(00l)-Facet-Exposed Planelike ABi2Nb2O9 (A = Ca, Sr, Ba) Powders with a Single-Crystal Grain for Enhancement of Photocatalytic Activity

(00l)-facet-exposed planelike ABi2Nb2O9 (A = Ca, Sr, Ba) powders with a single-crystal grain were obtained successfully by the molten salt method. The planelike grains were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy. With modification by platinum nanoparticles as a cocatalyst, these materials were tested as photocatalysts for water splitting under full arc light irradiation. The H2 evolution activities of the planelike ABi2Nb2O9 (A = Ca, Sr, Ba) prepared by the molten salt method were almost an order of magnitude higher than those of the ABi2Nb2O9 (A = Ca, Sr, Ba) prepared by traditional solid-state method. The planelike ABi2Nb2O9 (A = Ca, Sr, Ba) powders also have higher O2 evolution activities than the ABi2Nb2O9 (A = Ca, Sr, Ba) powders prepared by the traditional solid-state method. The oxidation and reduction catalytic sites on the planelike AB...