In-situ fabrication of manganese ferrite grafted polyaniline nanocomposite: A magnetically reusable visible light photocatalyst and a robust electrode material for supercapacitor.

Herein, we reported the in-situ preparation of manganese ferrite (MnFe2O4) grafted polyaniline (Pani), a magnetic nanocomposite for the potential visible light photocatalytic material as well as electrode material for supercapacitor. The physical characterization of the prepared nanoparticle and nanocomposite was examined with various spectroscopic and microscopic analyses. The peaks observed in the X-ray diffraction study confirm the face-centered cubic phase of MnFe2O4 nanoparticles with a grain size of ∼17.6 nm. The surface morphology analysis revealed the uniform distribution of spherical-like MnFe2O4 nanoparticles on the surface of Pani. The degradation of malachite green (MG) dye under exposure to visible light was investigated using MnFe2O4/Pani nanocomposite as a photocatalyst. The results exposed the faster degradation of MG dye was accomplished by MnFe2O4/Pani nanocomposite than MnFe2O4 nanoparticles. The energy storage performance of the MnFe2O4/Pani nanocomposite was analyzed through cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy analyses. The results exposed that the MnFe2O4/Pani electrode achieved a capacitance of 287.1 F/g than the MnFe2O4 electrode (94.55 F/g). Further, the respectable capacitance of 96.92% was achieved even after 3000 repetitive cycles stability . Based on the outcomes, the MnFe2O4/Pani nanocomposite can be suggested as a promising material for both photocatalytic and supercapacitor applications.

Eco-friendly Synthesis of CRGO and CRGO/SnO2 Nanocomposite for Photocatalytic Degradation of Methylene Green Dye.

Reduced graphene oxide (rGO) was synthesized from a simple, cost-effective, and eco-friendly method by using Capsicum annuum (CA) as reducing agent. The rGO was mixed with SnO2 to synthesize a nanocomposite. The synthesized materials were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and UV-visible spectroscopy techniques. The SnO2-C. annuum reduced graphene oxide (CRGO) nanocomposite exhibited a photodegradation efficiency of 97.4% when employed to remove methylene green (MG) dye. The synthesized nanocomposite showed improved photodegradation ability due to its high charge transfer and separation and owing to the presence of the large surface area of the CRGO network system. Degraded water was used in the plant and animal survival study, in which the dye solution treated with CRGO nanocomposite exhibited better growth compared to that of untreated MG solution. Likewise, in the ecotoxicity study, Artemia salina and zebra fish (Danio rerio) survival was found to be enhanced with CRGO nanocomposite-treated dye solution. This finding supports the effectiveness of CRGO/SnO2 nanocomposite for the treatment of MG dye-contaminated effluent samples.

Synthesis of reduced graphene oxide/ZnO nanocomposites using grape fruit extract and Eichhornia crassipes leaf extract and a comparative study of their photocatalytic property in degrading Rhodamine B dye.

In the present work, we report the comparative study of photocatalytic degradation of Rhodamine B (RhB) dye in aqueous solution by using ZnO-graphene nanaocomposites obtained using two different natural reducing agents namely Grape and Eichhornia crassipes. Graphene oxide (GO) was synthesized by Hummer's method followed by reduction of the graphene oxide using natural reducing agents Grape and Eichhornia crassipes. The two samples of graphene oxide (Gr-rGO and Ei-rGO) were treated with ZnO to form a rGO-ZnO nanocomposites. The dye degradation was observed by the decrease in the absorption and decolorization in the presence of visible light. The degradation efficiency was found to be dependent on the concentration of rGO-ZnO nanocomposites added to the dye solution. The Ei-rGO has a higher adsorbing capacity due to its large surface area. A degradation efficiency of 67% was achieved by ZnO alone, whereas with the rGO-ZnO nanocomposite, the photocatalytic degradation efficiency for removal of RhB dye was found to be enhanced. The degradation efficiency was 70.0% and 97.5% with Gr-rGO-ZnO and Ei-rGO-ZnO nanocomposites respectively. The enhanced photocatalytic activity of Ei-rGO-ZnO composites could be attributed to the strong interaction with the ZnO and the defect sites available in Ei-rGO. Graphical abstractGraphical abstract of the carried work.