In situ construction of a direct Z-scheme CdIn2S4/TiO2 heterojunction for improving photocatalytic properties

Abstract

Direct Z-scheme photocatalytic systems driven by visible light to eliminate organic pollutants in wastewater have become important scientific tools in the field of photocatalysis. In this study, a direct Z-scheme CdIn₂S₄/TiO₂ heterojunction with high efficiency was prepared through a simple hydrothermal method. Benefiting from the increased visible light response and prolonged lifetime of photoexcited carriers, the as-prepared CdIn₂S₄/TiO₂ composites exhibit significantly promoted photocatalytic performance for the degradation of methyl orange (MO) under visible-light illumination (λ ≥ 420 nm). The CdIn₂S₄-25 wt% TiO₂ (25CT) photocatalyst exhibited the highest degradation efficiency (96.2% within 30 min) with a rate constant of 0.1193 min⁻¹ and remarkable stability and repeatability. In the meantime, the study of the photocatalytic mechanism shows that the charge transfer path conforms to the Z-scheme model, in which h⁺ and ˙O₂⁻ are the main active species. This study provides strong practical support for the preparation of efficient Z-scheme photocatalytic materials by hydrothermal methods.