Visible-light-active CdS/PANI heterojunctions: Synergistic charge separation and enhanced photostability for efficient photocatalytic degradation

CdS@PANI Type II heterojunction inhibits CdS photo-corrosion for enhanced stability. • Interfacial electric field boosts charge separation and photocatalytic performance. • The degradation rate constant of CdS@PANI-5% for RhB is 2.34 times. • Interpreted the charge transfer and degradation mechanisms of CdS@PANI. This study synthesized a CdS@polyaniline (PANI)−5% type-II heterojunction photocatalyst (containing 5% polyaniline) for the efficient degradation of organic matter in water. As demonstrated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses of CdS@PANI-5%, the PANI nanofibers inhibit CdS aggregation and increase the number of reactive active sites. X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and density functional theory calculations show that interface electrons are reconstructed at the interface, reducing the carrier escape barrier and effectively separating the CdS-photogenerated charge carriers. The results are confirmed by photoluminescence and electrochemical impedance spectroscopies. In a rhodamine B (RhB) degradation experiment, CdS@PANI-5% achieves a 2.34 higher RhB degradation rate constant than pure CdS and maintained high activity (>84%) after four cycles. These results confirm the photocatalytic degradation performance and structural stability of CdS@PANI-5%. Finally, the degradation mechanism of CdS@PANI was derived through electron paramagnetic resonance and liquid chromatography–mass spectrometry. Download: Download high-res image (201KB) Download: Download full-size image