Template Synthesis of Hierarchical Bi2E3 (E ) S, Se, Te) Core-Shell Microspheres and Their Electrochemical and Photoresponsive Properties

Hierarchical, core-shell structured microspheres of bismuth chalcogenides (Bi2E3, E ) S, Se, Te) have been synthesized by chemical transformation of reactive precursor templates, which involves the formation of intermediate BiOCl mircrospheres and their subsequent hydrothermal transformation into Bi2E3 core-shell microspheres. The uniform precursor microspheres consisting of BiOCl nanoplates were obtained by the hydrolysis of BiCl3 under the direction of dextran sulfate. It was proposed that the core-shell structured Bi2E3 microspheres were produced by the chemical transformation of the BiOCl microspheres through the microscale Kirkendall effect. It was found that the obtained core-shell Bi2S3 microspheres could electrochemically charge and discharge with a capacity of 110 mA h g-1 at room temperature. Furthermore, the photoresponsive properties of the hierarchical Bi2S3 core-shell microspheres were investigated, which showed better sensitivity than normal Bi2S3 nanorods, probably owing to multiple reflections of light within the sphere interior voids, indicating their potential applications in photodetectors and photoelectronic switches.