Boosting the piezocatalytic performance of BaTiO3-based materials via phase boundary and defect co-engineering

Recently, piezocatalytic technology has been recognized as an efficient and viable strategy for the remediation of aquatic environments. Herein, a synergistic strategy of phase boundary and defect co-engineering has been proposed to enhance the piezocatalytic performance of BaTiO ₃-based ceramic materials: a ceramic system material ((1- x)BaTiO ₃- x(Ca _0.9Sr _0.1)(Sn _0.5Hf _0.5)O ₃, (1- x)BT- xCSSH) was constructed to achieve the coexistence of multiple ferroelectric phases by co-doping ions in the A/B-sites, and defect engineering was realized by a high-temperature annealing. The 0.95BT-0.05CSSH ceramic exhibits the coexistence of rhombic ( R), orthorhombic ( O), and tetragonal ( T) phases, with multiple spontaneous polarization directions and low polarization rotational energy barriers, thereby demonstrating high piezoelectricity ( d ₃₃ = 450 pC/N) and thus outstanding piezocatalytic performance. The degradation rate/reaction rate constant of the 0.95BT-0.05CSSH ceramic material for rhodamine B (RhB) is 71.35 %/13.5 × 10 ⁻³ min ⁻¹. After undergoing a high-temperature annealing, the catalytic activity of the 0.95BT-0.05CSSH ceramic is further improved, resulting in a degradation rate/reaction rate constant of 92.84 %/28.5 × 10 ⁻³ min ⁻¹ for rhodamine B (RhB). The catalytic activity of the 0.95BT-0.05CSSH material is enhanced by the generation of abundant oxygen vacancies during high-temperature annealing, which facilitates the separation and migration of electron-hole pairs. In this study, we propose a novel strategy to upgrade the piezocatalytic performance of BaTiO ₃-based piezoelectric materials, which is useful for the remediation of aquatic environments.