Strain‐Engineered Nano‐Ferroelectrics for High‐Efficiency Piezocatalytic Overall Water Splitting

Developing nano‐ferroelectric materials with excellent piezoelectric performance for piezocatalysts used in water splitting is highly desired but also challenging, especially with respect to reaching large piezo‐potentials that fully align with required redox levels. Herein, heteroepitaxial strain in BaTiO3 nanoparticles with a designed porous structure is successfully induced by engineering their surface reconstruction to dramatically enhance their piezoelectricity. The strain coherence can be maintained throughout the nanoparticle bulk, resulting in a significant increase of the BaTiO3 tetragonality and thus its piezoelectricity. Benefiting from high piezoelectricity, the as‐synthesized blue‐colored BaTiO3 nanoparticles possess a superb overall water‐splitting activity, with H2 production rates of 159 μmol g−1 h−1, which is almost 130 times higher than that of the pristine BaTiO3 nanoparticles. Thus, this work provides a generic approach for designing highly efficient piezoelectric nanomaterials by strain engineering that can be further extended to various other perovskite oxides, including SrTiO3, thereby enhancing their potential for piezoelectric catalysis. Heteroepitaxial strain in BaTiO3 nanoparticles with a designed porous structure is induced by engineering the surface reconstruction, resulting in a significant increase of the BaTiO3 tetragonality and thus its piezoelectricity. Benefiting from high piezoelectricity, the as‐synthesized BaTiO3 nanoparticles possess a superb piezocatalytic overall water‐splitting activity.