Step-scheme CeO2/CaIn2S4 heterostructured photocatalysts for efficient reduction of Cr(VI) under visible light

The fabrication of visible-light-driven heterostructured photocatalysts has been regarded as a promising strategy to enhance the photocatalytic performance. Here, a wet chemical method was adopted to prepare step-scheme CeO2/CaIn2S4 (CCIS) composites. The CeO2 nanoparticles were deposited on the surface of CaIn2S4 (CIS) to form a tight interface, namely, heterojunction, which was confirmed by the multiple characterization methods. The formed heterojunction between CeO2 and CIS was advantageous to promoting the charge carrier separation and migration. The photocatalytic performance of the resulted CCIS composites were evaluated by the Cr(VI) reduction under visible light irradiation. The optimized CCIS-10 sample exhibited the highest photocatalytic Cr (VI) reduction activity with the efficiency of 95% within 105 min. The enhanced photocatalytic activity of CCIS was attributed to the construction of step-scheme heterojunction system, leading to the efficient charge separation and high redox potential. The proposed mechanism for the enhanced photocatalytic performance was fully discussed and confirmed. This work may provide a simple strategy to rationally design efficient photocatalyst for Cr(VI) removal.