Construction of S-Scheme 2D/2D Crystalline Carbon Nitride/BiOIO3 van der Waals Heterojunction for Boosted Photocatalytic Degradation of Antibiotics

Utilization of semiconductor photocatalyst materials to degrade pollutants for addressing environmental pollution problems has become a research focus in recent years. In this work, a 2D/2D S-scheme crystalline carbon nitride (CCN)/BiOIO3 (BOI) van der Waals heterojunction was successfully constructed for effectively enhancing the degradation efficiency of antibiotic contaminant. The as-synthesized optimal CCN/BOI-3 sample exhibited the highest efficiency of 80% for the photo-degradation of tetracycline (TC, 20 mg/L) after 120 min visible light irradiation, which was significantly higher than that of pure CCN and BOI. The significant improvement in photocatalytic performance is mainly attributed to two aspects: (i) the 2D/2D van der Waals heterojunction can accelerate interface carriers' separation and transfer and afford sufficient active sites; (ii) the S-scheme heterojunction elevated the redox capacity of CCN/BOI, thus providing a driving force for the degradation reaction. The degradation pathways of TC for the CCN/BOI composite were investigated in detail by liquid chromatography-mass spectrometry (LC-MS) analysis. This work provides a design idea for the development of efficient photocatalysts based on the 2D/2D S-scheme van der Waals heterojunctions.

Automated summary

Utilization of semiconductor photocatalyst materials for degrading pollutants has gained significant research attention to address environmental pollution problems. In this study, a 2D/2D S-scheme CCN/BOI van der Waals heterojunction was successfully constructed to enhance the degradation efficiency of antibiotic contaminants. The optimized CCN/BOI-3 sample exhibited a remarkable degradation efficiency of 80% for tetracycline (TC) after 120 minutes of visible light irradiation, outperforming pure CCN and BOI. The enhanced photocatalytic performance can be attributed to the accelerated separation and transfer of carriers at the interface of the 2D/2D van der Waals heterojunction, as well as the elevated redox capacity provided by the S-scheme heterojunction.