Reduced Graphene Oxide Hybrid Film Research Articles

α-MnO2 Nanowires and Amino-Modified Reduced Graphene Oxide Hybrid Films for Constructing the Flexible High-Performance Symmetrical Supercapacitors

Graphene or its derivates are used as an electrode material for the fabrication of supercapacitors (SCs). However, graphene or its composites readily agglomerate or stack in water, which seriously imparts SC energy efficiency. Presently, we used a new composite using [Formula: see text]-MnO2 nanowires and nitrogen-doped reduced graphene oxide ([Formula: see text]-MnO2/NRGO) for the fabrication of electrodes required in symmetric SCs. Hydrothermally synthesized [Formula: see text]-MnO2 nanowires have a smooth surface, good dispersion, and a high length-to-width ratio. The formation of stable and densely networked structures and the synergy between NRGO and [Formula: see text]-MnO2 nanowires enable the [Formula: see text]-MnO2/NRGO film electrode to show a large area-specific capacitance (386.8[Formula: see text]mF[Formula: see text]cm[Formula: see text]) at 1[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] current density; the capacity retention is 62.4% when the current density increases from 1[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] to 10[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text]. The flexible and symmetrical [Formula: see text]-MnO2/NRGO SC was assembled using [Formula: see text]-MnO2/NRGO film electrodes in 1 M Na2SO4 electrolyte with a cellulose paper separator, has good capacitance retention (94%), excellent Coulombic efficiency (99%) after 3000 cycles, and high energy density (28.22[Formula: see text][Formula: see text]Wh[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text]) at 0.8[Formula: see text]mW[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] power density. The [Formula: see text]-MnO2 nanowires/NRGO hybrid film flexible and symmetrical SCs are characterized by high energy storage, good cycle life and Columbic efficiency, which offer promising applications in the portable and wearable electronics industry.

Nickel sulfide nanoworm network architecture as a binder-free high-performance non-enzymatic glucose sensor.

Nickel sulfide nanoworm (Ni3S2 NW) network architecture was directly grown on the poly (3,4-ethylenedioxythiophene)-reduced graphene oxide hybrid films (PEDOT-rGO HFs) modified on glassy carbon electrode (GCE), acting as a binder-free sensor for high-performance non-enzymatic glucose monitoring. The sensor exhibited the satisfactory sensitivity (2123μAmM-1cm-2), wide linear range (15~9105μM), low detection limit (0.48μM), and rapid response time (< 1.5s) at a potential of 0.5V (vs. SCE) in 0.1M NaOH and possessed good selectivity, reproducibility, and stability. The enhanced electrocatalytic activity of the sensor towards glucose oxidation was attributed to the particular morphology, satisfying hydrophilic nature, strong combination between Ni3S2 NWs, PEDOT-rGO, and bare GCE. Moreover, it can be used for assaying glucose in human serum samples without dilution, indicating potential for clinical diagnostic applications. Graphical abstract Nickel sulfide nanoworms (Ni3S2 NWs)/poly (3,4-ethylenedioxythiophene)-reduced graphene oxide hybrid films (PEDOT-rGO HFs) were used to construct a binder-free high-performance non-enzymatic glucose sensor with satisfactory sensitivity, wide linear range, low detection limit, good selectivity, amazing reproducibility, and stability.

Electrodeposition of Polyaniline/Three- Dimensional Reduced Graphene Oxide Hybrid Films for Detection of Ammonia Gas at Room Temperature

Reliable, sensitive and selective ammonia gas sensing at room temperature is very important for monitoring the environment for hazardous pollutants. In this study, ammonia (NH3) gas sensor is proposed based on polyaniline/three-dimensional reduced graphene oxide (PANI/3D-RGO) hybrid samples, which are loaded on glass substrates by electrochemical polymerization method. The PANI/3D-RGO hybrid samples with different weight percentages of 3D-RGO (weight% =0.05, 0.2, 0.5 and 1) are characterized by field emission-scanning electron microscopy, Fourier transform infrared and X-ray diffraction. The specific surface area is analyzed by the Brunauer-Emmett-Teller (BET) equation. The gas-sensing performances of the fabricated sensors indicate that PANI/3D-RGO (0.2wt. %) exhibits the best response for 50 ppm NH3 gas at room temperature, this sensor response to lower concentrations of NH3 (5ppm, 10 ppm and 25 ppm) too. The PANI/3D-RGO (0.2wt. %) hybrid sensor shows represent response values of about 3.72 and acceptable response and recovery times (98 s and 288 s) to 50 ppm NH3 which is about 4.27 fold higher than that of pure PANI in 50 ppm NH3 gas. The excellent sensing performance of the developed gas sensor can be attributed to the synergetic effects of PANI and 3D-RGO, $\pi -\pi $ interaction between the two components, efficient increase in hole-like carriers and substantial increase in active sites.

An Ag–TiO2–reduced graphene oxide hybrid film for electrochemical detection of 8-hydroxy-2′-deoxyguanosine as an oxidative DNA damage biomarker

Here, a notably sensitive and selective electrochemical sensor based on an Ag–TiO2–rGO hybrid nanomaterial modified SPE was developed for 8-OHdG detection, which is a significant DNA biomarker due to one of the main products of oxidative DNA damage.

Freestanding nitrogen-doped d-Ti3C2/reduced graphene oxide hybrid films for high performance supercapacitors

A facile method has been developed to prepare a freestanding binder-free nitrogen-doped delaminated-Ti3C2/reduced graphene oxide hybrid films for high-performance supercapacitor electrodes. This film exhibits a high specific capacitance of 247 F g−1 (∼445.2 F cm−3) at 1 A g−1 in 6 M KOH, which is still well maintained after 10000 cycles at 10 A g−1, demonstrating excellent long-term electrochemical stability. In addition, a flexible symmetric supercapacitor has been assembled with such films that delivers a maximum energy density of 15.7 W h kg−1 (at 309.3 W kg−1) and a power density of 3738.7 W kg−1 (at 11.1 W h kg−1) in PVA/H2SO4 gel. This impressive electrochemical performance can be attributed to the enhanced conductivity and high pseudocapacitance offered by the heteroatoms of nitrogen and the alleviated self-restacking of MXene layers by the introduction of reduced graphene oxide nanosheets.

Electrochemical Detection of Hg(II) in Environmental Water Samples Based on Multiwalled Carbon Nanotube–Reduced Graphene Oxide Hybrid Film

In this work, we describe the fabrication of an electrochemical sensor for the detection of Hg2+in various water samples. The electrochemical sensor is fabricated on an indium tin oxide (ITO) modified with multi–walled carbon nanotubes (MWCNT) and reduced graphene oxide (RGO) hybrid film. The MWCNT was firstly dispersed using graphene oxide (GO) as dispersant. After coating on the ITO, the GO was then electrochemically reduced to RGO. The obtained thin film was characterized by scanning electron microscope (SEM), FTIR, Raman spectroscopy and 3D optical surface profiler. Cyclic voltammetry and differential pulse voltammetry were employed to investigate the electrocatalytic performance towards the Hg2+ oxidation. Under optimum conditions, the proposed sensor showed a wider linear range at Hg(II) concentrations of 0.05–150 nM. The limit of detection was calculated to be 0.05 nM.

3D Porous MXene (Ti3C2)/Reduced Graphene Oxide Hybrid Films for Advanced Lithium Storage.

MXenes, as a new family of 2D materials, can be used as film electrodes in energy storage devices because of their hydrophilic surface, metallic conductivity, and rich surface chemistries. However, the poor ion transport of MXene film electrodes causes a great loss of surface reactivity, which significantly inhibits the full exploitation of the potential of MXene-based materials. To solve this issue, we report a facile electrolyte-induced self-assembly method to construct a 3D porous structure in the MXene-rGO hybrid film, which effectively facilitates rapid diffusion and transport of electrolyte ions in the film electrode while still maintaining high electrical conductivity. When the hybrid film is employed as electrode materials for lithium-ion batteries, it exhibits high specific capacity of 335.5 mA h g-1 at 0.05 A g-1 and good rate capability of 30% capacitance retention at 4 A g-1. Additionally, the film electrode exhibits excellent cycling stability without capacity decay after 1000 cycles under high rates (1 A g-1) owing to its stable structure. Furthermore, the electrochemical analysis also demonstrates that the novel 3D porous microstructure plays an important role in the fast reaction kinetics and high capacity of the MXene-rGO hybrid film electrode. This work may provide a new strategy to solve the issues related to poor ionic transport in MXene-based film electrodes.

Facile fabrication of NiS and a reduced graphene oxide hybrid film for nonenzymatic detection of glucose

In the present study, nickel sulfide (NiS) decorated reduced graphene oxide was synthesized by a facile one-step hydrothermal approach.

Fabrication of cobalt porphyrin. Electrochemically reduced graphene oxide hybrid films for electrocatalytic hydrogen evolution in aqueous solution.

Here we report on an experimental study of an electrocatalyst for the hydrogen evolution reaction (HER) based on cobalt porphyrin and electrochemically reduced graphene oxide (ERGO) functional multilayer films, which are prepared by the alternating layer-by-layer (LBL) assembly of negatively charged graphene oxide (GO) and positively charged [tetrakis (N-methylpyridyl) porphyrinato] cobalt (CoTMPyP) in combination with an electrochemical reduction procedure. The resulting [ERGO@CoTMPyP]n multilayer films display relatively high electrocatalytic activity and superior stability toward HER in alkaline media. Electrochemical studies indicate that CoTMPyP in the multilayer films is the active catalyst for the reduction of protons to dihydrogen.