fig7

Figure 7. Flexoelectricity-enhanced catalytic activity in oxides and thin films. (A) Schematic of photocatalysis, flexocatalysis, and flexo-photocatalysis in centrosymmetric Ag₂MoO₄ under simulated sunlight and ultrasonic vibration. (B) Photocatalytic efficiency for methylene blue degradation under photocatalysis, flexocatalysis, and flexo-photocatalysis. (A and B) Reproduced with permission^[60]. Copyright 2021, Elsevier; (C) Finite-element modeling of the strain distribution generated by ultrasound-induced bubble cavitation in SrTiO₃ nanoparticles. (D) Schematic of reactive oxygen species generation associated with flexoelectric polarization under inhomogeneous strain. (C and D) Reproduced with permission^[61]. Copyright 2022, John Wiley and Sons; (E) Morphology of MnO₂ nanoflowers composed of 2D nanosheets before and after ultrasonication. (F) Illustration of flexoelectric polarization in 2D centrosymmetric MnO₂ under inhomogeneous strain. (G) Band-structure modulation by flexoelectric polarization. (H) Schematic of catalytic reactions under dynamic flexoelectric polarization. (E-H) Reproduced with permission^[62]. Copyright 2023, John Wiley and Sons; (I) Strain gradient engineering in LaFeO₃ thin films grown on LaNiO₃/LaAlO₃ and LaNiO₃/SrTiO₃ substrates. (J) Linear sweep voltammetry of LaFeO₃ heterostructures for the oxygen evolution reaction (OER). (K) Gibbs free-energy calculations for the OER steps. (I-K) Reproduced with permission^[31]. Copyright 2024, AIP Publishing. 2D: Two-dimensional; RHE: reversible hydrogen electrode; LFO: LaFeO₃; LNO: LaNiO₃; LAO: LaAlO₃.