Pendimethalin (PND) is a herbicide that is regarded to be possibly carcinogenic to humans and toxic to the environment. Herein, we fabricated a highly sensitive DNA biosensor based on ...ZIF-8/Co/rGO/C3N4 nanohybrid modification of a screen-printed carbon electrode (SPCE) to monitor PND in real samples. The layer-by-layer fabrication pathway was conducted to construct ZIF-8/Co/rGO/C3N4/ds-DNA/SPCE biosensor. The physicochemical characterization techniques confirmed the successful synthesis of ZIF-8/Co/rGO/C3N4 hybrid nanocomposite, as well as the appropriate modification of the SPCE surface. The utilization of ZIF-8/Co/rGO/C3N4 nanohybrid as a modifier was analyzed using. The electrochemical impedance spectroscopy results showed that the modified SPCE exhibited significantly lowered charge transfer resistance due to the enhancement of its electrical conductivity and facilitation of the transfer of charged particles. The proposed biosensor successfully quantified PND in a wide concentration range of 0.01–35 μM, with a limit of detection (LOD) value of 8.0 nM. The PND monitoring capability of the fabricated biosensor in real samples including rice, wheat, tap, and river water samples was verified with a recovery range of 98.2–105.6%. Moreover, to predict the interaction sites of PND herbicide with DNA, the molecular docking study was performed between the PND molecule and two sequence DNA fragments and confirmed the experimental findings. This research sets the stage for developing highly sensitive DNA biosensors that will be used to monitor and quantify toxic herbicides in real samples by fusing the advantages of nanohybrid structures with crucial knowledge from a molecular docking investigation.
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•Calf Thymus ds-DNA intercalation with pendimethalin herbicide.•Fast and sensitive monitoring of pendimethalin herbicide.•Bio-sensing approach confirmed with Docking investigation.
•Graphene oxide is used as a substrate for the in-situ growth of Ni(OH)(OCH3) nanosheets.•A NiS2@rGO hybrid is fabricated by sulfurizing the Ni(OH)(OCH3)@rGO intermediate.•Hierarchical NiS2@rGO is ...constructed from porous NiS2 nanosheets vertically anchored on rGO.•The charge storage mechanism in the NiS2@rGO electrode is controlled by electrolytes.•NiS2@rGO outperforms most NiS2-based materials in terms of rate and cycling performance.
In this work, graphene oxide is used as a substrate for the nucleation and growth of Ni(OH)(OCH3) during solvothermal synthesis. As a result, 2D Ni(OH)(OCH3) nanosheets are vertically anchored on 2D reduced graphene oxide (rGO) nanosheets, forming a Ni(OH)(OCH3)@rGO composite. Afterward, a NiS2@rGO hybrid is created by sulfurizing the Ni(OH)(OCH3)@rGO intermediate, which presents the same morphology as the intermediate but a porous structure of NiS2 nanosheets. The characteristic 2D porous structure of NiS2 nanosheets offers abundant active sites for charge storage, accelerates ion/electron transport, and buffers volume expansion. Meanwhile, rGO nanosheets can suppress the shuttle of polysulfides while also enhancing electrical conductivity. These factors in conjunction with the thin and robust ether-derived SEI are favorable to mechanical stability and rapid sodiation kinetics in the NiS2@rGO electrode in the ether-based electrolyte, thereby endowing it with exceptional rate capability (324 mA h g-1 at 5 A g-1) and a long lifespan (378 mA h g-1 over 1800 cycles at 1 A g-1). However, in the ester-based electrolyte, NiS2@rGO shows poor rate capability and cyclability. The kinetic analysis unveils the mechanism underlying the different electrochemical behavior in NiS2@rGO in the two electrolytes. More importantly, the NiS2@rGO electrode outperforms most NiS2-based materials reported in terms of rate and cycling performance owing to its unique hierarchical structure, making it a viable contender for anode materials in sodium-ion batteries. We also propose a novel M(OH)(OCH3)@rGO intermediate for the fabrication of transition-metal oxides/sulfides@rGO composites for energy storage and catalysis.
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The hybrid of pine dendritic BiVO4/reduced graphene oxide (rGO) has been synthesized firstly by one step hydrothermal method. The hybrid of BiVO4/13.0 wt% rGO not only enhances the response of BiVO4 ...and accelerates the response rate, but also shows good selectivity and stability to 10 ppm TEA at operating temperature of 180 °C. The enhancement can be attributed to the formation of heterojunction and the incorporating of rGO.
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•BiVO4/rGO hybrid has been synthesized firstly by facile one step hydrothermal method.•The hybrid to TEA exhibits higher response and shorter response time than BiVO4.•The improvement benefits from high surface area and rapid electron transfer of rGO.•The improvement also benefits from the formation of BiVO4/rGO p-n heterojunction.
The volatile gas of Triethylamine (TEA) can cause environment pollution and lead to the serious hurt of the human respiratory system. Therefore, it is necessary to detect low concentrations of TEA in our daily lives rapidly. The hybrid of pine dendritic BiVO4/reduced graphene oxide (rGO) has been synthesized firstly by one step hydrothermal process. The gas sensing tests show that the 13.0 wt% rGO hybrid not only exhibits high response of 5.9 and rapid response of 11.4 s, but also exclusive selectivity and long-term stability to 10 ppm of TEA at the operating temperature of 180 °C. The formation of heterojunction and the incoporation of rGO are responsible for the improving sensing properties of the hybrid to TEA, the former results in reduction of the electron depletion layer at interface in hybrid, while the latter enhances the specific surface of the hybrid and accelerates the transfer of electrons. The research is expected to have wide application in the development of composite based gas sensors made of rGO/metal oxide semiconductors.
Here, we report on the nitrogen doping of different graphene-based nanomaterials, namely two-dimensional (2D) graphene oxide (GO) and three-dimensional (3D) interconnected reduced graphene oxides ...(ICrGO), for energy storage. For N-doping, a facile hydrothermal approach was employed using ammonium fluoride (NH4F) as the precursor to synthesize 2D N-rGO and 3D N-ICrGO. The fabricated N-doped graphene-based materials were systematically studied using various surface characterization techniques and spectroscopic methods, revealing that the novel 3D N-ICrGO possessed thin transparent sheets and a highly interconnected graphene structure with moderate defect sites and that the N-doping of the graphene structure could be effectively controlled through the appropriate amount of NH4F within the precursor solutions. The energy storage performance of the 2D and 3D nanomaterials was determined using cyclic voltammetry and chronopotentiometry, showing that the novel N-ICrGO exhibited much higher specific capacitance in contrast to the N-rGO, ICrGO, and GO. The specific capacitance of N-ICrGO at 2.0 Ag−1 was determined to be 262 Fg−1, which was over 4.4 times higher than that of N-rGO (60 Fg−1). Furthermore, the N-ICrGO exhibited an excellent rate capability and high cycling stability, with <5% decay over 2400 cycles in symmetric capacitor, promising for advanced energy storage applications. This study demonstrates that the unique 3D structure of ICrGO and the N-doping greatly enhance the overall energy storage performance of graphene-based nanomaterials.
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•A facile approach for the N-doping of graphene based nanomaterials is demonstrated.•Effect of N-doping on 3D interconnected reduced graphene oxide is studied.•Doped N predominantly exists in pyrrolic N and increases the defect density.•N-doping and the 3D structure significantly enhance the capacitance and stability.
Thiol-functionalized reduced graphene oxide (TRGO) as a novel ion-to-electron transducing layer is firstly employed to develop durable solid-contact ion-selective electrodes (SC-ISEs) in this work. ...The performance of the sensors is evaluated by determining K+ and NO3− as an example of cation and anion. The covalent linkage of TRGO at golden electrode surface generates a stable transducing layer. No water films are observed in the proposed TRGO-based potassium (K+-TRGO-ISEs) and nitrate (NO3−-TRGO-ISEs) selective SC-ISEs. The resultant electrodes exhibit Nernstian responses (60.0 ± 0.4 mV/decade for K+-TRGO-ISEs and −60.0 ± 0.5 mV/decade for NO3−-TRGO-ISEs), low detection limits (2.5 × 10−6 M for K+-TRGO-ISEs and 4.0 × 10−6 M for NO3−-TRGO-ISEs) and good selectivity behavior. More importantly, the TRGO-based SC-ISEs display a much longer lifetime of 2 weeks than that of reduced graphene oxide-based SC-ISEs in continuous flowing solutions using a longer peristaltic pump. These improvements push TRGO a general and reliable transducer for the development of durable SC-ISEs.
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•TRGO acts as an efficient ion-to-electron transducing layer for durable SC-ISEs.•TRGO is covalently linked onto golden electrodes by a facile site-specific deposition.•The lifetime of TRGO-based SC-ISEs is much longer than that of rGO-based SC-ISEs.
•Porous network Fe2O3 effectively prepared from Fe3O4/rGO.•The porous network Fe2O3 exhibited good performance to ethanol gas.•The developed strategy can employed for preparation of other porous ...network metal oxide.
Nanoporous network metal oxides are potential candidates for various applications such as filtration, biomaterials devices, and sensing materials. The present work focused on the simple and scalable fabrication of the α-Fe2O3 nanoporous network for ethanol gas sensor using Fe3O4/reduced graphene oxide (rGO) as a precursor. The analyzed morphology and crystal structure indicated that the α-Fe2O3 nanoporous network was formed due to some factors during thermal procedures such as the phase transformation from magnetite to hematite, nanoparticle agglomeration, and combustion of rGO. The ethanol gas-sensing properties of the α-Fe2O3 nanoporous network were investigated. The response to 100ppm ethanol gas was as high as 9.5, while the cross-gas responses to 100ppm NH3, H2, and CO gases were all lower than 2.0. These values indicated a good selectivity of the sensors. Furthermore, the 90% response times to ethanol gas were less than 5s at 400°–450°C. The proposed strategy has potential in the preparation of other porous network metal oxides to achieve high-performance gas sensors.
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•A new strategy for efficient clean-up of viscous crude oil was proposed.•Wood sponge (F-rGO@WS) with longitudinal channels was fabricated from natural balsa wood.•F-rGO/WS possessed ...high hydrophobicity and quick electrothermal capability.•F-rGO/WS was able to efficiently separate viscous crude oil from water under a low voltage.
With the increasing occurrences of industrial oily wastewater emissions and crude oil spills, the deteriorated global environment and ecosystems have attracted a great deal of attention worldwide. Herein we report a highly hydrophobic balsa wood sponge wrapped with fluoroalkyl silane modified reduced graphene oxide (F-rGO@WS) for efficient clean-up of all kinds of oils including viscous crude oil from water. The F-rGO@WS possessed excellent water repellency with a water contact angle of 145°. Owing to high hydrophobicity and longitudinal channels, the F-rGO@WS was successfully applied for separating oil-water mixtures, and the separation efficiency reached 99.0%. Furthermore, the F-rGO@WS also possessed quick electrothermal capability and could be utilized as a filter to efficiently separate viscous crude oil from water by means of the generated Joule heat under a low voltage, and the separation rate was about 10 times higher than that without voltage. Our findings stand out a new tool to fabricate functional natural materials and exhibit great potential in practical applications such as water pollution control and clean-up of viscous crude oil.
Magnetic reduced graphene oxide/Fe3O4 (RGO/Fe3O4) composites were synthesized via chemical co-precipitation method. The RGO/Fe3O4 were characterized by field-emission transmission electron microscopy ...(FETEM), X-ray diffraction (XRD) and Raman spectrometry and magnetic property measurement system (MPMS), respectively. Polyalphaolefin (PAO) 6 with different contents of RGO/Fe3O4 was prepared by a dispersion process. The tribological properties of PAO 6 containing RGO/Fe3O4 were evaluated using a tribometer. Friction results indicated that RGO/Fe3O4 can significantly improve the tribological properties, especially anti-wear properties, of PAO 6. From the analysis results, RGO/Fe3O4 possibly repairs the worn surface by forming an effective tribofilm, which benefits from the synergistic effect of RGO and Fe3O4 from the RGO/Fe3O4 nanocomposites.
Schematic diagram of preparation process of PAO 6 with RGO/Fe3O4. Display omitted
•Magnetic RGO/Fe3O4 composites were synthesized.•RGO/Fe3O4 improved the tribological properties of PAO 6.•The role of RGO/Fe3O4 was ascribed to form tribofilm.
Increasing use and release of graphene nanomaterials and pharmaceutical and personal care products (PPCPs) in soil environment have polluted the environment and posed high ecological risks. However, ...little is understood about the interactive effects and mechanism of graphene on the behaviors of PPCPs in soil. In the present study, the effects of reduced graphene oxide nanomaterials (RGO) on the fate of triclosan in two typical soils (S1: silty loam; S2: silty clay loam) were investigated with 14C-triclosan, high-resolution mass spectrometry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations, and microbial community structure analysis. The results showed that RGO prolonged the half-life of triclosan by 23.6–51.3 %, but delayed the formation of transformed products such as methyl triclosan and dechlorinated dimer of triclosan in the two typical soils. Mineralization of triclosan to 14CO2 was inhibited by 48.2–79.3 % in 500 mg kg−1 RGO in comparison with that in the control, whereas the bound residue was 54.2–56.4 % greater than the control. RGO also reduced the relative abundances of triclosan-degrading bacteria (Pseudomonas and Sphingomonas) in soils. Compared to silty loam, RGO more effectively inhibited triclosan degradation in silty clay loam. Furthermore, the DFT calculations suggested a strong association of the adsorption of triclosan on RGO with the van der Waals forces and π-π interactions. These results revealed that RGO inhibited the transformation of 14C-triclosan in soil through strong adsorption and triclosan-degrading bacteria inhibition in soils. Therefore, the presence of RGO may potentially enhance persistence of triclosan in soil. Overall, our study provides valuable insights into the risk assessment of triclosan in the presence of GNs in soil environment.
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•RGO notably decreased triclosan mineralization while increased bound residue in soil.•RGO (500 mg kg−1) significantly prolonged the half-life of triclosan in soils.•RGO more effectively inhibited triclosan degradation in silty clay loam.•RGO delayed the formation of methyl triclosan and dechlorinated dimer of triclosan.•RGO increased triclosan persistence via adsorption and degrading bacteria inhibition.
Here, MoS2/rGO as a co-catalyst with Cu2O to suppress the recombination rate of the photogenerated charge carrier in Cu2O as well as to inhibit the photocorrosion and provide an electron rich ...environment to the system. The ternary composite shows higher photoactivity as compared with the bare one. The photoelectrochemical activity of the bare photocatalyst was 0.33 mA cm−2 while the photoelectrochemical activity of the ternary composite Cu2O-MoS2/rGO was 8.46 mA cm−2 which is 26 times higher photoactivity than the bare photocatalyst. Transient photocurrent response measurement provides the stability information of the photocatalysts.
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•Cost effective, non-toxic, and stable photo-catalyst Cu2O-MoS2/rGO.•Combination of MoS2/rGO with Cu2O makes more attractive towards PEC applications.•Photoelectrochemical activity of Cu2O-MoS2/rGO is 26 times higher than the bare Cu2O.•.Transient photocurrent response revealed the stability of the photocatalyst.
Solar to hydrogen conversion using photocatalyst is one of the most promising methods to get a pollution free and sustainable fuel. Most of the photocatalysts suffer with major problems like, charge recombination and photocorrosion, which diminishes their practical application. The need is to obtain a stable photocatalyst where the photocorrosion is inhibited. Cu2O has been used as a photocatalyst and it holds promise being non-toxic and abundantly available on earth. However, due to lower band edge of Cu2O, it gets oxidized easily and its high recombination rate of electron-hole pairs which lowers its activity. For the inhibition of the photocorrosion, there is a need of a passivation layer that protects the photocatalyst by blocking the unfavorable reaction which causes photocorrosion. Here, we have used MoS2/rGO as a co-catalyst with Cu2O to suppress the recombination rate of the photogenerated charge carrier in Cu2O as well as to inhibit the photocorrosion and provide an electron rich environment to the system. The ternary composite shows higher photoactivity as compared with the bare one. The photoelectrochemical activity of the bare photocatalyst was 0.33 mA cm−2 while the photoelectrochemical activity of the ternary composite Cu2O-MoS2/rGO was 8.46 mA cm−2 at 0.95 V. Transient photocurrent response measurement provides the stability information of the photocatalysts.
