Preparation of Silver Decorated Reduced Graphene Oxide Nanohybrid for Effective Photocatalytic Degradation of Indigo Carmine Dye

Background: Even though silver decorated reduced graphene oxide (Ag-rGO) shows max- imum absorptivity in the UV region, most of the research on the degradation of dyes using Ag-rGO is in the visible region. Therefore the present work focused on the photocatalytic degradation of indigo carmine (IC) dye in the presence of Ag-rGO as a catalyst by UV light irradiation. Methods: In this context, silver-decorated reduced graphene oxide hybrid material was fabricated and explored its potential for the photocatalytic degradation of aqueous IC solution in the UV region. The decoration of Ag nanoparticles on the surface of the rGO nanosheets is evidenced by TEM analysis. The extent of mineralization of the dye was measured by estimating chemical oxygen demand (COD) values before and after irradiation. Results: The synthesized Ag-rGO binary composites displayed excellent photocatalytic activity in 2 Χ 10-5 M IC concentration and 5mg catalyst loading. The optical absorption spectrum of Ag-rGO showed that the energy band-gap was found to be 2.27 eV, which is significantly smaller compared to the band-gap of GO. 5 mg of Ag-rGO was found to be an optimum quantity for the effective degrada- tion of IC dye. The degradation rate increases with the decrease in the concentration of the dye at al- kaline pH conditions. The photocatalytic efficiency was 92% for the second time. Conclusion: The impact of the enhanced reactive species generation was consistent with higher pho- tocatalytic dye degradation. The photocatalytic mechanism has been proposed and the hydroxyl radi- cal was found to be the reactive species responsible for the degradation of dye. The feasibility of reus- ing the photocatalyst showed that the photocatalytic efficiency was very effective for the second tim

Fabrication of 1D graphene nanoribbon and malenized linseed oil-based nanocomposite: a highly impervious bio-based anti-corrosion coating material for mild steel

Graphene nanoribbon (GNR) is a flat ribbon-like 1D nanomaterial of graphene family rarely explored in the development of anti-corrosion coatings. In the present work, a bio-based anti-corrosion coating was fabricated using GNR as nanofiller in malenized linseed oil (MLO) polymer network. MLO polymer network was first prepared from commercially available linseed oil by malenization reaction at 80 degrees C using maleic anhydride. Later, GNR was synthesized from multiwalled carbon nanotube by oxidative unzipping method and incorporated into MLO polymer network to obtain the bio-based MLO-GNR nanocomposite. The as-prepared MLO and MLO-GNR coating materials were spin coated onto bare mild steel samples and cured at 80 degrees C for 24 h. The morphology and surface characteristics of coatings were studied by spectroscopic and microscopic techniques. Further, the anti-corrosion behaviour of bare and coated MS samples was investigated by potentiodynamic polarization and electrochemical impedance methods in a 3.5% NaCl medium. Among the samples, MLO-GNRcoated samples exhibited a high level of corrosion inhibition in the saline medium compared to uncoated MS sample as the damages and destruction activity were more on its surface than their counterparts. MLO-GNR nanocomposite coating exhibited robust corrosion resistance activity and showed 99.9% protection efficiency. Further, the MLO-GNR coating displayed higher stability in the saline medium as well as open-air environment establishing that the flat GNR molecule acts as excellent nanofiller in MLO polymer network to produce robust anti-corrosion activity leading to protection of mild steel. GRAPHICS]

An efficient and eco-friendly anti-corrosive system based on Beeswax-Graphene oxide nanocomposites on mild steel in saline medium

The primary objective of the present work is to develop an eco-friendly effective corrosion-resistant coating on mild steel using beeswax (BW). The effect of graphene oxide (GO) nanofillers on the corrosion protection performance of BW on mild steel was studied. Nanocomposite coatings were prepared by incorporating different wt. % GO (0.05, 0.1, 0.3, and 0.5), into the BW matrix. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FT-IR) and Raman Spectroscopy. All coatings were done using the dip-coating method and the surface properties of the coated samples were analyzed using Contact angle, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Barrier and corrosion protection performance of the coated samples were monitored using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods in 3.5% NaCl medium. The results of the study brought out that the addition of GO into the BW matrix enhances the coating barrier performance and makes the electrolyte penetration pathway longer and more circuitous due to its high surface area. The amount of GO in the coating matrix also has a greater influence in improving the corrosion resistance of BW coatings. Among nanocomposites with different GO wt.%, coatings prepared via the addition of 0.1 wt.% GO to BW matrix show outstanding barrier properties and superior corrosion protection under NaCl electrolyte. The corrosion rate of Pure BW coating was reduced to 470 fold after the introduction of 0.1 wt.% of GO

Fabrication of ZnO/rGO and ZnO/MWCNT nanohybrids to reinforce the anticorrosion performance of polyurethane coating

Polyurethane (PU) has been widely utilized in different applications due to its unique properties. Substantial attempts have been made to enhance the corrosion resistance and mechanical properties of PU coating through the addition of nanomaterials. In this study, zinc oxide/reduced graphene oxide (ZnO/rGO) and zinc oxide/multiwalled carbon nanotube (ZnO/MWCNT) nanohybrids were synthesized and incorporated into the PU matrix to enhance the anti-corrosion property of the PU coating. The synthesized nanofillers were thoroughly characterized through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray spectroscopy (EDX). The rGO/ZnO-PU and MWCNT/ZnO-PU nanocomposites, and also neat PU were coated on the mild steel (MS) substrate, and the surfaces of the coated samples were probed by Contact angle technique, Atomic Force Microscopy (AFM), and SEM analysis. Electrochemical impedance spectroscopy and potentiodynamic polarization tests were carried out to examine the effects of rGO/ZnO and CNT/ZnO nanofillers in improving the protection and barrier properties of pure PU coating. Electrochemical corrosion data revealed the superior anticorrosion efficiency for rGO/ZnO decorated PU coating (99.09%) compared to that of MWCNT/ZnO dispersed PU coating (95.24%). The high surface area and aspect ratio of rGO make it an effective nanofiller in reinforcing the PU matrix for anticorrosion application

Development of Al2O3.ZnO/GO-phenolic formaldehyde amine derivative nanocomposite: A new hybrid anticorrosion coating material for mild steel

The hybrid nanocomposites are least explored materials in anti-corrosion application. In this context, Al2O3 center dot ZnO and Al2O3 center dot ZnO/GO nanocomposites were prepared and dispersed in the synthesized phenolic formaldehyde amine derivative (PFAd) polymer. The structural and the elemental composition of the nanocomposites and PFAd were ascertained through Fourier transfer infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Energy dispersive X-ray spectroscopy (EDX) and Transition electron microscopy (TEM). The 0.2 wt.% of nanofiller was chosen as an optimum composition to obtain uniform dispersion in PFAd matrix. The surface morphology, texture and chemical composition of the coatings on mild steel (MS) surface have been studied by XRD and Scanning electron microscopy (SEM). The anti-corrosion performance of the coatings on MS in 3.5 wt.% NaCl solution was evaluated by electrochemical techniques. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) data revealed that, Al2O3 center dot ZnO/GO dispersed PFAd shows very good R-coat (3.81 x 10(2) ohm cm(2)) and R-ct (1.84 x 10(3) ohm cm(2)) with reasonably lower i(corr) (1.233 x 10(-3 )A/cm(2)) values even after 68 days of immersion. Further, it was found that, the barrier property of the coating depends on the composition and dispersibility of the fillers in the polymer matrix

Functionalized graphene oxide dispersed polyvinyl alcohol-epoxidized linseed oil composite: An eco-friendly and promising anticorrosion coating material

Polyvinyl alcohol (PVA) is an extensively used biodegradable polymer including corrosion inhibition, but it fails to withstand long time protection due to water solubility. The present work emphasized an efficient way to transform PVA to hydrophobic nature and further modification for corrosion protection of mild steel (MS). In this backdrop, PVA was blended with varying amounts of the synthesized amine-functionalized graphene oxide (AGO) and then assimilated with the epoxidized linseed oil (ELO). The fabricated composite material was coated on MS surface by the doctor's blade technique, and their adhesion character, roughness, wettability, and sus-tainability in saline media were confirmed by atomic force microscopy (AFM), contact angle, and electro-chemical techniques. The chemical bonding as well as structural interactions of the prepared AGO were ascertained by Fourier-transform infrared (FT-IR), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) methods. Electrochemical impedance spectroscopy (EIS) measurements of the PVA coatings showed improved Nyquist semicircle diameter by increasing the AGO content, and the potentiometric polari-zation (PP) data supports the EIS results. The different weight percentages of AGO dispersed PVA/ELO composite coatings revealed enormous changes in their Nyquist, Bode, and phase angle plots. The highest impedance and charge transfer resistance of PVA/ELO-AGO (0.25 wt%) coating are found to be 10(8.6) omega cm(2) and 4.541 x 10(8) omega cm(2), respectively. Further, the composite coating was sustained for 20 days in 3.5 wt% NaCl solution showing its enhanced barrier property. This can be ascribed due to the strong cross-linkages in PVA/ELO-AGO that makes it a durable and promising anti-corrosion coating material

Functionalized graphene oxide-epoxy phenolic novolac nanocomposite: an efficient anticorrosion coating on mild steel in saline medium

The present paper reports the fabrication of efficient anticorrosion coating material on mild steel using epoxy phenolic novolac (EPN) polymer. The EPN was prepared by refluxing the mixture of phenol formaldehyde amine and epoxy in a 1:1 weight ratio and characterized by H-1 NMR and FT-IR spectral studies. The graphene oxide (GO) was functionalized using 2-{4-2-hydroxy-3-(propan-2-ylamino) propoxy] phenyl} acetamide and thoroughly characterized by FT-IR, Raman, and energy dispersive X-ray spectroscopies and TEM techniques. The anticorrosion performance of the coated mild steel (MS) samples was studied by electrochemical impedance spectroscopy and potentiodynamic polarization techniques in 3.5 wt% NaCl medium. The results revealed that the anticorrosion ability of EPN coating was significantly enhanced by the incorporation of functionalized graphene oxide (FGO). The corrosion inhibition efficiency of 99.99% is achieved with 0.2 wt% FGO-grafted EPN matrix. Graphical abstrac