High-performance 0D-2D S-scheme CdS-Bi2WO6 heterostructure for bifunctional photoelectrochemical detection and degradation of chlorpyrifos under visible light irradiation

A bifunctional 0D-2D nanostructured S-scheme CdS-Bi 2 WO 6 heterojunction for highly efficient photoelectrochemical (PEC) detection coupled with the degradation of chlorpyrifos (CP) was prepared by hydrothermal growth of CdS quantum dots onto Bi 2 WO 6 nanosheets. It was uncovered that the so-obtained heterojunction composites notably minimized the recombination of photoinduced electron-hole pairs and exhibited much improved PEC responses compared to pristine Bi 2 WO 6 because of the in-situ formed internal electrostatic field between CdS and Bi 2 WO 6 components induced by the S-scheme heterostructure. After the addition of CP, the interactions between Bi sites and the P=S/C=N groups of CP specifically inhibited the photocurrent signals of obtained CdS-Bi 2 WO 6 sample, impeding the separation and transfer of photoinduced carriers. Significantly, it was found that the photo-generated holes in Bi 2 WO 6 and • OH radicals produced within the PEC system could effectively interact with CP molecule, enabling simultaneous catalytic degradation during detection process and the possible intermediates and degradation pathways of CP were explored and speculated. As a result, a bifunctional PEC platform was introduced for the sensitive and efficient detection and degradation of CP. This platform holds potential to offer theoretical support for the monitoring and remediation of other organophosphate pesticides like CP.