Introduction Of Graphene Oxide Research Articles

Experimental study on the temperature-sensitive behavior of poly-n-isopropylacrylamide/graphene oxide composites and the flexible conductive cotton fabrics

This work focused on the development and characterization of poly-n-isopropylacrylamide/graphene oxide composite (PNIPAM-GO) which was prepared by in situ free radical polymerization of n-isopropylacrylamide and graphene oxide (GO). It was then compounded on cotton fabrics by dip-drying layer group method to prepare PNIPAM-GO/cotton fabrics, which were further reduced by hydrazine hydrate to obtain PNIPAM-rGO/cotton conductive fabrics. The conductivity of flexible conductive fabrics and performance of PNIPAM-GO composite were studied by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results show that PNIPAM-GO composites have reversible temperature-sensitive response, the lower critical solution temperature (LCST) of PNIPAM-GO composites increased with the introduction of GO. With increasing of dip-drying cycles, the resistance value of PNIPAM-rGO/cotton fabrics decreased, which decreased from 908.3 KΩ with 5 dip-drying cycle processes to 162.5 KΩ with 15 dip-drying cycle processes at 25 °C. Besides, PNIPAM-rGO/cotton fabrics have temperature-sensitive conductivity, the resistance value decreased when testing temperature above LCST. The results also show that the resistance value changed reversibly with the changing of testing temperature above or below the LCST of PNIPAM-GO. Therefore, PNIPAM-rGO/cotton fabrics have potential development in flexible conductive materials in temperature control valve.

Photocatalytic Anaerobic Oxidation of Aromatic Alcohols Coupled With H2 Production Over CsPbBr3/GO-Pt Catalysts.

Metal halide perovskites (MHPs) have been widely investigated for various photocatalytic applications. However, the dual-functional reaction system integrated selective organic oxidation with H2 production over MHPs is rarely reported. Here, we demonstrate for the first time the selective oxidation of aromatic alcohols to aldehydes integrated with hydrogen (H2) evolution over Pt-decorated CsPbBr3. Especially, the functionalization of CsPbBr3 with graphene oxide (GO) further improves the photoactivity of the perovskite catalyst. The optimal amount of CsPbBr3/GO-Pt exhibits an H2 evolution rate of 1,060 μmol g−1 h−1 along with high selectivity (>99%) for benzyl aldehyde generation (1,050 μmol g−1 h−1) under visible light (λ > 400 nm), which is about five times higher than the CsPbBr3-Pt sample. The enhanced activity has been ascribed to two effects induced by the introduction of GO: 1) GO displays a structure-directing role, decreasing the particle size of CsPbBr3 and 2) GO and Pt act as electron reservoirs, extracting the photogenerated electrons and prohibiting the recombination of the electron–hole pairs. This study opens new avenues to utilize metal halide perovskites as dual-functional photocatalysts to perform selective organic transformations and solar fuel production.

High Performance and Self-Humidifying of Novel Cross-Linked and Nanocomposite Proton Exchange Membranes Based on Sulfonated Polysulfone.

The introduction of inorganic additive or nanoparticles into fluorine-free proton exchange membranes (PEMs) can improve proton conductivity and have considerable effects on the performance of polymer electrolyte membrane fuel cells. Based on the sol–gel method and in situ polycondensation, novel cross-linked PEM and nanocomposite PEMs based on a sulfonated polysulfone (SPSU) matrix were prepared by introducing graphene oxide (GO) polymeric brushes and incorporating Pt-TiO2 nanoparticles into an SPSU matrix, respectively. The results showed that the incorporation of Pt-TiO2 nanoparticles could obviously enhance self-humidifying and thermal stability. In addition, GO polymer brushes fixed on polymeric PEM by forming a cross-linked network structure could not only solve the leakage of inorganic additives during use and compatibility problem with organic polymers, but also significantly improve proton conductivity and reduce methanol permeability of the nanocomposite PEM. Proton conductivity, water uptake and methanol permeability of the nanocomposite PEM can be up to 6.93 mS cm−1, 46.58% and be as low as 1.4157 × 10−6 cm2 s−1, respectively, which represent increases of about 70%, about 22% and a decrease of about 40%, respectively, compared with that of primary SPSU. Therefore, the synergic action of the covalent cross-linking, GO polymer brush and nanoparticles can significantly and simultaneously improve the overall performance of the composite PEM.

Synthesis and characterization of wood flour modified by graphene oxide for reinforcement applications

Abstract The performance of thermoplastic polyurethane (TPU) reinforced with natural fibers can be tailored through a suitable choice of the fibers nature or the type of surface treatment applied to them. The present work deals with the improvement of the interfacial properties of natural fibers, namely wood flour (WF) by the introduction of graphene oxide (GO), which may easily disperse on the WF surface to provide hybrid fibers (WF-GO). The latter were then used as reinforcement of a TPU matrix at different ratios of 1, 3 and 5 wt%. The different samples were characterized by FTIR and RAMAN spectroscopies, XRD, SEM and TGA to confirm the structure, morphology and the thermal stability of the prepared hybrid fibers as well as their composites (TPU/WF-GO). SEM micrographs revealed that the surface treatment applied to WF, the distribution of GO sheets on the fiber interface, and the dispersion of (WF-GO) on the polymer matrix were successfully carried out. The thermal stability of the TPU-base composites increased with the increase of WF-GO content from 325 °C for the pure TPU matrix to 343 °C for the composite reinforced by 5% of (WF-GO). In addition, the results confirmed that the incorporation of GO into WF led to a significant improvement in the mechanical properties of the TPU-based composites, with an improvement in strength from 10.9 MPa to 19 MPa.

Interfacial reinforcement of composites by the electrostatic self-assembly of graphene oxide and NH3 plasma-treated carbon fiber

The introduction of graphene oxide (GO) on the surface of carbon fiber (CF) is considered an effective strategy to modulate the structure and properties of the fiber/matrix interface in CF reinforced polymer composites. However, the tensile strength of fibers often decreases due to the etching effect during treatment. In this study, a new method was proposed to graft GO onto fiber surfaces by electrostatic self-assembly. The results showed that NH2 grafted onto CF through NH3 plasma treatment caused CF and GO to have opposite charges in deionized water; subsequently, they self-assembled to form CF@GO due to the electrostatic force. The tensile strength of CF@GO was 31.23% greater than that of pristine CF, which may be because the different sizes of GO repaired the surface defects on the CF with its multilayer restoration structure. The CF showed a noticeable improvement in surface wettability due to the GO coating. Moreover, the interfacial properties were significantly improved, with the interfacial shear strength (IFSS) of CF@GO increasing to 81.31 MPa, which was about twice that of unmodified CF. This work provides a promising strategy for nondestructive grafting nanoparticles on CF to build a strong interface in CF composites.

Construction of core-shell Fe3O4@GO-CoPc photo-Fenton catalyst for superior removal of tetracycline: The role of GO in promotion of H2O2 to •OH conversion

A novel core-shell structured Fe3O4@GO-CoPc magnetic catalyst, which is with magnetite (Fe3O4) as the core, graphene oxide (GO) as the interlayer and cobalt-phthalocyanine (CoPc) as the shell, was successfully prepared and used as a heterogeneous photo-Fenton catalyst for tetracycline (TC) degradation in this work. The core-shell structure of the catalyst was confirmed by XRD, FTIR, SEM and TEM. BET and magnetic hysteresis loops measurements indicated that Fe3O4@GO-CoPc catalyst owned large specific surface area and could be easily recovered under an external magnetic field. Meanwhile, the experimental results of TC degradation demonstrated that the photo-Fenton efficiency of Fe3O4@GO-CoPc was excellent. When the reaction time was 120 min, TC could be degraded almost completely in the photo-Fenton system with Fe3O4@GO-CoPc. The high photo-Fenton catalytic activity of Fe3O4@GO-CoPc could be resulted from the effective transfer of photo-generated electrons between CoPc and Fe3O4 by GO. Moreover, the main reaction species, •OH, O2•-, 1O2 and h+, were verified by the analysis of active species in this system. Finally, the mechanism analyses and quantitative analysis results of active species indicated that the introduction of GO accelerated the cycle between Fe(II) and Fe(III) as well as improved the effective utilization of H2O2 (the efficiency of conversion of H2O2 to •OH).

Optical properties and photothermal conversion performances of graphene based nanofluids

• Single-layer graphene and GO nanofluids were designed for solar thermal application. • Uniform temperature distribution is achieved in nanofluids based on the RI-DASC mode. • The photothermal conversion efficiency of SLG is 49.13% at 100 ppm in the RI-DASC mode. • The photothermal conversion efficiency of GO reaches 46.26% at 100 ppm in the RI-DASC mode. Direct absorption solar collectors (DASC) are extremely attractive in solar energy utilization. In this paper, starting from these two aspects, graphene-based nanofluids, including single-layer graphene (SLG) and graphene oxide (GO), are prepared to enhance solar absorption and photothermal conversion performance. The influence of nanofluids' concentration and two different irradiation modes: traditional DASC and reverse radiation DASC (RI-DASC) on the photothermal conversion performance of graphene-based nanofluids has been studied. The addition of a small amount of SLG or GO significantly improves the photothermal conversion efficiency of base fluid, and it increases along with the increase of the concentration. Furthermore, the RI-DASC mode has a more uniform thermal field distribution and the higher photothermal conversion efficiency than the DASC mode. In DASC mode, the photothermal conversion efficiency of pure water is 17.00%. By changing the irradiation mode, the introduction of GO and SLG nanofluids (100 ppm) increased the photothermal conversion efficiency by about 172% and 189%, reaching 46.26% and 49.13%. According to the photothermal-thermoelectric conversion experiment, the positive correlation between the output power of the TE module and the heating state of the nanofluid makes it possible to adjust the nanofluid in real-time. This work presents a feasible way to enhance solar energy absorption and improve the photothermal conversion efficiency of nanofluids for DASC.

Bacterial cellulose nanofibrous ion imprinted aerogel for highly efficient recognition and adsorption of Dy(III)

The highly selective recovery of Dy(III) from used rare earth products has high environmental and economic benefits. In this paper, biocompatible bacterial cellulose with a unique 3D network structure was used as the basic structure, graphene oxide and polyethylene glycol were introduced to increase the adsorption capacity, and the ion imprinting technology was used to prepare a green aerogel that could adsorb dysprosium ions with a high selectivity. The various properties of aerogels were characterized by SEM, FT-IR and BET. Experiments proved that the introduction of graphene oxide and polyethylene glycol brought a higher stability and repeatability to aerogel, and the introduction of a large number of carboxyl groups also promoted the effective coordination of aerogel with dysprosium. Adsorption experiments showed that I-GO-OBC-pDA-PEG aerogel could effectively adsorb dysprosium, and its maximum adsorption capacity for Dy(III) was 49.904 mg g−1, and its maximum adsorption capacity was 10 mg g−1 higher than that of the non-imprinted aerogel, which was a good proof of the effectiveness of the ion imprinting technology. The repeatability test showed that after five adsorption-desorption cycles, the adsorption capacity of the imprinted aerogel was maintained at about 80% of the maximum adsorption capacity. All results showed that I-GO-OBC-pDA-PEG aerogel could efficiently recover dysprosium ions.

Improved interfacial performance of carbon fiber/polyetherimide composites by polyetherimide and modified graphene oxide complex emulsion type sizing agent

In the field of interfacial enhancement of composite, sizing method has attracted extensive attention. In this research, a new complex emulsion type sizing agent containing polyetherimide (PEI) and covalently chemical functionalized graphene oxide (GO) was first proposed to further improve the interfacial adhesion of carbon fiber (CF)/PEI composites, adapt to the high processing temperature, and overcome the shortcomings of the solution type sizing agent. The emulsion was prepared by the emulsion/solvent evaporation method. In order to avoid the agglomeration of nanomaterials on CF surface, the monomer and polymer structure of PEI was used to functionalize GO, so as to achieve better compatibility and dispersion of GO in PEI. The physicochemical state of CF surface was characterized and the successful introduction of GO was verified. The microbond test revealed that the introduction of GO further improved the IFSS compared with only PEI sizing. When GO grafted with PEI was used as the main component of the sizing agent, the IFSS reached the largest with an increasement of 55.96%. The mechanism of interfacial reinforcement was proposed. Increased ability of mechanical interlocking, the mutual solubility between PEI molecular chains, and the improvement in wettability may be beneficial to the interfacial strength. This mild and effective modification method provided theoretical guidance for the interfacial enhancement of composites and was expected to be applied in industrial production.

Enhancement of heat transfer using nano fluids in a mini-radiator

Nano fluids play a vital role in many industrial applications. Researchers are working on fabrication of nanofluids worldwide to enhance the applicability of these materials. Since a lot of research is going in the field of nanofluids. We can ensure that the nanofluids are the fluids of the future. Nanofluids have a wide range of applications in electronics cooling, building cooling, and chemical industries, among others. Also due to the advancements in the field of the nanofluids, various types of hybrids nanofluids are coming into the market. In comparison to graphene oxide particles, metals and metallic oxide nanoparticles have been widely explored for heat transfer applications. In this study, the impact of introducing graphene oxide (GO) nanoparticles and super graphene (SG) nanoparticles to a normal hot water (hybrid nanofluids) - on the performance of a mini radiator is investigated. The influence of heated fluid discharge, air speed, and nanoparticle volume concentration on performance metrics such as Nusselt number (Nu), pressure drop, and friction factor (ff) is investigated in depth. At 0.4 vol% of hybrid nanofluids (HN), the Nusselt number increases to a maximum of 5.62 times. The results show a considerable improvement in the mini radiator’s performance, both in terms of efficacy and pressure drop. At a volume concentration of 0.4 vol% GO, the study found a maximum improvement in efficacy and reduction in pressure drop. Functionalized graphene has a lot of potential for improving the performance of mini radiator and/or reducing their size.

Influence of graphene oxide on asphaltene nanoaggregates

Asphaltenes are a group of exotic hydrocarbons found in bitumen and other forms of heavy crude oil derivatives. These hydrocarbons, with elusive chemistry, give crude oil derivatives (CODs), such as bitumen, its characteristic properties. In bitumen, they form stable aggregates by interacting with other molecules, called asphaltene aggregates. Attempts have been made to enhance bitumen with nanoparticles, like graphene derivatives. Such studies have been successful in displaying the enhanceability of bitumen, but no studies have been directly focused on how the structural stability of asphaltene aggregates present in bitumen is affected by the incorporation of nanoparticles. The phase stability of the asphaltene aggregates is a pertinent question, which is often ignored. In this study, we investigate the physical impact of incorporating graphitic nanoparticles on the structure of bitumen. For this, we utilise graphene oxide (GO). GO is a form of polyaromatic nanoparticle with a similar structure to asphaltenes, such that both have molecular defects induced by heteroatoms. We have experimentally investigated the structural stability of the asphaltenes, using XPS, XRD and SEM-EDX to elucidate the interaction between asphaltenes and GO, and its implications for the stability of bitumen used for e.g., the surface layer of roads. In roads, asphaltene aggregates exist as stable structures, until GO has been introduced. The experimental results show that the introduction of GO initiates destabilisation of the asphaltene aggregates, and we discuss the destabilisation mechanism in this paper. Thereby, we conclude that counter intuitively, the introduction of graphene or GO has a negative impact on the structure of bitumen, thus hindering any functional enhancements to bituminous roads.

Ultrafast Response Optical Microfiber Interferometric VOC Sensor Based on Evanescent Field Interaction with ZIF‐8/Graphene Oxide Nanocoating

AbstractIncorporating nanomaterials into photonic device to enhance light–matter interaction is a promising method to enhance photonic sensing, and investigating the interaction of nanomaterials with photonic devices is essential for evanescent field‐based photonic devices. In this study, the light–matter interaction of nanomaterial‐photonic devices is investigated via in situ synthesis of multilayer zeolitic imidazolate framework‐8 (ZIF‐8) nanoparticles on a graphene oxide (GO) premodified optical fiber. The introduction of GO successfully refines the weak adhesion of ZIF‐8 on the optical microfiber, which aids the synthesis of highly uniform morphology. Based on the evanescent field change during the growth process of ZIF‐8 on the optical microfiber, the optical properties of ZIF‐8 are obtained through experiment and simulation. Ethanol is used to verify the capability of the sensing platform, and a concentration specific response with high sensor response at room temperature and low limit detection (5.26 ppm) is demonstrated, which matches the theoretical results. The incorporation of the GO/ZIF‐8 multilayer fiber sensor leads to ultrafast sensor response (118 ms), resulting from the high specific surface area and porous structure. The obtained sensor provides a guideline for metal‐organic frameworks (MOFs) coated photonic devices with potential industrial applications and environmental benefits.

GO/HTPB composite liner for anti-migration of small molecules

Hydroxyl-terminated polybutadiene/toluene diisocyanate (HTPB/TDI) system is widely used in composite solid propellants. The migrations of plasticizers and water molecules from solid propellants and surrounding environment to the inhibitor have always been the important issues. This study focuses on the preparation, characterization and anti-migration behavior of graphene oxide (GO)/HTPB nanocomposite liner. The GO/HTPB (GH) composite liners affect the migration of small molecules through a tighter cross-linked structure and weakening function of small molecule adsorption. The anti-migration performance of the liner at different temperatures was analyzed, and the influence of the added amount of GO on the anti-migration performance and adhesion performance was also systematically studied. The overall performance of the liner is optimized when the amount of GO filler is 0.3 wt%. After adding 0.3 wt% GO, the concentration of dioctyl sebacate (DOS) migrated into the liner is decreased by 23.28%, and the concentration of water molecules is decreased by 51.89%, indicating that the introduction of GO can significantly improve the anti-migration performance of the liner. In addition, the bond strength is greatly increased from 0.25 MPa to 0.95 MPa, which meets the application requirements of the current propellant system. This research provides an important way for the preparation of structure-function synergistic anti-migration composite liners.

Preparation of Graphene Oxide-loaded Nickel with Excellent Antibacterial Property by Magnetic Field-Assisted Scanning Jet Electrodeposition.

Graphene oxide (GO) is recognized as a promising antibacterial material that is expected to be used to prepare a new generation of high-efficiency antibacterial coatings. The propensity of GO to agglomeration makes it difficult to apply it effectively. A new method of preparing GO-loaded nickel (GNC) with excellent antibacterial property is proposed in this paper. In this work, GNC was prepared on a titanium sheet by magnetic field-assisted scanning jet electrodeposition. The massive introduction of GO on the coating was proven by energy disperse spectroscopy and Raman spectroscopy. The antibacterial performance of GNC was proven by agar plate assessment and cell living/dead staining. The detection of intracellular reactive oxygen species (ROS) and the concentration of nickel ions, indicate that the antibacterial property of GNC are not entirely derived from the nickel ions released by the coating and the intracellular ROS induced by nickel ions, but rather are due to the synergistic effect of nickel ions and GO.

High temperature properties of graphene oxide modified metakaolin based geopolymer paste

Geopolymer is considered as a new generation of green building materials. However, metakaolin (MK) based geopolymers are prone to burst and lose mechanical strength after high temperature exposures. The high temperature gradient between the inner parts and outer surfaces of geopolymer is the main factor affecting its properties. In this work, the introduction of graphene oxide (GO) provides feasibility for improving the thermal stability of geopolymer. The optimal dispersion conditions of GO were determined and the prepared GO modified geopolymer was exposed to high temperature. The high temperature properties of geopolymer were described by measuring its surface morphology, compressive strength and linear shrinkage. The microstructure and phase transition of GO-MK geopolymer were explored by XRD, SEM, FT-IR and TG tests, and finally, the strengthening mechanism of GO was discussed. The results show that methanol is beneficial for stable dispersion of GO in alkaline environment. The addition of well-dispersed GO can accelerate the geopolymerization process and effectively prevent the development of cracks caused by thermal stress, thus improving the thermal stability of geopolymer. After high temperature exposure, the residual strength of the GO modified geopolymer was significantly higher than that of the control sample. The compressive strength of the modified geopolymer could reach to 25 MPa at 600 °C, which is 25% higher than that of the unmodified sample.

Robust Biomimetic Nacreous Aramid Nanofiber Composite Films with Ultrahigh Thermal Conductivity by Introducing Graphene Oxide and Edge-Hydroxylated Boron Nitride Nanosheet.

Dielectric materials with excellent thermally conductive and mechanical properties can enable disruptive performance enhancement in the areas of advanced electronics and high-power devices. However, simultaneously achieving high thermal conductivity and mechanical strength for a single material remains a challenge. Herein, we report a new strategy for preparing mechanically strong and thermally conductive composite films by combining aramid nanofibers (ANFs) with graphene oxide (GO) and edge-hydroxylated boron nitride nanosheet (BNNS-OH) via a vacuum-assisted filtration and hot-pressing technique. The obtained ANF/GO/BNNS film exhibits an ultrahigh in-plane thermal conductivity of 33.4 Wm−1 K−1 at the loading of 10 wt.% GO and 50 wt.% BNNS-OH, which is 2080% higher than that of pure ANF film. The exceptional thermal conductivity results from the biomimetic nacreous “brick-and-mortar” layered structure of the composite film, in which favorable contacting and overlapping between the BNNS-OH and GO is generated, resulting in tightly packed thermal conduction networks. In addition, an outstanding tensile strength of 93.3 MPa is achieved for the composite film, owing to the special biomimetic nacreous structure as well as the strong π−π interactions and extensive hydrogen bonding between the GO and ANFs framework. Meanwhile, the obtained composite film displays excellent thermostability (Td = 555 °C, Tg > 400 °C) and electrical insulation (4.2 × 1014 Ω·cm). We believe that these findings shed some light on the design and fabrication of multifunctional materials for thermal management applications.

Graphene oxide-assisted Co-sintering synthesis of carbon nanotubes with enhanced electromagnetic wave absorption performance

Based on thermal reaction of small organic precursors and solid phase sintering process, 0D CoFe nanoparticle@1D carbon nanotube@2D rGO (reduced graphene oxide) sheet (CoFe-CNT-rGO) electromagnetic wave absorbing composite materials with hierarchical structure are prepared. In the reaction system, citric acid and urea are used as precursors to be adsorbed on the surface of the active alloy particles and gradually form carbon nanotubes. Introduction of graphene oxide (GO) provides “flexible substrate” with oxygen containing groups, which can generate conjugation between iron(III)/cobalt(II) complexes and graphene oxide. Thus, the adjacent molecules can orientate to promote the carbon nanotube growth. In situ template-free process in this research gives an effective and low-cost method for large scale preparation of carbon nanotubes. The prepared CoFe-CNT-rGO hierarchical composite exhibits outstanding electromagnetic wave absorbing ability with the lowest reflection loss reaching −56 dB. Synergistic effect of 2D dielectric carbon sheet, 1D carbon nanotube, 0D CoFe nanoparticles and their corresponding hierarchical structures are responsible for the enhanced electromagnetic wave absorption performance.

Enhancing bioenergy production with carbon capture of microalgae by ultraviolet spectrum conversion via graphene oxide quantum dots

Microalgae play an important role in carbon sequestration by converting solar energy into biomass as an energy reserve. The conversion efficiency is often limited by light absorbed in the chloroplast. It is of great potential to enhance the photosynthesis capability by improving susceptibility of the light absorption by microalgae. Carbon-based quantum dots (QDs) are promising candidates for spectrum conversion, exhibiting remarkable biocompatibility, excellent water solubility, and customizable flexibility. Herein, we introduced graphene oxide quantum dots (GOQDs) with a blue light (465 nm) emission after ultraviolet (380 nm) excitation into the microalgae growth media. It is demonstrated that the ultraviolet light was effectively absorbed and utilized by the chlorophyll in the GOQDs-Chlorella pyrenoidosa system, resulting in a significantly increased photosynthetic activity. Moreover, a 20% improvement in carbon dioxide fixation and a 34% increase in bioenergy accumulation was found in the system. We further examined the microalgae metabolic pathways to reveal the biological response mechanism with GOQDs. Results verified that the GOQDs facilitated photosystem II (PSII) energy transfer to improve the photosynthesis of microalgae and upregulated the metabolites of lipid biosynthesis, resulting in a higher biomass and lipid content. This work suggested that using GOQDs as a promising approach for to improve the photosynthetic efficiency of microalgae, as well as a great potential for enhancing carbon capture and bioenergy production, especially in the environments with higher solar ultraviolet irradiation.

Emergent hierarchical porosity by ZIF-8/GO nanocomposite increases oxygen electroreduction activity of Pt nanoparticles

Hierarchically porous materials are promising as catalyst supports in fuel cells and batteries as they increase overall mass transfer and active site density. In this work, a hierarchically porous catalyst support for oxygen reduction reaction (ORR) in acidic media has been developed by a bottom-up approach. Graphene oxide (GO) was introduced during synthesis conditions of zeolitic imidazolate framework-8 (ZIF-8) to produce hybrid material of ZIF-8/GO. Successful nanocomposite formation was realized by preserved crystallinity and chemical interaction between species as revealed by X-ray diffraction and Fourier transform infrared spectroscopy. Introduction of GO and pyrolysis of resulting hybrid structure causes emergence of disordered meso/macropores with an accompanying increase in pore volume as revealed by N2 sorption experiments. Pt nanoparticle deposition on pyrolyzed hybrid material by polyol method results in electrocatalyst Pt/NC-1, which shows greatly improved mass activity (182 vs 86 A g−1Pt) and specific activity (467 vs 186 μA g−1Pt) at 0.8 V for ORR against reference electrocatalyst Pt/r-GO and improved specific activity against Pt/C.

Evaluation of solvent transport and cure characteristics of chlorobutyl rubber graphene oxide nanocomposites

Chlorobutyl rubber (CIIR) is a significant type of synthetic rubber with interesting properties and thereby finds applications in numerous filed. Insertion of nanofillers like organo clay, carbon nanotubes, graphene etc. into CIIR matrix reduces the permeability which is useful for the synthesis of membranes with less solvent and gas permeation. In this work, introduction of graphene oxide (GO) improved the cure characteristics of CIIR matrix. Bound rubber content also improved with increasing filler concentration. Moreover, a reduction in mol percentage of uptake was observed with increase in temperature. This study clearly shows the ability of GO in CIIR matrix to prevent the solvent transport through the polymer, which opens its application in chemical protective clothing.