Analysis of novel In2S3/polyimide Z-scheme heterojunctions with enhanced photocatalytic target compound degradation efficiency

In this study, In2S3/PI Z-scheme heterojunctions composite photocatalysts were synthesized via a hydrothermal technique and employed to degrade tetracycline hydrochloride under the action of visible light. The enhancement of their performance was achieved by combining organic and metallic materials. The In2S3/PI heterojunction with 20 wt% In (20In2S3/PI), demonstrated the highest efficiency in target compound (TC) degradation, with a rate of 88%, i.e., 86% and 38% higher than that of PI and In2S3, respectively, over 180 min. This remarkable photocatalytic performance was due to the enhanced charge separation and decreased electron-hole pair recombination, through the formation of a diverse structure. The high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, radical trapping, and electron paramagnetic resonance spectroscopy analyses verified the above speculation. Compared to pure PI and In2S3, the composite photocatalyst exhibited a superior generation of active species, i.e., ∙O2− and h+, along with a higher capacity for mineralization. Furthermore, high-performance liquid chromatography–mass spectrometry analysis was performed to examine the possible pathways for the photocatalytic degradation of TC by the In2S3/PI composites. The findings of this study provide a novel approach to TC degradation.