Metastable Sn‐O‐Pd Sites Modulating the Seesaw Effect Specifically Activate H ₂ O ₂ for the Identification of Plasticizers

Abstract Precisely identifying the plasticizers in the environment is highly desired but often hindered by sluggish reaction kinetics. The generation of hydroxyl radical ( • OH) directly from H 2 O 2 activation offers an ideal pathway to overcome kinetic limitations to achieve plasticizer identification but remains challenging. Herein, a catalyst is reported with a unique electronic interaction by constructing Tin oxide (SnO 2 ) in situ on the Pd metallene (Sn‐O‐Pdene) to efficiently and specifically activate H 2 O 2 to • OH. The Sn‐O‐Pdene exhibits a superior H 2 O 2 activation efficiency with an enhanced • OH selectivity (≈92%). The experiments and density functional theory calculation reveal that the Sn‐O‐Pd sites optimize the adsorption configuration and adsorption energy of O 2 to inhibit the unfavorable turnover of H 2 O 2 caused by O 2 poisoning. In addition, metastable Sn‐O‐Pd sites stretch the HO−OH bond (1.48 Å→1.92 Å) to specifically generate • OH. Accordingly, Sn‐O‐Pdene overcome kinetic limitations of plasticizers to achieve precise identification of five kinds of plasticizers. Furthermore, the Sn‐O‐Pdene catalyst demonstrates exceptional sensitivity in dioctyl phthalate detection, achieving a remarkably low detection limit of 0.5 ng mL⁻¹. This detection capability is significantly more sensitive than the urban sewage discharge standard (8 ng mL⁻¹), highlighting its potential for environmental monitoring applications.