LAUSR

Abstract Photocatalytic degradation of organic pollutants (dyes, drugs, pesticides...) is of high interest. In this study, a unique supramolecular architecture of perylene diimide functionalized graphitic carbon nitride (PCN) was prepared and used as a support for UiO-66 nanoparticles. The organic-inorganic heterojunction (PCN@UiO-66) was employed for the photodegradation of rhodamine B (RhB). The synthesized materials were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Under visible light illumination, PCN@UiO-66 achieved a superior degradation efficiency of ∽99% ± 1%. In comparison, pristine g-C3N4, PCN and UiO-66 exhibited degradation efficiencies of 14% ± 0.5%, 44% ± 1.5% and 62%  ± 1%, respectively. The pH was found to affect the photodegradation process and a pH value of 7 resulted in maximum photodegradation efficiency. As confirmed by UV-vis diffuse reflectance spectroscopy and photoluminescence measurements, the enhanced efficiency can be attributed to the improved visible light absorption, as well as reduction of the charge recombination rate brought by perylene dimiide (PDI) photofunctional groups. Moreover, the π-conjugated structure of g-C3N4 along with proper matching between energy levels of components bring synergistic effect in this photocatalytic system. In addition, the photocatalytic mechanism was investigated using radical scavengers, which suggested superoxide radical (O2−•) to be the main species involved in the RhB degradation. Repeated experimental studies and structural analysis of photocatalyst before and after degradation revealed that the photocatalyst exhibits good stability and reusability. It is noteworthy that after four consecutive runs, 91% ± 1% of the photocatalytic efficiency was still preserved. The findings of this study can be used to design high-performance photocatalysts for environmental remediation.