Bifunctional photoelectrochemical sensor based on Bi/Bi2S3/BiVO4 for detecting hexavalent chromium and hydrogen peroxide

In this study, a bifunctional photoelectrochemical (PEC) sensor based on Bi/Bi 2 S 3 /BiVO 4 (Bi-BSV) is prepared by one-step hydrothermal method. Firstly, the results from experiments show that the PEC performances of Bi 2 S 3 /BiVO 4 -X (BSV-X, X = m(Bi 2 S 3 )/m(Bi 2 S 3 + BiVO 4 )) are higher than those of Bi 2 S 3 and BiVO 4 , and BSV-15% has the highest PEC performance. To further improve the PEC properties of BSV-15%, metal-Bi was introduced to the synthesis of Y-Bi-BSV-15% (Y represents the amount of glucose added). Moreover, UV–visible diffuse reflectance spectrum (UV–vis DRS) and photoluminescence (PL) demonstrate that 0.3-Bi-BSV-15% has the widest visible light absorption range and strongest photogenerated carriers separation capability among all composites. Based on the above results, the PEC sensor based on the 0.3-Bi-BSV-15% for detecting hexavalent chromium (Cr (VI)) and hydrogen peroxide (H 2 O 2 ) is built. The results exhibit that 0.3-Bi-BSV-15% has a wider detection range of 2–230 µM and a lower detection limit of 0.094 µM for Cr (VI) detection. While for H 2 O 2 detection, the detection range and detection limit are 1–130,000 µM and 0.089 µM, respectively. Therefore, 0.3-Bi-BSV-15% has potential application in Cr (VI) and H 2 O 2 detection. • Bi/Bi 2 S 3 /BiVO 4 composites were synthesized by hydrothermal method. • The ternary composite 0.3-Bi-BSV-15% shows excellent PEC activity. • A Z-Scheme heterojunction PEC sensor based on 0.3-Bi-BSV-15% was constructed for switching detection of Cr (VI) and H 2 O 2 . • The PEC sensor has good stability, selectivity and reproducibility.