Twin Boundaries-Induced Centrosymmetric Breaking of Hollow CaTiO₃ Nanocuboids for Piezocatalytic Hydrogen Evolution

Piezocatalysis, a transformative mechanochemical energy conversion technique, has received considerable attention over the past decade for its role in processes such as hydrogen evolution from water. Despite notable progress in the field, challenges remain, particularly in the areas of limited piezocatalysis efficiency and limited availability of materials requiring a non-centrosymmetric structure. Here, a pioneering contribution is presented by elucidating the piezocatalytic properties of hollow CaTiO₃ nanocuboids, a centrosymmetric material with a nominally nonpolar state. Remarkably, CaTiO₃ nanocuboids exhibit an impressive hydrogen production rate of 3.44 mmol g^-1 h^-1 under ultrasonic vibrations, surpassing the performance of the well-established piezocatalyst BaTiO₃ (2.23 mmol g^-1 h^-1). In contrast, commercial CaTiO₃ nanoparticles do not exhibit piezocatalytic performance. The exceptional performance of hollow CaTiO₃ nanocuboids is attributed to the abundance presence of twin boundaries on the {110} facet within its crystal structure, which can impart significant polarization strength to CaTiO₃. Extending the investigation to other centrosymmetric materials, such as SrZrO₃ and BaZrO₃, the experimental results also demonstrate their commendable properties for piezocatalytic hydrogen production from water. This research underscores the significant potential of centrosymmetric materials in piezocatalysis.