In situ fabrication of ultrathin-g-C3N4/AgI heterojunctions with improved catalytic performance for photodegrading rhodamine B solution

Heterojunction photocatalysts with controllable compositions and textures have attracted extensive research interest in environmental pollutants degradation owing to the superior catalytic activity compared to their single component counterparts. Herein, a series of ultrathin-g-C3N4/AgI heterojunctions (UCNA) were prepared by ultrasonication-assisted liquid exfoliation of bulk g-C3N4 followed by characteristic inner-sphere surface complexation of Ag (I) and in-situ growth of AgI on ultrathin g-C3N4 nanosheets. The structural features and optical properties of all the prepared samples were investigated using X-ray powder diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffused reflectance spectroscopy (UV-vis DRS) and photoluminescence spectroscopy (PL) prior performing photocatalytic activity. The as -prepared heterojunctions showed significant improvement in photocatalytic activity in comparison with pure AgI and g-C3N4 nanosheets with the complete degradation of rhodamine B (RhB) in 60 min at UCNA-70% sample under visible light irradiation with good recycling characteristics. The superior photocatalytic performance of the heterojunctions can be attributed to the combined effects of tightly coupled high-quality interface, appropriate energy band structure and position, along with the increased charge separation and migration efficiency. Based on the analysis of interfacial charge-transfer process across the ultrathin-g-C3N4/AgI heterojunction, a plausible photocatalytic mechanism of ultrathin-g-C3N4/AgI composites was presented.

Automated summary

In this study, a series of ultrathin g-C3N4/AgI heterojunctions were prepared and displayed superior photocatalytic activity in degrading rhodamine B, attributed to the high-quality interface, appropriate energy band structure, and improved charge separation efficiency.