Environmentally benign synthesis of branched Bi2O3–Bi2S3 photocatalysts by an etching and re-growth method

Abstract

Synthesizing heterostructured nanomaterials of controllable morphologies by an environmentally benign method is an area of frontier research. In the present work, Bi₂O₃ microtubes and branched Bi₂O₃–Bi₂S₃ composites were synthesized by a simple hydrothermal method without the need for using toxic substances as surfactants (templates) or solvents. Single-crystalline Bi₂S₃ nanorods and nanosheets are controllably grown on the surface of Bi₂O₃ microtubes. We propose an “etching and re-growth” mechanism for the generation of the Bi₂O₃–Bi₂S₃ composites. Owing to the presence of Bi₂S₃ and the branched structure, there is great improvement of visible-light absorption ability, and due to the formation of Bi₂O₃–Bi₂S₃ heterojunctions, there is facile separation of photogenerated charge carriers. It is observed that the as-prepared composites show an enhanced photocurrent response and improved photocatalytic activity under visible-light illumination.