Microstructure Engineering of Al Doped SrTiO₃/TiO₂ Heterostructure Nanorod Arrays Boosting Piezo‐Photocatalytic Performances

Abstract Modulating the charge‐transfer pathway is of great significance for boosting the photocatalytic efficiency of the catalysts. Herein, well‐ordered Al doping SrTiO₃/TiO₂ heterojunction nanorod arrays (Al‐STO/TiO₂ HNRAs) via a two‐step hydrothermal protocol for efficient piezo‐photocatalysis are reported. The piezoelectric field generated by the internal polarization of Al‐STO/TiO₂ HNRAs can be tailored by Al doping content, which could help to modulate the migration and separation of charge carriers. The doping of Al also makes the charge lifetime from 1.14 ns increased to 1.76 ns. Under the co‐excitation of ultrasonic and ultraviolet irradiation, the oxidation rate constant of Al‐STO/TiO₂ HNRAs can reach 0.037 min⁻¹ for the degradation of Rhodamine B molecules, which was 3.42 times higher than that of the un‐doping sample. The piezo‐potential distribution and charge migration within Al‐STO/TiO₂ HNRAs were explored by piezoelectric force microscopy and COMSOL simulation. This work provides a promising solution toward modulating charge carrier migration for boosting photocatalytic activities with the assistance of mechanic vibration.