Ternary photocatalysts based on MOF-derived TiO2 co-decorated with ZnIn2S4 nanosheets and CdS nanoparticles for effective visible light degradation of organic pollutants

Abstract

One of the feasible strategies to enhance the photocatalytic properties of TiO₂ is to broaden the visible light response range and accelerate the separation rate of photo-induced electron–hole (e⁻–h⁺) pairs by designing and synthesizing heterostructures using narrow-band-gap semiconductors. In this study, a ternary heterostructure based on MOF-derived TiO₂ was first fabricated via the self-sacrificing template method followed by a two-step chemical bath process. The as-obtained CdS/ZnIn₂S₄/TiO₂ ternary heterostructures exhibited better visible-light photocatalytic properties for the degradation of Rhodamine B (RhB) and tetracycline (TC) than single-component and dual-component systems. Among the ternary heterostructures, it was found that the CdS/ZnIn₂S₄/TiO₂-II showed the highest photoreactivity of 95.3% for RhB removal and 91.8% for TC removal within 40 min. In addition, CdS/ZnIn₂S₄/TiO₂-II could maintain its photocatalytic properties during the stability test. The improvement in photocatalytic properties is attributed to the reasonable construction of a ternary heterostructure, which significantly accelerates the separation and transport of photogenerated e⁻–h⁺ pairs, improves the specific surface area, and broadens the visible light response range. This study demonstrates a promising strategy for developing ternary heterostructures as effective photocatalysts for the degradation of organic pollutants.