Effective charge separation in CdS@PANI heterostructure for ultrafast visible light-driven photocatalytic reduction of uranium(VI)

Abstract

The efficient treatment of uranium-containing wastewater provides guarantee for sustainable development of nuclear energy. In this work, a heterogeneous interface structure for photocatalytic reduction of U(VI) was proposed by in-situ decoration of cadmium sulfide (CdS) nanoparticles on polyaniline (PANI) nanorods. The strong coupling between CdS and PANI precisely modulated the interface electronic structure, which promoted the photogenerated charge separation. Multiple spectroscopic characterizations revealed that the interfacial charge polarization with the electrons gathering at the CdS surface and the holes gathering at the PANI, facilitating the performance of photocatalytic reduction of U(VI) under visible light irradiation. The optimal CdS@PANI-10 shows ultrafast U(VI) reduction with efficiency of over 96 % in 5 min. Moreover, the photocatalytic reduction of U(VI) over CdS@PANI-10 can also be activated by direct natural sunlight irradiation. The improvement of catalytic activity of CdS@PANI nanocomposite is due to faster charge separation and migration at the interface between CdS and PANI, as well as the formation of Type-II heterojunction, which was also beneficial for suppressing the CdS photocorrosion. This work introduces a potential strategy to design advanced photocatalysts with efficient electrons and holes separation toward practical application in uranyl ion conversion.