Evoking piezo-catalytic activity in SrTiO3 perovskite via lattice strain

Abstract

Piezo-catalysis is a potent environmental remediation method that converts mechanical vibrations into chemical activity, offering advantages in terms of economy and sustainability. However, the non-polar nature of many materials due to their centrosymmetric structure limits the application in piezo-catalysis. In this work, piezo-catalytic activity is effectively evoked by creating oxygen vacancies through various atmosphere heat treatments in the SrTiO₃ (STO) centrosymmetric perovskite. A high piezo-catalytic performance of STO-H (annealing in a hydrogen atmosphere) for H₂O₂ production was observed with an evolution rate of 240.08 μmol g⁻¹ h⁻¹, which is 1.77 times higher than that of STO-N (nitrogen atmosphere) and 2.52 times higher than that of STO-A (air atmosphere). The introduction of oxygen vacancies can generate lattice strain and break the symmetry of the crystal structure, successfully obtaining and enhancing the piezoelectric and piezo-catalytic activity. Narrower energy bandwidths, longer electron lifetimes, and better charge separation and transport characteristics are induced in the annealed STO perovskites. Additionally, theoretical calculations demonstrate that the introduction of oxygen vacancies significantly enhances the adsorption of O₂ molecules on the catalyst surface, which facilitates the conversion of ˙O₂⁻ radicals and further improves the piezo-catalytic performance. This work provides an unsophisticated strategy for realizing piezoelectricity and improving the piezo-catalytic performances of centrosymmetric materials.