Improved photocatalytic degradation and reduction performance of Bi2O3 by the decoration of AuPt alloy nanoparticles

In this work, AuPt alloy nanoparticles were attached onto the surface of Bi2O3 particles to obtain AuPt/Bi2O3 composite. The existence of AuPt bimetallic alloy and their homogeneous distribution on Bi2O3 surface were fully confirmed by XPS characterization and HRTEM observation. The surface plasmon resonance (SPR) effect of noble metals was detected using Ultraviolet–visible diffuse reflectance spectra. The photocatalytic degradation and reduction ability of products were estimated using Acid orange 7 (AO7), phenol and Cr(VI) as the target reactant under simulated sunlight irradiation, indicating that AuPt/Bi2O3 composite possesses remarkable higher photocatalytic activity compared with bare, Au and Pt decorated Bi2O3. In addition, AuPt/Bi2O3 composite is proved to be a stable photocatalysts. The effective separation and migration of photoinduced electrons and holes in AuPt/Bi2O3 sample is demonstrated employing electrochemical and photoluminescence detection. The AuPt/Bi2O3 composite not only has suitable schottky barrier height for trapping the photogenerated charges but also exhibits surface plasmon resonance (SPR) effect, which leads to enhanced photocatalytic activity. •AuPt alloy nanoparticles decorated Bi2O3 was successfully prepared by using a photodeposition route.•AuPt/Bi2O3 composite exhibits obviously enhanced photocatalytic activity compared with Bi2O3.•The mechanism for enhanced photocatalytic activity of AuPt/Bi2O3 composite is discussed.