Fabrication and characterization of In2.77S4/COFs composite photocatalyst for efficient degradation of tetracycline

In2.77S4 nanosheets were first synthesized and then used to construct the In2.77S4/COFs composite photocatalyst by an in situ hydrothermal growth method. The structure, optical properties, morphology, chemical composition and photo-generated carriers behavior of the as-synthesized In2.77S4/COFs composites were discussed, respectively. The tetracycline dilute solution was selected to evaluate its photocatalytic activity. Experimental results show that COFs can improve the photocatalytic activity and recyclability of In2.77S4 under visible light irradiation. With the increase in COFs dosage, the photocatalytic efficiency of the as-synthesized composite samples is first increased and then decreased. When the amount of COFs is 10 wt%, the as-synthesized In2.77S4/COFs composite photocatalyst shows the maximum photocatalytic degradation efficiency of 93.8% in 90 min, which is higher than that of 75.1% of In2.77S4 and 0.1% of COFs, respectively. Furthermore, the separation and migration efficiency of the photo-generated electron-hole pairs of the as-synthesized composite are improved in comparison of the pure samples and the transient photocurrent intensity of In2.77S4/COFs composite is about 2.5 times than that of pure In2.77S4 and 10 times than that of pure COFs. In addition, holes play a major role during the photocatalytic degradation process.