A light-driven photoelectrochemical sensor for highly selective detection of hydroquinone based on type-II heterojunction formed by carbon nanotubes immobilized in 3D honeycomb CdS/SnS2

The ecological environment and public safety are seriously threatened by the typical phenolic contaminant hydroquinone (HQ). Here, using a straightforward physical mixing technique, we created an n - n heterojunction by uniformly immobilizing cadmium sulfide (CdS) nanoparticles on the surface of a three-dimensionally layered, flower-like structure made of tin sulfide (SnS 2 ). Then, as photosensitizers , carbon nanotubes (CNTs) were added to the CdS/SnS 2 complex to create a type-II heterostructure of CdS/SnS 2 /CNTs with synergistic effects. Subsequently, the detector HQ was bound to the modified photoelectrodes , which was accompanied by the hole oxidation of the bound HQ, leading to a significant increase in the photocurrent signal, thus allowing specific and sensitive detection of HQ. Under optimized detection conditions, the proposed photoelectrochemical sensor shows a wide detection range of 0.2 to 100 μM for HQ with a detection limit as low as 0.1 μM. The high accuracy of the sensor was demonstrated by comparison with the detection results of UV–vis spectrophotometry . In addition, the photoelectrochemical sensor exhibits good reproducibility, stability, selectivity , and specificity, providing a light-driven method to detect HQ.