Efficient piezoelectric catalytic degradation of organic pollutants based on defect engineering of heterovalent Al3+ doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 solid solutions

Abstract

Piezocatalysis drives the degradation of pollutants utilizing the piezoelectric effect of materials through mechanical–electrical energy conversion. In this study, heterovalent Al³⁺ doped (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ compounds (BCZT–Al₂O₃) were designed via defect engineering and synthesized through a conventional solid state reaction method. The intrinsic piezoelectric response of lead-free materials is improved and the piezocatalytic activity is enhanced consequently. The relationship among the crystal structure, defects, electrochemistry and catalytic properties has been systematically discussed. BCZT-0.25 mol% Al₂O₃ can boost the intrinsic piezoelectric response by regulating the oxygen vacancies in the material matrix through donor and/or acceptor doping. The degradation rate of the Rhodamine B dye in 70 min by using the polarized 0.25 mol% Al₂O₃-doped BCZT specimens reaches 84.2%. The improvement in piezocatalytic activity is further determined by electrochemical analysis and thermally stimulated depolarization current (TSDC), and the rational explanation is put forth regarding the mechanism of piezoelectric polarization-induced charge transfer. This research offers a promising approach for enhancing piezocatalytic properties through defect engineering, with the potential to expand the scope of applications for lead-free ferroelectric materials, particularly in the treatment of pollutants.