Construction of Co9S8/Cd0.5Zn0.5S heterojunction photocatalysts with highly efficient photocatalytic activity

Abstract

Photocatalysis has been extensively applied in organic pollutant degradation, and the key focus is on developing efficient and sustainable photocatalysts nowadays. In this work, Co₉S₈/Cd_0.5Zn_0.5S (CS/CZS) heterojunction photocatalysts were prepared by the hydrothermal method, and their photocatalytic activity was evaluated by the degradation of rhodamine B (RhB) under visible-light irradiation. Compared with pristine Co₉S₈ and Cd_0.5Zn_0.5S, CS/CZS heterojunction materials demonstrated better photocatalytic activity. The optimized CS/CZS-2 sample achieved 94% degradation efficiency of RhB under visible-light irradiation within 18 min. Active species trapping experiments revealed that ·O₂⁻ and h⁺ were the main active substances in the photocatalytic degradation process of RhB. The excellent photocatalytic degradation performance can be attributed to the formation of type-II heterojunction between Co₉S₈ and Cd_0.5Zn_0.5S with intimate contact interface, which is conducive to the separation and migration of photogenerated carriers. This study introduces a promising strategy for the design and development of type-II heterojunction photocatalysts specifically aimed at wastewater purification.