Functionalized Graphene Nanocomposite Research Articles

Design and Fabrication of Silver Nanoparticles Doped β-cyclodextrin-chitosan Functionalized Graphene Nanocomposite Modified Electrode for Determination of Cu(II)

Introduction: In this study, a nanocomposite film was prepared by doping silver nanoparticles onto β-cyclodextrin-chitosan functionalized Reduced Graphene Oxide (RGO), denoted as Ag/ β-CD/CS/G nanocomposite. The average diameter of the Ag NPs was found to be 62±17 nm. Methods: The fabricated composite was applied to monitor trace levels of copper ions in different industrial and environmental water samples. The morphology and microstructure of the fabricated sensor were extensively investigated using different techniques, including XRD, TGA, HR-TEM, FTIR, SEM, XPS, and EDX physicochemical techniques. For the electrochemical monitoring of Cu(II), the Ag/β-CD/CS/G nanocomposite electrode showed remarkable performance in terms of high sensitivity and a low limit of detection that was found to be 0.24 nmol L-1. Results: The developed sensors showed a linear dynamic range from 10-3 to 10-8 mol L-1 with an R2 of 0.99. The impacts of different electrochemical parameters, including medium pH, scanning rate, and interfering ions, were investigated. Conclusion: Furthermore, the fabricated modified electrode showed high efficiency for Cu(II) detection in groundwater samples.

Photodynamic impact of curcumin enhanced silver functionalized graphene nanocomposites on Candida virulence

Candida species are escalating resistance to conventional antifungal treatments, intensifying their virulence, and obstructing the effectiveness of antifungal medications. Addressing this challenge is essential for effectively managing Candida infections. The overarching objective is to advance the development of more efficient and precise therapies tailored to counter Candida infections. This study focuses on developing antifungal combined drugs using curcumin-enhanced silver-functionalized graphene nanocomposites (Cur-AgrGO) to effectively target key virulence factors of C. albicans, C. tropicalis, and C. glabrata (Candida spp.). The green reduction of graphene oxide (GO) using bioentities and active molecules makes this approach cost-effective and environmentally friendly. The nanocomposites were characterized using various techniques. Combining Cur-AgrGO with photodynamic therapy (PDT) demonstrated effective antifungal and antibiofilm activity with delayed growth and metabolism. The nanocomposites effectively suppressed hyphal transition and reduced key virulence factors, including proteinases, phospholipases, ergosterol levels, and cell membrane integrity. The findings suggest that Cur-AgrGO + PDT has potential as a treatment option for Candida infections. This innovative approach holds promise for treating Candida infections.Graphical abstract

A single functionalized graphene nanocomposite in cross flow module for removal of multiple toxic anionic contaminants from drinking water.

Polyether sulfone (PES)-based thin-film nanofiltration (TFN) membranes embedded with ferric hydroxide (FeIII(OH)x) functionalized graphene oxide (GO) nanoparticles were fabricated through interfacial polymerization for a generalized application in removal of a plethora of anionic and toxic water contaminants. Following the most relevant characterization, the newly synthesized membranes were fitted in a novel flat sheet cross-flow module, for experimental investigation on purification of live contaminated groundwater collected from different affected areas. The separation performances of the membranes in the flat sheet cross-flow module demonstrated that GOF membranes had higher selectivity for monovalent and divalent salt rejections than pristine GO membranes. Furthermore, both membranes were tested for simultaneously removing widely occurring hazardous ions of heavy metals and metalloids in groundwater, such as arsenic, selenium, chromium, and fluoride. Compared to the pristine GO and the reported membranes in the literature, the GOF membrane exhibited remarkable performance in terms of rejection efficiency (Cr (VI): 97.2%, Se (IV): 96.6%, As(V): 96.3%, F- 88.4%) and sustained flux of 184 LMH (Lm-2h-1) at an optimum transmembrane pressure of 16bar. The investigated membrane module equipped with the GOF membrane proved to be a low-cost system with higher anionic rejection and sustained high flux at a comprehensive pH range, as evident over long hours of study vis-à-vis reported systems.

A new antioxidant made from a pterostilbene functionalized graphene nanocomposite as an efficient treatment for dry eye disease.

Dry eye disease is a common condition that affects the eyes. It is caused by problems with the tear film and the tear dynamics. Dry eye can be caused by an increase in the amount of reactive oxygen species (ROS) in the corneal epithelium. The treatment for dry eye typically focuses on relieving the uncomfortable symptoms by using eye drops such as artificial tears, antibiotics, and by using anti-inflammatory/immunosuppressive agents such as cyclosporine, and lifitegrast. However, the recovery of patients with dry eye can take several years particularly if the symptoms are severe. This is because the present treatment approaches for dry eye are not based on its cause, e.g., the oxidative stress arising from the rapid increase in ROS. This work describes a new type of antioxidant made from pterostilbene (PS) and carboxyl-chitosan modified graphene (CG). The use of a hydrophilic two-dimensional CG nanosheet to improve the properties of PS is reported. Superior enhanced properties including better cellular permeability, long sustained release period (over 30 h), and antioxidant properties, were realized by using PS-CG. A hyperosmotic (HS) damaged human corneal epithelial cell (HCEC) model was used for antioxidant tests. This model has an intracellular ROS level 4 times more than that of a control group. The ROS content was declined efficiently to the same amount as normal cells in the PS-CG treated HS group. There was a significant decline in the content of lactate dehydrogenase (LDH) and the apoptosis rate of HCEC in the PS-CG treated HS group when compared to that seen in the HS model. Real-time polymerase chain reaction (PCR) and western blots (WB) were used to understand the antioxidant mechanism of PS-CG. The results showed that the antioxidant was working by activating the Keap1-Nrf2-ARE signalling pathway. In vivo testing testing using a dry eye mouse model suggested that the PS-CG acted as an efficient antioxidant. More tear production and healthier corneal and conjunctival epithelial cells were achieved when PC-CG was applied to this model. The use of PS-CG could be a new strategy for treating dry eye and other ocular diseases caused by ROS.

One-Step Chemiluminescent Determination of Glucose by a Functionalized Graphene Nanocomposite

A chemiluminescence (CL) nanosensing platform was constructed by using reduced graphene oxide (rGO) as the carrier, which was loaded with N-(aminobutyl)-N-(ethylisoluminol) (ABEI) as the signaling molecule, hemin as the catalyst, and glucose oxidase (GOx) as the enzyme. The loading efficiency of GOx was determined to be 0.64 mg GOx/mg rGO. The nanosensing platform achieved one-step determination of glucose without pre-incubation steps. When glucose is added to the CL nanosensing platform, the GOx on the nanocomposite catalyzes the reaction between glucose and O2 to produce H2O2 which oxidizes ABEI to emit light with the catalysis of hemin. When glucose was mixed with the nanocomposite, a growth-type CL profile was observed and the maximum signal was obtained approximately 6 min after the addition of glucose to the nanocomposite. The CL nanosensing platform exhibited a linear enhanced response for glucose from 10 μM to 1 mM. The detection limit for glucose was 2.6 μM. The proposed glucose CL sensing platform also exhibited good selectivity and specificity. Furthermore, it was successfully applied in the determination of glucose in serum, and satisfactory recoveries were obtained, signifying its potential in clinical diagnosis.

Cerium functionalized graphene nano-structures and their applications; A review

Graphene-based nanomaterials with remarkable properties, such as good biocompatibility, strong mechanical strength, and outstanding electrical conductivity, have dramatically shown excellent potential in various applications. Increasing surface area and porosity percentage, improvement of adsorption capacities, reduction of adsorption energy barrier, and also prevention of agglomeration of graphene layers are the main advantages of functionalized graphene nanocomposites. On the other hand, Cerium nanostructures with remarkable properties have received a great deal of attention in a wide range of fields; however, in some cases low conductivity limits their application in different applications. Therefore, the combination of cerium structures and graphene networks has been widely invesitaged to improve properties of the composite. In order to have a comprehensive information of these nanonetworks, this research reviews the recent developments in cerium functionalized graphene derivatives (graphene oxide (GO), reduced graphene oxide (RGO), and graphene quantum dot (GQD) and their industrial applications. The applications of functionalized graphene derivatives have also been successfully summarized. This systematic review study of graphene networks decorated with different structure of Cerium have potential to pave the way for scientific research not only in field of material science but also in fluorescent sensing, electrochemical sensing, supercapacitors, and catalyst as a new candidate.

Potent antibacterial activity of MXene-functionalized graphene nanocomposites.

Two dimensional (2D) nanomaterials display properties with significant biological utility (e.g., antimicrobial activity). In this study, MXene-functionalized graphene (FG) nanocomposites with Ti3C2T x in varying ratios (FG : Ti3C2T x , 25 : 75%, 50 : 50%, and 75 : 25%) were prepared and characterized via scanning electron microscopy, scanning electron microscopy-energy dispersive X-ray (SEM-EDX), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Their cytotoxicity was assessed using immortalized human keratinocytes (HaCaT) cells at three different timepoints, and antibacterial activity was assessed using Gram-positive Methicillin resistant Staphylococcus aureus, MRSA, and Gram-negative neuro-pathogenic Escherichia coli K1 (E. coli K1) in vitro. The nanomaterials and composites displayed potent antibacterial effects against both types of bacteria and low cytotoxicity against HaCaT cells at 200 μg mL-1, which is promising for their utilization for biomedical applications.

Mechanical behavior of carboxylic functionalized graphene reinforced polyurethane nanocomposites under static and dynamic loading

AbstractThe present work reports formation of polyurethane (PUR) and carboxylic functionalized graphene (COOH‐fG) nanocomposites via solution mixing method and static and dynamic mechanical characterization with dynamic mechanical analysis (DMA), nano indentation, and tensile and compressive testing. Magnetic stirring of the solutions of PUR in N,N dimethylformamide (DMF) and COOH‐fG in DMF was performed for different compositions of filler, 1%, 3%, 5%, 7%, and 10%, which were heated to obtain nanocomposite films followed by injection molding to cast into samples. Uniform dispersion and good intercalation were observed upon characterization by field emission scanning electron microscopy and X‐ray diffraction techniques. DMA showed that the storage modulus improved with increasing frequency of loading, and a linear decrement in the damping factor with an increase in the concentration of filler was observed. The maximum depth of indent in nano‐indentation test showed a decreasing trend, indicating improvement in nanohardness and elastic modulus with an optimum obtained at 5 wt% composition. An improvement in tensile modulus, tensile strength, and toughness, which were more substantial at lower compositions of filler, was observed. An optimum compressive modulus was obtained for 10 wt% of filler due to more resistance provided by graphene plates to compression as compared to PUR.

A Novel Phosphorus/Silicon-Containing Flame Retardant—Functionalized Graphene Nanocomposite: Preparation, Characterization and Flame Retardancy

A novel compound (DOPO-V-PA) containing phosphorus and silicon elements was grafted onto the surface of graphene oxide (GO) to obtain a graphene-based flame retardant (GO–DOPO-V-PA). The structure of GO-DOPO-V-PA was characterized and confirmed by FTIR and XPS spectra. AFM measurements showed that the average height of GO-DOPO-V-PA was thicker than that of GO and that the surface of GO-DOPO-V-PA was not uniform, contrary to the surface of the initiator GO before modification. The thermal stability of GO-DOPO-V-PA was greatly improved by the functionalization of GO with DOPO-V-PA, and the residual char of GO-DOPO-V-PA at 600°C increased from 16.45 (GO) to 61.44 wt %. After GO-DOPO-V-PA was incorporated into epoxy resin (EP), the residual char of EP/GO-DOPO-V-PA was almost 3 wt % higher than that of pure EP and EP/GO. Furthermore, EP/GO-DOPO-V-PA exhibited excellent flame retardancy. Compared to the pure EP and EP/GO, the peak heat release rate (pHRR) and total heat release (THR) of EP/GO-DOPO-V-PA both decreased, which was probably caused by the higher residual char of EP/GO-DOPO-V-PA during combustion. Thus, the flame retardancy of the graphene-based composites was improved with the addition of 2 wt % GO-DOPO-V-PA, which was much less than the previously known flame retardant systems, and the graphene has been demonstrated its excellent performance in the fire safety of the polymer materials.

Uptake of azaarenic 2-Methylpyridine by pre-cooled carboxyl functionalized graphene nanocomposite: Detection, sorption and optimization

Sizable concentration (2.5–20 mg L−1) of refractory solvent 2-methylpyridine (2Mp) was detected in textile industry effluent that had been subjected to conventional biological treatment prior to discharge. A ratio of 55:45 (acetonitrile to water) was determined for HPLC detection of 2Mp. A novel adsorbent, exfoliated, carboxylic graphene oxide nanocomposite (GON) was synthesized with emphasis on pre-cooling to throttle synthesis exothermicity. Removal characteristics of GON were compared to commercially sold activated carbon (SAC). Similar BOD/COD ratio of the effluent (0.24) and synthetic 2Mp samples (0.22) were observed. SEM, FTIR, EDS, XRD and stability studies were carried out for GON pre-sorption and post-sorption of 2Mp leading to an understanding of interaction mechanism. Batch studies showed GON exhibiting ten times the adsorption capacity (1.5 g L−1), neutral operation pH (7), lower contact time (90 min), better thermodynamic stability and structural disintegration resistance than SAC. Kinetics (pseudo-second kinetics, distinct intraparticle diffusion phases) and equilibrium studies with χ2 error minimization (best fit isotherm - Redlich-Peterson) were conducted. Removal data was optimized by 4-Factor Doehlert design (DD) involving temperature, GON dosage, pH and initial 2Mp concentration. The model suggested a strong relation between neutral pH of solution and 2Mp removal efficiency. DD predicted pH = 7.04, GON dosage = 1.80 g L−1, initial 2Mp loading = 16.89 mg L−1 and temperature = 293.82 K as optimal conditions with a removal of 72.10 %. A high R2 = 0.992 and error < 2% suggests that the developed model was in coherence with experimental 2Mp-GON sorption results and successful in its prediction.

Graphene-based intumescent flame retardant on cotton fabric

We have developed functionalized graphene oxide (FGO) nanocomposites-based intumescent flame-retardant coating. The graphene surface was functionalized by potassium carbonate by reacting graphene oxide (GO) and potassium carbonate (K2CO3). The resultant coating improved the flame retardancy of the cotton fabric. The FGO nanocomposite-coated fabric was to prove the flame retardancy properties of the FGO nanocomposite, by detail flame tests such as limiting oxygen index, vertical flammability test and exposure to the Bunsen burner flame (~ 1500 °C) test. FGO-coated material, when exposed to fire, was observed to maintain its original shape with the release of little smoke initially and later developed char-like material. Prepared materials were characterized by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. The cotton fabric alone burnt in 5 s, but when coated with the FGO, it was able to withstand the fire for more than 325 s (5.25 min), whereas the only GO- and K2CO3-coated fabrics were completely burned out within 10 s and 20 s, respectively. This obtained FGO nanocomposite coating is proved to be an efficient flame retardant with an easy, simple one-pot and inexpensive technique in comparison with the reported works. In this work, we have synthesized functionalized graphene nanocomposites, which act as an efficient flame retardant. The recent process established that this is a simple and eco-friendly method for efficient graphene-functionalized IFR.

Ameliorating the activity and stability of β galactosidase by tailoring potential nanobiocatalyst on functionalized nanographene: Headway to lactose hydrolysis

The ever-growing occurrence of intolerance to dairy products has led to an enormous requirement for immobilization of β galactosidase. In this report, we have shown the immobilization of β galactosidase onto polyaniline doped magnetic graphene (Fe3O4@PANI-GO) nanocomposite. A comparative analysis has been carried out for the integration via physical adsorption and covalent binding methods onto functionalized graphene nanocomposite for analytical application based on lactose reduction. The higher immobilization yield was exhibited in the case of the covalently bound enzyme with ƞ (effectiveness factor) value of 1.49. Characterization of functionalized graphene was studied by scanning and transmission electron microscope, and Fourier-transform infrared spectroscopy studies. Shift of pH optima was observed for covalently bound enzyme from pH 4.5 to 5. The immobilized β galactosidase displayed temperature optima similar to the soluble enzyme at 50 °C. Covalently bound enzyme retained 80% activity even after its 10th successive reuse. The immobilized enzyme displayed higher lactose reduction from milk than the free enzyme. Our conclusions have framed the way for the establishment of graphene-based nanobiosensor to upgrade the quality of milk and its products for easy assimilation by the lactose intolerant patients.

Doxorubicin Loaded Green Synthesized Nanoceria Decorated Functionalized Graphene Nanocomposite for Cancer-Specific Drug Release

In the present study design, the PEGylated nanoceria decorated reduced graphene nanocomposite (RGO-CeNPs-PEG) was successfully prepared by eco-friendly non-toxic green synthesis following syn-graphenization method, and evaluated as an efficient and reliable pH-sensitive nano-carrier. During green synthesis, aqueous leaf extract of Azadirachta indica (neem) was used as a reducing agent and the graphene oxide (GO) was activated by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide for covalent functionalization by methoxy amino polyethylene glycol. The prepared Smart pH stimuli responded nanoplatform was thoroughly characterized by various analytical techniques. The values of average particle size and hydrodynamic diameter of naturally prepared nanoceria may be suitable for biomedical application. Considering drug loading and release studies, it may be concluded that the higher drug loading and more pH-responsive release of DOX from RGO-CeNPs-PEG lead to a promising nanocarrier for the anticancer drug. Furthermore, DOX-loaded RGO-CeNPs-PEG had lesser harmful effect on normal cells than cancer cells as compared with free DOX, while increased cytotoxicity was evidenced on the cancer cell line against the former sample than the covalently conjugated RGO-PEG-DOX. So, the successful distribution and release of the anticancer drug into acidic microenvironment of the cancerous cells would bring about excellent therapeutic efficacy with reduced side effects than pure GO.

Solution Casting of Polyvinyl Alcohol–Functionalized Graphene Nanocomposites

Abstract Graphene materials have attracted enormous academics and industries in different fields, ranging from nanocomposites to medical applications, to explore due to its outstanding thermal, barrier and mechanical properties. In this work, the solution-casted polyvinyl alcohol (PVA) film reinforced with functionalized sonication exfoliated graphene and its properties such as sub surface mechanical behavior i.e hardness and modulus were studied. The compatibility between graphene and PVA was enhanced by the functionalization of graphene with a gum arabic. The decoration of the graphene surface allowed better interfacial interactions with PVA. As been observed during morphological study by scanning electron microscopy (SEM) and x-ray diffraction (XRD), agglomeration of graphene sheets was detected at highest graphene loading (0.10 wt.%). Improvement of mechanical properties was observed by nanoindentation for sample with lowest graphene contents (0.05 wt%). The enhancement of modulus up to 130% was contributed by homogeneously distributed graphene in the matrix of PVA. However, the present of higher graphene content seem to reduce of the hardness properties of PVA/graphene nanocomposites.

Solvent-free production of nano-FeS anchored graphene from Ulva fasciata: A scalable synthesis of super-adsorbent for lead, chromium and dyes

Here we demonstrate, a simple and solvent-free synthetic route for the production of FeS/Fe(0) functionalized graphene nanocomposite (G-Fe) via a one-step pyrolysis of seaweed biomass (Ulva fasciata). It is proposed that the natural abundance of both inorganic and organic sulfur in the seaweed induces the reduction of exfoliated graphitic sheets at elevated temperatures. FeCl3 was employed both as the iron precursor as well as the templating agent. Iron doping played a dual-faceted role of exfoliating as well as activating agent, producing composite with high adsorption capacity for Pb2+ (645 ± 10 mg/g), CR (970 mg/g), CV(909 mg/g), MO (664 mg/g), MB (402 mg/g) dyes and good recyclability (8 cycles). Pb2+ adsorption was irreversible even at low pH values and the spent composite (G-Fe-Pb) was utilized for efficient Cr(IV) removal (̴100 mg/g). The adsorption data followed the pseudo second order kinetics while the equilibrium data fitted perfectly into the Langmuir adsorption equation. Further, a thin layer of composite was deposited on a filter paper by vacuum filtration which was tested under continuous filtration mode for RB5 dye removal. Preliminary results highlight the potential of this composite to be used in pretreatment steps in hybrid membrane processes for filtration of complex wastewater feeds.

Room temperature Zinc-metallation of cationic porphyrin at graphene surface and enhanced photoelectrocatalytic activity

A stable zincporphyrin functionalized graphene nanocomposite was prepared by using positively charged cationic porphyrin (5,10,15,20-tetra(4-propyl pyridinio) porphyrin, TPPyP) and successive reduced graphene oxide (rGO) with tuned negative charge. The nanocomposite preparation was accompanied first by distinct electrostatic interactions and π-π stacking between TPPyP and rGO, and followed by fast Zinc-metallation at room temperature. In contrast to free TPPyP with Zn2+, the incorporation reaction is very slow at room temperature and heating or reflux conditions are required to increase the metallation rate. While at the surface of rGO nanosheet, the Zinc-metallation of TPPyP was greatly accelerated to 30min at 25°C in aqueous solution. The interaction process and composites formation were fully revealed by significant variations in UV–vis absorption spectra, X-ray photoelectron spectra (XPS) measurements, atomic force microscope (AFM) images, and fluorescence spectra. Furthermore, photoelectrochemical activity of resultant rGO/TPPyP-Zn nanocomposites was evaluated under visible-light irradiation, and enhancement of the photoelectrocatalytic reduction of CO2 was achieved.

A novel electrochemical sensor based on WO3 nanorods-decorated poly(sodium 4-styrenesulfonate) functionalized graphene nanocomposite modified electrode for detecting of puerarin

An electrochemical sensing platform was fabricated based on composition of poly(sodium 4-styrenesulfonate) (PSS), graphene (GN) and WO3 nanorods on glassy carbon electrode (GCE). The PSS-GN/WO3 nanocomposite significantly increased the oxidative activity of puerarin due to the individual merit and mutual effect of PSS-GN and WO3 nanorods which improved the performance of the electrochemical sensor with high sensitivity. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurements were used for the detection of puerarin. Under the optimal conditions, the oxidation peak currents of puerarin increased proportionally to the concentration within the range of 0.06–0.6μmolL−1 and 0.6–6.0μmolL−1, and the limit of detection was 0.04μmolL−1. The proposed modified electrode was highly sensitive and was successfully applied to determine puerarin in the pharmaceutical sample and human plasma with satisfactory recoveries. The as-prepared PSS-GN/WO3/GCE electrochemical sensor offers a feasible way for designing simpler, low-cost, no toxic and environment-friendly sensors based on WO3 nanorods.

Facile fabricating the polyoxometalates functionalized graphene nanocomposite applied in electrocatalytic reduction

The well dispersed and porous PMo12-rGO nanocomposite was synthesized via a chemical reduction method by the facile and economical reducing agent of thiourea. By optimizing the amount of reducing agent of thiourea, PMo12 was reduced to heteropoly blue, and then reacted with GO to assemble PMo12 clusters onto the rGO by the strong interaction between rGO and PMo12. The SEM, HTEM, FT-IR, UV–vis, XPS and Raman were performed to verify the structure of the PMo12-rGO nanocomposite. The as-prepared PMo12-rGO nanocomposite exhibits high stability and excellent electrocatalytic activity towards the reduction of nitrite and hydrogen peroxide compared with individual PMo12 catalysts, which could be mostly attributed to the synergistic effects of rGO and PMo12. The method is facile, economical and suitable for mass production and common POMs, which opens a new way to fabricate a wide range of hybrid materials using different type of polyoxometalates, and such as-prepared materials have potential applications in catalysis, electrochemisty and related fields.

Electrocatalytic properties of [FeFe]-hydrogenases models and visible-light-driven hydrogen evolution efficiency promotion with porphyrin functionalized graphene nanocomposite

Five tolyl-functionalized monophosphine substituted diiron complexes [Fe2(CO)5(L){μ-SC6H3(CH3)S}] (L=PPh3, 2; Ph2PCH2Ph, 3; Ph2PCH2CH2CH3, 4; Ph2P(2-C5H4N), 5; P(4-C6H4OCH3)3, 6), which could be regarded as the active site models of [FeFe]-hydrogenases, have been successfully synthesized from parent complex [Fe2(CO)6{μ-SC6H3(CH3)S}] (1). The influence of the different phosphine ligands on the reduction potentials of the models has been evaluated by cyclic voltammetry (CV). According to the result of the electrochemical analysis, complexes 1, 2 and 5 were chosen to carry out the photocatalytic experiments. Meanwhile, tetraphenylporphyrin (TPP) covalently functionalized graphene oxide (GO) nanocomposite (TPP-GO) and cystine were applied as the photosensitizer and the electron-donor respectively in the [FeFe]-hydrogenases bionic photocatalytic system. The result of light-driven hydrogen (H2) evolution in aqueous ethanol solution demonstrated that the efficiency of H2 production is affected by following factors: the participation of GO or cystine, the covalent functionalization of GO by TPP and the hetero-atom on the phosphine ligand substituent of [FeFe]-hydrogenases models. Ultraviolet-visible (UV–vis) absorption, fluorescence emission and time-resolved fluorescence were used to analyze and compare the efficiency of electron transferring in the process of photocatalytic H2 production. And a possible mechanism for the light-driven H2 evolution of the photocatalytic system containing TPP-GO was proposed.

Studies on Synthesis of Electrochemically Exfoliated Functionalized Graphene and Polylactic Acid/Ferric Phytate Functionalized Graphene Nanocomposites as New Fire Hazard Suppression Materials.

Practical application of functionalized graphene in polymeric nanocomposites is hampered by the lack of cost-effective and eco-friendly methods for its production. Here, we reported a facile and green electrochemical approach for preparing ferric phytate functionalized graphene (f-GNS) by simultaneously utilizing biobased phytic acid as electrolyte and modifier for the first time. Due to the presence of phytic acid, electrochemical exfoliation leads to low oxidized graphene sheets (a C/O ratio of 14.8) that are tens of micrometers large. Successful functionalization of graphene was confirmed by the appearance of phosphorus and iron peaks in the X-ray photoelectron spectrum. Further, high-performance polylactic acid/f-GNS nanocomposites are readily fabricated by a convenient masterbatch strategy. Notably, inclusion of well-dispersed f-GNS resulted in dramatic suppression on fire hazards of polylactic acid in terms of reduced peak heat-release rate (decreased by 40%), low CO yield, and formation of a high graphitized protective char layer. Moreover, obviously improvements in crystallization rate and thermal conductivities of polylactic acid nanocomposites were observed, highlighting its promising potential in practical application. This novel strategy toward the simultaneous exfoliation and functionalization for graphene demonstrates a simple yet very effective approach for fabricating graphene-based flame retardants.