Unraveling the Influence of Surface Termination, Symmetry, and Layer Thickness on the Piezocatalytic Activity of Tetragonal Barium Titanate

Piezocatalysis can convert mechanical energy to chemical energy. Thus, it has shown great potential in energy and environmental applications. As a widely studied piezocatalyst, barium titanate (BTO) can catalyze water splitting and pollutant degradation under ultrasonic vibration. However, mechanistic insight into the role of surface termination, symmetry, and layer thickness in piezocatalysis has been largely underexplored. In this work, using BTO as an example, we adopted the quantum-continuum-electrochemical (QCE) method to systematically study how these factors determine piezocatalytic activity. Our simulation reveals that TiO 2 -terminated BTO shows a more suitable redox potential window than BaO-terminated BTO in piezocatalysis. Moreover, we also find that symmetric BTO with mild thickness possesses a well-matched redox potential to the experimental voltage window of water splitting, while asymmetric BTO needs an extremely large thickness to reach the same performance. Combining our simulation results with experimental literature, we suggest that symmetric TiO 2 -terminated BTO should be the dominant active moiety in the piezocatalysis of BTO nanoparticles. Our study unravels how the structure of BTO determines piezocatalytic activity, which could benefit further development of piezocatalysts in BTO or other perovskite families.