Enhanced piezoelectric-induced catalysis of SrTiO₃ nanocrystal with well-defined facets under ultrasonic vibration

Facet engineering of nanocomposite has been confirmed to be an efficient strategy to accelerate their catalytic performances, but to improve their piezoelectric catalytic activities by facet engineering has been seldom reported. Herein, we developed a series of SrTiO₃ nanocrystals with exposed {0 0 1} facet, dominant {1 1 0} facet and co-exposed {0 0 1} and {1 1 0} facets, respectively, and firstly revealed its piezoelectric catalytic performance under ultrasonic vibration. Moreover, the relationship between piezoelectric-induced catalytic activity and facet-dependence of SrTiO₃ nanocrystal was disclosed for the first time. The SrTiO₃ nanocrystal with co-exposed {0 0 1} and {1 1 0} facets exhibited effectively enhanced piezoelectric catalytic activity by degrading Rhodamine B (RhB) under ultrasonic vibration, as compared to that of SrTiO₃ nanocrystals with exposed {0 0 1} facet and dominant {1 1 0} facet, respectively. In addition, trapping experiments and active species quantitative experiments confirmed that the co-exposed {0 0 1} and {1 1 0} facets were beneficial to produce O₂^- and OH with the generation rates of 8.3 and 132.2 μmol g^-1 h^-1, respectively. The OH radical played a dominant role in piezoelectric catalytic process. Finally, the piezoelectric catalysis mechanism of SrTiO₃ surface heterojunction was proposed based on a DFT study. This study presents an in-depth understanding of piezoelectric-induced catalytic of perovskite nanocrystals with exposed well-defined facets.