SrZrO3 Polyhedra with Lattice Variations Showing Efficient Piezocatalytic Hydrogen Evolution

Abstract SrZrO3 cubes with two different sizes as well as octahedra and rhombic dodecahedra have been solvothermally synthesized. Synchrotron X-ray diffraction (XRD) analysis indicates the possession of an orthorhombic crystal structure, with cubes and octahedra having greater cell constant changes. Lattice point images, derived from high-resolution transmission electron microscopy (HR-TEM) images of a single cube and octahedron after fast Fourier transform (FFT) treatment, reveal significant lattice point deviations near the surface region, proving the presence of both bulk and surface lattices. The crystals have ultralarge band gaps in the range of 6.5–7.4 eV. Octahedra exhibit the largest piezoelectric and ferroelectric behaviors among the different particle morphologies. They also deliver the highest piezocatalytic hydrogen evolution rate from pure water, surpassing commercial BaTiO3 powder and many reported materials for piezocatalytic hydrogen generation, demonstrating the value of crystal shape control to enhance piezocatalytic performance.