Pseudo-Jahn-Teller Effect Breaks the pH Dependence in Two-Electron Oxygen Electroreduction.

The hydrogenation of small molecules (like O 2 and CO 2 ) often exhibits strong activity dependence on pHs because of discrepant proton donor environments. However, some catalysts can show seldom dependence on two-electron oxygen electroreduction, a sustainable route of O 2 hydrogenation to hydrogen peroxide (H 2 O 2 ). In this work, a pH-resistant oxygen electroreduction system arising from the pseudo-Jahn-Teller effect is demonstrated. Thorough operando Raman spectra, local environment analyses and density function theory simulations, the lattice distortion of TiO x F y that introduces the pseudo-Jahn-Teller effect contributing to regulating local pHs at electrode-electrolyte interfaces and the absorption/desorption of key *OOH intermediate is revealed. Consequently, as comparison to 78.6% activity attenuation for common catalyst, the TiO x F y displays minor activity decay (3.2%) in the pH range of 1-13 with remarkable Faradaic efficiencies (93.4-96.4%) and H 2 O 2 yield rates (595-614 mg cm -2  h -1 ) in the current densities of 100-1000 mA cm -2 . Further techno-economics analyses display the H 2 O 2 production cost dependent on pHs, giving the lowest H 2 O 2 price of $0.37 kg -1 . The present finding is expected to provide an additional dimension to pseudo-Jahn-Teller effect that leverages systems beyond traditional conception.