High‐Entropy Metal Interstitials Activate TiO2 for Robust Catalytic Oxidation

Abstract Substitution metal doping strategies are crucial for developing catalysts capable of activating O 2 , but the leaching of metal dopants has greatly hindered their potential for extensive oxidation reactions under mild conditions. Here, the study develops an entropy‐increase strategy to synthesize high‐entropy metal (Mg, Ca, Mn, Fe, and Co) interstitial functionalized anatase TiO 2 (HE‐TiO 2 ) nanosheets, demonstrating remarkable degradation efficiency across a wide pH range and exceptional stability in a flow‐by electro‐catalytic reactor. Relative to that of pristine TiO 2 , the intense lattice distortion on the (001) plane, an average lattice expansion of 2% on the (100) plane, and decrease of second shell peak of X‐ray absorption spectra serve as compelling evidence for the formation of metal interstitials in HE‐TiO 2 . Theoretical analysis and in situ synchrotron radiation Fourier transform infrared studies reveal that the electron of metal interstitials can populate the subgap states within the host TiO 2 , enabling a moderate adsorption band for robust and efficient O 2 activation. This study introduces a universal strategy for synthesizing a novel class of high‐entropy materials with integrated metal interstitials in metal oxides, promising to enhance the stability and efficiency of O 2 activation catalysts and broaden their potential applications.