Nanoparticle-decorated Graphene Oxide Research Articles

P‐Type Charge Transfer Doping of Graphene Oxide with (NiCo)1−yFeyOx for Air‐Stable, All‐Inorganic CsPbIBr2 Perovskite Solar Cells

AbstractThe precise regulation of interfacial charge distribution highly determines the power conversion efficiency of perovskite solar cells (PSCs). Herein, inorganic (NiCo)1−yFeyOx nanoparticle decorated graphene oxide (GO) is successfully demonstrated as a hole booster for all‐inorganic CsPbIBr2 PSC free of precious metal electrode. Arising from the spontaneous electron transfer induced p‐type doping of GO from edged oxygen‐containing functional groups to (NiCo)1−yFeyOx, the best all‐inorganic CsPbIBr2 PSC achieves an efficiency of 10.95 % under one standard sun owing to the eliminated paradox between charge extraction and charge localization in GO surface. Furthermore, the champion device exhibits an excellent long‐term stability at 10 % relative humidity without encapsulation over 70 days because of the suppressed ions migration.

Electrocatalytic performance of the cobalt oxide nanoparticles decorated graphene oxide over the detection of folic acid

Herein, we Design and synthesis of a composite material consisting of cobalt oxide anchored on graphene oxide (Co3O4@GO) as an electrode modifier, and their application to the detection of folic acid (FA) has been investigated. The integration of Co3O4 and GO is by hydrothermal assisted synthesis route. The morphology and crystalline structure of the Co3O4@GO has been well analyzed by XRD, XPS, FESEM, HR-TEM, and EDX analysis. The electrochemical test of the Co3O4@GO modified electrode shows an interesting electrochemical performance for the selective determination of FA with a broad concertation range of 0.1-4000 µM and a lower detection limit (LOD) of 0.024 µM. The enhancement in the catalytic activity of Co3O4@GO can be achieved by the synergistic effect of Co3O4and GO, high electron transportation, and unique spherical structure of Co3O4@GO. The newly developed Co3O4@GO sensor also displays excellent sensitivity of 47.23 µAµM−1 cm−2. Finally, this Co3O4@GO sensor is demonstrated for the detection of FA in the human urine sample with excellent recovery.

Synthesis, characterization, and antibacterial activity investigation of silver nanoparticle-decorated graphene oxide

Herein, silver/graphene oxide (Ag/GO) nanocomposite was fabricated by co-precipitation with green reducing agent and then was characterized with modern analytical techniques. The antibacterial activities were conducted via the effects of Ag/GO concentration, time, and pH. Results show that silver nanoparticles were uniformly distributed on the GO sheets nanosized of 17.65 ± 4.76 nm. The antibacterial performance was optimized at pH 5.6, eradicating P. aeruginosa in 180 min at 50 µg/mL Ag/GO concentration and S. aureus in 480 min at 300 µg/mL Ag/GO. This demonstrates the potential of Ag/GO as an antibacterial nanocomposite material.

Interfacial plasmonic effects of gold nanoparticle-decorated graphene oxides on the performance of perovskite photovoltaic devices

Incorporation of metal nanoparticles (NPs) that can trigger localized surface plasmon resonance (LSPR) is an effective method for improving the performance of photovoltaics. Herein, Au NP- decorated graphene oxides (AuNP@GO) are synthesized and incorporated into halide perovskite photovoltaics (HPPVs) to improve their efficiencies. The resulting HPPVs exhibit enhanced power conversion efficiencies (PCEs) under illumination at 1 sun and the device enhancement can be attributed to the LSPR effects of the AuNP@GO nanocomposites. More interestingly, from the external quantum efficiency (EQE) spectra, we find two spectral wavelength regimes where the EQE values are improved. Because the Au NPs are positioned at the interface between the buffer layer and the perovskite active layer, we attribute such unique “interfacial” plasmonic effects to the fact that the Au NPs are affected by the two dielectric environments surrounding them. Because solar radiation covers a broad wavelength range, the interfacial plasmonic effects should extend the spectral range of enhanced light absorption. Further, the potential of the AuNP@GO nanocomposites to enhance the performance of HPPVs under indoor lighting conditions is also evaluated.

Etched multicore fiber sensor using copper oxide and gold nanoparticles decorated graphene oxide structure for cancer cells detection

A compact, portable, label-free, and ultra-sensitive sensor is proposed to detect cancerous cells based on Multi-Core Fiber (MCF) comprising of seven cores arranged in a hexagonal shape spliced with Single-Mode Fiber (SMF). Here, cytosensing based on fiber optic Localized Surface Plasmon Resonance (LSPR) is used for the efficient detection of different types of cancer cells. The proposed sensor structure is etched in a controlled manner to increase the evanescent wave (EWs) and coupling of modes between the cores of MCF. The etched MCF based LSPR probe has high refractive index sensitivity (RIS). To further increase the sensitivity, the sensor structure is immobilized with different nanomaterials (NMs) such as optimized size of gold nanoparticles (AuNPs), graphene oxide (GO), and copper oxide nanoflowers (CuO-NFs). AuNPs increase the sensitivity using LSPR, whereas, GO and CuO-NFs helps to increase the biocompatibility of sensor. The developed probe is further coated with 2-deoxy-D-glucose (2-DG) over NMs that are specific for the detection of cancer cells. In this work, various cancerous cell lines i.e. HepG2, Hepa 1–6, MCF-7, A549, and normal cell lines i.e. NCF and LO2 are detected using the developed sensing probe. Various analysis of proposed sensor such as selectivity, reusability, anti-interference ability, and involvement of GLUT receptor in detection has also been performed. The proposed etched sensor is ultra-sensitive for detection of HepG2, Hepa1 6, A549, MCF-7, LO2, and NCF cell lines with a limit of detection (LoD) of 3, 2, 2, 2, 4, 10 cells/mL, respectively in the linear range of 1 × 102–1 × 106 cells/mL.

Silver nanoparticles decorated graphene oxide nanocomposite for bone regeneration applications

Different ultra-lightweight carbon nanostructures with superb mechanical properties have made them attractive materials for reinforcing nanocomposites. However, the preparation of an ideal bone reinforcement is still a challenging task. Therefore, in the present study, a simple wet chemistry method was employed to synthesize silver nanoparticles (AgNPs) decorated graphene oxide (GO) nanocomposite as potential reinforcement in orthopedic applications. A well-dispersed nearly oval-shaped AgNPs with the mean size of 9 ± 6 nm were homogeneously formed on the surface of GO due to its supporting role in preventing agglomeration of fine particles. The results of the antibacterial activities revealed that the anchor of AgNPs on the surface of GO improved its antibacterial properties, in which the composite structure exhibited higher antibacterial activity against Escherichia coli (E. coli) than Staphylococcus aureus (S. aureus) bacteria. The proposed protocol can keep steady the scattering of the AgNPs in nanocomposite and prolong the antibacterial activity of the system. Highlights AgNPs-GO nanocomposite was prepared via a facile wet chemistry approach. AgNPs (9 ± 6 nm) were homogeneously formed on GO. GO dictated the formation of nearly oval AgNPs in the system. The highest reactivity was found to be -0.315 eV.atom−1. Nanocomposite showed higher antibacterial activity versus E. coli than S. aureus bacteria.

Photocatalytic degradation of basic blue dye using zinc nanoparticles decorated graphene oxide nanosheet

AbstractReduced graphene oxide nanosheets were prepared by a modified hummer method and decorated with zinc nanoparticles to form nanocomposite (ZnO/RGO). The nanostructure surface materials of RGO with ZnO consist of different functional groups such as carboxyl, carbonyl, and hydroxyl groups, which facilitate the oxidation process of dye. Various techniques characterized the synthesized nanocomposites. Scanning electron microscopy (SEM) showed good surface morphology of ZnO/RGO, and X‐ray diffraction illustrated a high crystal structure of the surface. Fourier‐transform infrared spectroscopy (FTIR) shows the functional groups of nanocomposites ZnO/RGO. The Raman and X‐ray photoelectron spectroscopy (XPS) spectroscopies illustrate the surface and functional properties of ZnO/RGO catalyst. Moreover, the optical characterization achieved good value around 3.29 eV because of the decoration of ZnO on the surface of graphene oxide. Optimized conditions show up to 98% photocatalytic degradation of basic blue dye. Liquid chromatography–mass spectrometry was used for the analysis of degradation and intermediate identification. The proposed degradation mechanism of basic blue by the following steps, cleavage of C–C bonds in the benzene ring, and N‐N bond during the attack of OH• radicals, (iii) cleavage of aniline and C–C bonds of the benzene group.

Characterization and Preparation of Metallic Nanoparticles Decorated Graphene Oxide/ Carbon Nanotube on Polytetrafluoroethylene Membrane as an electrochemical Filter for Wastewater Treatment

Characterization and Preparation of Metallic Nanoparticles Decorated Graphene Oxide/ Carbon Nanotube on Polytetrafluoroethylene Membrane as an electrochemical Filter for Wastewater Treatment

Graphene Templated DNA Arrays and Biotin-Streptavidin Sensitive Bio-Transistors Patterned by Dynamic Self-Assembly of Polymeric Films Confined within a Roll-on-Plate Geometry.

Patterning of surfaces with a simple strategy provides insights into the functional interfaces by suitable modification of the surface by novel techniques. Especially, highly ordered structural topographies and chemical features from the wide range of interfaces have been considered as important characteristics to understand the complex relationship between the surface chemistries and biological systems. Here, we report a simple fabrication method to create patterned surfaces over large areas using evaporative self-assembly that is designed to produce a sacrificial template and lithographic etch masks of polymeric stripe patterns, ranging from micrometer to nanoscale. By facilitating a roll-on-plate geometry, the periodically patterned surface structures formed by repetitive slip-stick motions were thoroughly examined to be used for the deposition of the Au nanoparticles decorated graphene oxide (i.e., AuNPs, ~21 nm) and the formation of conductive graphene channels. The fluorescently labeled thiol-modified DNA was applied on the patterned arrays of graphene oxide (GO)/AuNPs, and biotin-streptavidin sensitive devices built with graphene-based transistors (GFETs, effective mobility of ~320 cm2 V−1 s−1) were demonstrated as examples of the platform for the next-generation biosensors with the high sensing response up to ~1 nM of target analyte (i.e., streptavidin). Our strategy suggests that the stripe patterned arrays of polymer films as sacrificial templates can be a simple route to creating highly sensitive biointerfaces and highlighting the development of new chemically patterned surfaces composed of graphene-based nanomaterials.

Optimization of the antibacterial activity of silver nanoparticles-decorated graphene oxide nanocomposites

In this study, silver/graphene oxide (Ag/GO) nanocomposites were synthesized using the in situ method. Glucose was selected as an eco-friendly reducing agent for the reduction of Ag+ into silver nanoparticles (AgNPs). The characterization of GO and Ag/GO with Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscopye, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Results showed that Ag/GO was successfully synthesized. Silver nanoparticles (AgNPs) with an average size of 17.68 ± 4.48 nm were uniformly distributed onto GO sheets. The antibacterial activity of GO, AgNPs, and Ag/GO were tested against Staphylococcus aureus ATCC 25,923 (S. aureus) and Salmonella enterica ATCC 35,664 (S. enterica) bacteria by optical density and plate colony–counting methods. Test results showed that Ag/GO had higher antibacterial activity than its precursors (bare AgNPs and GO) with a bactericidal rate of more than 99.90 %. Thus, Ag/GO was selected for further experimentation. Simultaneous effects of the interaction time, Ag/GO concentration, pH, annealing temperature, and S. aureus density on the antibacterial activity of Ag/GO were also investigated with full factorial experimental design according to Placket–Burman and Box–Behnken designs. After 10 min of interaction time at 37 °C, the optimal values of these factors were determined to be: Ag/GO concentration of 48 μg/mL, pH 5, and S. aureus density 5.3 × 106 CFU/mL, corresponding to an antibacterial capacity of 99.95 % towards S. aureus. The presented experiment confirmed Ag/GO to be able of eliminating about 99.99 % of S. aureus. All results of the present study affirmed the potential applications of Ag/GO as an antibacterial agent in the medical field.

Mesoporous Iron Oxide Nanoparticle-Decorated Graphene Oxide Catalysts for Fischer–Tropsch Synthesis

Hierarchically mesoporous iron oxide/graphene oxide (GO) composites have been synthesized by a facile, one-step hydrothermal method and utilized as Fischer–Tropsch synthesis (FTS) catalysts. The ca...

Enhanced electrocatalytic activity towards urea oxidation on Ni nanoparticle decorated graphene oxide nanocomposite

Hydrogen production from natural resourses and industrial waste water is of vital and duel importance to the energy and environmental issues. Urea oxidation based on cost effictive catalyst and which is substuation to the noble based electrolysers like Pt, Pd and Rh of great challange. Herein, we have fabricated effective decoration of Ni NPs on GO by chemical reduction approach and characterized by Furrier transfarm infra red (FTIR) spectroscopy, X-ray diffraction (XRD), transmissio electron microscopy (TEM), Raman spectroscopy, BET surface area measurements and X-ray photoelectron spectroscopy (XPS). In the morphological studies TEM confirms the Ni NPs (∼10 nm) on GO (∼20 nm thickness) and XRD confirms its FCC crystal structure. Further, Raman spectroscopic analysis showed the increment of ID/IG ratio more than double in GO compared to Ni@GO supports decoration of Ni NPs on GO. BET analysis also supports Ni@GO having higher surface area compared to Ni NPs and GO individuals, More significantly, binding energy of Ni is zero-valent confirmed from XPS of Ni@GO. Electrochemical activity of Ni@GO from cyclic voltammetry (CV) shows the ultrahigh current density is of 27 mA/cm2 at an ultralow onset potential of 0.30 V vs SCE having long term stability. Electrochemical impedance spectroscopy (EIS) shows the highly sensitive towards the urea oxidation reaction on Ni@GO nanocomposite. The electrocatalytic activity on Ni@GO is pH sensitive towards urea oxidation.

Silver and copper oxide nanoparticles-decorated graphene oxide via pulsed laser ablation technique: Preparation, characterization, and photoactivated antibacterial activity

Graphene oxide, silver and copper oxide nanoparticles display photoactivated antibacterial behavior owing to their ability to generate charge carriers via light exposure. In this work, silver nanoparticles (AgNPs) and copper oxide nanoparticles (CuONPs) were embedded through graphene oxide (GO) using laser ablation technique. The microstructural behavior of the synthesized compositions has been investigated via XRD and TEM. The optical properties were studied by (UV–Vis), while the antibacterial properties were investigated in addition to the cell viability towards normal cell line (HFB4) in vitro. The antibacterial activity of GO was enhanced significantly with addition nanoparticles; by meaning, the inhibition zone enlarged from 5.4 mm with pure GO to be around 11.2 mm against E. coli with contribution of CuONPs. This trend of enhancement suggests that GO could be a great platform for different kinds of photo-activated antibacterial to be recommended for versatile biomedical applications.

Hydrogen storage mechanism in transition metal decorated graphene oxide: The symbiotic effect of oxygen groups and high layer spacing

Transition metal nanoparticle decoration is widely used to enhance the hydrogen storage properties of carbon materials. However, little efforts have been devoted to unveil structural interaction between nanoparticles and substrate and understand the underlying kinetic mechanism for hydrogen sorption. In this work, a suite of TiO2 nanoparticles decorated graphene oxide (GO) composites is fabricated and characterized to determine the interactions between material structure and hydrogen storage kinetics. EELS and XPS results show that interactions between nanoparticles and GO cause changes of the chemical states of C–O, CO and C–OH groups; furthermore, reactions of C–OH, HO–CO and C–O–C groups with TiO2 nanoparticles create C–Ti and Ti–O–C bonding. Decoration of TiO2 nanoparticles improves the capacity of GO by 2.3×, and 80% of the adsorption is reversible. By means of semi-empirical kinetic analysis, it is determined that hydrogen adsorption is controlled by two-dimensional diffusion regardless of layer spacing; while desorption is controlled by multiple diffusion processes and is sensitive to layer spacing. Collectively, these new findings deepen the understanding of transition metal nanoparticles decorated GO materials in the aspects of nanoparticle incorporation and hydrogen storage kinetic mechanism. In particular, oxygen groups enhance nanoparticle decoration, while high layer spacing improves desorption kinetics and reversibility.

Mechanical and anticorrosive properties of epoxy containing modified graphene Oxide hybrids

The present study investigates the effect of filler loading onto the mechanical and anticorrosive properties of epoxy based polymer nanocomposites. Zinc Oxide nanoparticles decorated graphene oxide (GO-ZnO) hybrids were synthesized with the aid of silane coupling agents and was incorporated as fillers in epoxy. The epoxy nanocomposite were fabricated at different filler loading (0.001 wt%, 0.01 wt%, 0.1 wt% and 0.5 wt%). A remarkably low percolation threshold of 0.01 wt% is achieved in the GO-ZnO/Epoxy system having the highest tensile strength and Young’s Modulus (47 MPa and 30 MPa respectively), compared to bare epoxy that have the lowest tensile strength and Young’s Modulus of 24 MPa and 14 MPa respectively. Meanwhile, the protection efficiency of the nanocomposite is the highest at the filler loading percentage of 0.1 wt% with a value of 61% after exposed to 3.5 wt% NaCl for 14 days. Therefore, the trade-off relationship between the mechanical properties and corrosion protection are discussed.

Au/NiFe2O4 nanoparticle-decorated graphene oxide nanosheets for electrochemical immunosensing of amyloid beta peptide.

In the present work, an electrochemical immunosensor has been fabricated for the detection of amyloid beta peptide (βA1-–42) based on a gold nanoparticle/nickel ferrite decorated graphene oxide-chitosan nanocomposite (Au/NiFe2O4@GO-Ch) modified glassy carbon electrode (GCE) as an effective sensing platform. βA1–42 has been analyzed as a potential biomarker for its application in Alzheimer's disease monitoring. The combination of highly conducting Au and NiFe2O4 nanoparticles on two-dimensional GO nanosheets provides an excellent platform for sensitive and selective sensing applications. A miniaturized Au/NiFe2O4@GO-Ch/GCE immunosensor was prepared by immobilization of βA antibody onto Au//NiFe2O4@GO-Ch/GCE via carbodiimide coupling. Various characterization techniques were utilized in the study to estimate the morphological and electronic attributes of the components used to fabricate the immunosensor. Differential pulse voltammetry (DPV) was performed to study the amperometric response of the developed immunosensor as a function of βA1–42 concentration. The DPV results confirmed that the immunosensor detected βA1–42 selectively and demonstrated a wide linear range from 1 pg mL−1 to 1 ng mL−1 and a detection limit of 3.0 pg mL−1. Furthermore, the immunosensor also indicated its clinical viability by detecting βA1–42 in cerebrospinal fluid.

Au–Graphene Oxide–Anodic Aluminum Oxide Nanostructured Substrates for Surface-Enhanced Raman Spectroscopy Based Molecular Sensing

We present surface-enhanced Raman scattering (SERS) enhancement studies in a biocompatible and chemically stable plasmonic composite based on gold nanoparticle decorated graphene oxides deposited o...

Facile sonochemical synthesis of rutile-type titanium dioxide microspheres decorated graphene oxide composite for efficient electrochemical sensor.

In this reports the facile and green synthesis of rutile-type titanium dioxide nanoparticles decorated graphene oxide nanocomposite via the ultrasonication process (frequency: 50kHz, Power: 100W/cm2 and Ultrasonic type: Ti-horn). Because, the sonochemical synthesis method is simple, non-explosive and harmless method than other conventional technique. Furthermore, the synthesized material was characterized by various analytical techniques including FESEM, EDX, XRD, EIS and electrochemical methods. Then, the synthesized TiO2 MPs@GOS composite was applied for the electrocatalytic detection of theophylline (TPL) using CV and amperometric (current-time) techniques. Captivatingly, the modified sensor has excellent electrocatalytic performance with the wider linear range from 0.02 to 209.6µM towards the determination of theophylline and the LOD and sensitivity of the modified sensor was calculated as 13.26nM and 1.183μA·µM-1·cm-2, respectively. In addition, a selectivity, reproducibility and stability of the TiO2 MPs@GOS modified GCE were analyzed towards the determination of theophylline molecule. Finally, the real time application of TiO2 MPs@GOS modified theophylline sensor was established in serum and drug samples.

Removal of phosphate and nitrate ions aqueous using strontium magnetic graphene oxide nanocomposite: Isotherms, kinetics, and thermodynamics studies

AbstractMagnetic Fe3O4 nanoparticle decorated graphene oxide (GO) was modified with strontium nanoparticles (MGO‐Sr) and applied for enhanced removal of phosphate and nitrate ions from river and sewage water samples. The nanocomposite's features were investigated using Fourier transform‐infrared spectrometry, field emission‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray diffraction. The effective parameters, adsorption efficiency, regeneration, and field application of MGO‐Sr were also studied. Adsorption isotherm and kinetic models were applied for evaluation of experimental adsorption process. The data was in well comply with Langmuir isotherm and pseudo‐second‐order comparing with other models. Langmuir maximum adsorption capacity was obtained equal to 238.09 mg/g for phosphate and 357.14 mg/g for nitrate. Van't Hoff thermodynamic predicted an exothermic nature for adsorption process followed by a physisorption mechanism. The prepared nanocomposite provided a high‐removal efficiency toward phosphate and nitrate ions in river and sewage water. Hence, it is applicable in water remediation process.

Electrochemical detection of chloramphenicol using palladium nanoparticles decorated reduced graphene oxide

In this work, we developed a highly selective detection of chloramphenicol (CAP) using palladium nanoparticles decorated graphene oxide (rGO/PdNPs) nanocomposite. Moreover, the successful formation of rGO/PdNPs nanocomposite was verified by TEM, UV–Vis, FT-IR spectra, X-ray photoelectron spectroscopy (XPS). The electrochemical characteristics of the electrochemical sensor were evaluated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Furthermore, the rGO/PdNPs modified GCE displayed an excellent electroactivity in the presence of chloramphenicol as compared to that of modified and unmodified glassy carbon electrode (GCE). It showed an excellent performance with a linear response range of 50–1000 nM and the low detection limit of 50 nM (S/N = 3). In addition, the present promising sensor exhibited high sensitivity, good stability as well as remarkable reproducibility, and satisfactory recovery rate for CAP electrochemical detection in real samples.