Fabrication and mechanism of a novel direct solid-state Z-scheme photocatalyst CdS/BiOI under visible light

A direct CdS/BiOI Z-scheme heterojunction has been successfully synthesized via a hydrothermal method for the first time. The photocatalytic performances of as-prepared samples were evaluated by rhodamine B degradation under visible light (λ > 420 nm) irradiation. The phase structures, morphologies and optical properties of the obtained samples were investigated by several characterization tools such as XRD, SEM, TEM, HRTEM, STEM, XPS, and UV-vis, photocurrent and PL spectroscopy. The results revealed that the CdS/BiOI Z-scheme heterojunction exhibited much higher photocatalytic activity than pure BiOI and CdS, and the sample of CdS/BiOI-2 showed the best activity among all the heterostructure photocatalysts. In addition, the ESR spectrum indicated that ˙O2− and e− were the main active species for the photocatalytic degradation of RhB in our experiment.