the stable operation for over 100 h in an ambient pressure flow‐phase system, substantially exceeding most of the previous reports. Under visible light irradiation, HE‐UiO‐67 photocatalyst exhibits an outstanding liquid oxygenate yield of up to 9732 µmol g ⁻¹ h ⁻¹ with a selectivity of 93.5%. Overall, this study opens up a promising strategy for designing efficient and durable photocatalysts to break the activity–stability trade‐off in CH ₄ oxygenation.