Salt-induced anisotropic SrTiO3 to boost piezo-photocatalytic processes

Piezo-photocatalysis materials that can combine the piezoelectric effect in photocatalytic processes are very attractive for promising applications in water splitting and contaminant degradation. The perovskite oxides with adjustable exposed crystal facets are expected to optimize the catalysis activities by exposing the high-energy planes. In this work, we develop a salt-assisted strategy that controllably prepares anisotropic SrTiO₃ particles with a large number of surface defects, which exhibit good piezo-photocatalytic features. The exposure of the crystal facets can be tuned by changing the assistants (NaCl or SrCl₂). The SrCl₂ can lead to the exposure of the (110) plane in one-dimensional SrTiO₃ particles and NaCl can induce the cubic SrTiO₃ particles with the exposure plane of (200). Attributed to the exposed high-energy facets and abundant oxygen vacancies, the latter show higher activities than the former in both water splitting and dye degradation under light irradiation and ultrasonic vibration. Our work provides an approach to optimize piezo-photocatalytic activities by tuning the exposed crystal facets.