Biosynthesis of rod shaped Gd2O3 on g-C3N4 as nanocomposite for visible light mediated photocatalytic degradation of pollutants and RSM optimization

Abstract

To investigate visible light-driven photocatalytic activity, novel heterogeneous catalysts were constructed employing graphitic carbon nitride (g-C3N4) and gadolinium oxide (Gd2O3). Each catalyst was prepared separately. To begin, melamine was used to synthesize g-C3N4. Gd2O3 was prepared via green synthesis by utilizing Cocos nucifera coir extract as a capping agent. Then the prepared g-C3N4 and Gd2O3 were combined in order to form Gd2O3/g-C3N4 nanocomposite. The sole aim of the fabrication of this nanocomposite is to degrade organic pollutants such as amaranth (AM) and congo red (CR) dye, utilizing visible light. The Gd2O3/g-C3N4 nanocomposite was found to be an efficient catalyst in the degradation of AM and CR dye. The prepared nanocomposite was characterized utilizing various techniques like X-ray diffraction, Fourier transform-infra red (FT-IR), UV–visible diffuse reflectance spectroscopy (UV–Vis DRS) and Photoluminescence emission (PL) spectroscopy. The surface area and the surface charge were examined with the aid of BET analysis and Zeta potential respectively. Scanning electron microscope (SEM) and a Transmission electron microscope (TEM) were used to investigate the synthesized nanocomposite's morphology. In contrast with g-C3N4, Gd2O3 and Gd2O3/g-C3N4 have a larger surface area. The Gd2O3/g-C3N4 nanocomposite's PL emission spectra confirmed the lower electron-hole (e-_h+) pair recombination rate. The Gd2O3/g-C3N4 nanocomposite has proved to be an outstanding catalyst with a degradation efficiency of 95% towards CR. Furthermore, the experiments were optimized using Response surface methodology (RSM). These findings revealed that the dye concentration, pH, and catalyst dosage are important parameters in the photocatalytic degradation process. The high correlation co-efficient for the second order polynomial model demonstrated that the data predicted using RSM was in agreement with the experimental results. This work adds to the understanding of g-C3N4-based rare earth metal oxide nano-photocatalysts for efficient organic pollutant degradation.