Superior photocatalytic performance of Dy2O3/graphitic carbon nitride nanohybrid for the oxidation Rhodamine B dye under visible light irradiation: A superoxide free radicals approach

Abstract

Organic-inorganic hybrid semiconductor nanomaterials have emerged as promising candidates for next-generation energy and environmental solutions. These materials combine organic and inorganic components to form a new class of hybrid nanomaterials with enhanced photocatalytic activity under visible-light irradiation. In this study, g-C3N4 was integrated with different ratios of Dy2O3 using a hydrothermal process. The prepared hybrid composite materials were analysed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), UV–vis diffuse reflectance spectroscopy (UV-DRS), Brunauer-Emmett-Teller (BET) surface area analysis, field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray analysis (EDAX) high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Photoluminescence Spectroscopy (PL) and Electron Paramagnetic Resonance spectroscopy (EPR). The synthesized Dy2O3/g-C3N4 (DYCN) nanohybrid composite has a bandgap energy and surface area of 2.63 eV and 51.8 m2/g respectively. FE-SEM analysis showed nanorods connected to the sheet-like morphology of the prepared DYCN nanohybrid composite material. When exposed to visible light, the organic dye rhodamine B was used as a model pollutant to assess the photocatalytic activity of the synthesized materials. The oxidation of organic molecules was initiated by superoxide (•O2−) free radicals rather than hydroxyl radicals generated during the reaction, which was confirmed by EPR analysis. Due to its narrow bandgap, larger surface area, and presence of f shells in Dy2O3, the synthesized 5 % Dy2O3/g-C3N4 (DYCN 5) nanohybrid composite material showed more visible-light photocatalytic activity than pure g-C3N4 and various ratios of synthesized nanomaterials.