Preparation of miscible CdS and homojunction C3N4 hybrids for efficient photocatalytic degradation of tetracycline

Abstract

Aiming at the intrinsic drawbacks of low separation efficiency and high recombination rate of the photogenerated electron–hole pairs, we demonstrate an ingenious design and construction of a hierarchical m-CdS/HCN hetero–homo-structured catalyst by an ultrasonic-mechanical stirring method for TC degradation under visible light irradiation. m-CdS is synthesized by a hydrothermal treatment and ultrasonically smashed into cypress leaf-like nanoparticles. Then, the m-CdS nanoparticles are ultrasonically jolted into the HCN nanosheet slits to form a hierarchical m-CdS/HCN hetero–homo-structure. The unique architecture facilitates the separation and transfer, and suppresses the recombination of the photogenerated carriers, which offers a large surface area, exposing numerous active sites for surface reaction. Benefiting from the unique structural and compositional advantages, the optimized m-CdS/HCN-55 photocatalyst exhibits remarkable performance with a degradation efficiency of 98.2% in 20 min for TC and 92.7% in 30 min for MO, and high stability. Finally, a double-oxidation-site mechanism of h⁺ and ˙O₂⁻ is proposed and discussed in detail.