Shape-controlled synthesis and facet-dependent performance of single-crystal Bi25GaO39 photocatalysts

Single-crystal Bi25GaO39 cubes with exposed {100} facets and Bi25GaO39 tetrahedra with exposed {111} and {112} facets were successfully synthesized through a facile hydrothermal route without using any template or organic surfactant for the first time. The formation process studies indicate that the amounts of NaOH and NaGaO2 play an important role in the nucleation and growth rate of Bi25GaO39 crystals. PL spectra and photoelectrochemical measurements indicate that the separation efficiency of photogenerated electron-hole pairs in Bi25GaO39 tetrahedra is higher than that in Bi25GaO39 cubes. Moreover, Bi25GaO39 tetrahedra exhibited superior photocatalytic activity in comparison with Bi25GaO39 cubes for the degradation of AR1 and 4-NP pollutants, which may be primarily ascribed to the differences in exposed facets.