A Z-scheme 2D/0D ZnIn2S4/ZnO heterostructure for efficient photocatalytic degradation of tetracycline: energy band engineering and morphology modulation

Abstract

Semiconductor-based photocatalysis is of great practical significance to degrade persistent organic pollutants (POPs). However, it still faces challenges and always in pursuit to construct a photocatalyst system with efficient charge separation and strong redox capacity. Herein, a Z-scheme energy band configuration in a hierarchical heterostructure composed of two-dimensional (2D) ZnIn₂S₄ nanosheets and zero-dimensional (0D) ZnO nanoparticles was fabricated for the degradation of tetracycline (TC)—one of the typical POPs. On the one hand, the Z-scheme heterojunction inhibits the recombination of charge carriers and preserves the strong redox capacity of ZnIn₂S₄ and ZnO. On the other hand, the hierarchical microstructure and the 2D/0D subunits endow the ZnIn₂S₄/ZnO photocatalyst with good light harvesting, intimate interface contact, and short charge transfer. As a result, the hybrid photocatalyst exhibited a high reaction rate constant of 0.074 min⁻¹ for TC degradation, which is 5.4 and 2.8 times that of the pure ZnIn₂S₄ and ZnO, respectively. This work provides new insight into the integration of energy band engineering and morphology modulation to design advanced photocatalytic systems for POP treatment.