Facile one-pot synthesis of novel hierarchical Bi2O3/Bi2S3 nanoflower photocatalyst with intrinsic p-n junction for efficient photocatalytic removals of RhB and Cr(VI).

The construction of heterojunction system can promote the separation and transfer of photogenerated electron-hole pairs, which is conducive to the degradation of sewage. In this paper, heterostructured Bi2O3/Bi2S3 nanoflowers are fabricated by a one-step hydrothermal method. The microstructure and optical absorption properties are studied through the detailed characterization of this heterojunction. The visible light photocatalytic ability of as-prepared Bi2O3/Bi2S3 heterojunctions are investigated by photocatalytic removals of RhB and Cr(VI). The results of photocatalysis indicate that removal efficiencies of RhB and Cr(VI) over Bi2O3/Bi2S3 heterojunction are higher than those of pure Bi2O3 and Bi2S3. The improved photocatalytic performance of the Bi2O3/Bi2S3 heterojunctions could be attributed to a combination of the p-n junction between the p-type Bi2S3 and n-type Bi2O3, and large specific surface areas (46.31 m2 g-1). Moreover, the probable photocatalytic mechanism of composite photocatalysts is explored in detail by active species trapping experiments, N2 adsorption-desorption, the transient photovoltage electrochemical impedance spectroscopy and photoluminescence measurements. This work provides new insights into building of the efficient and novel heterogeneous photocatalysts and other energy-related devices.