Boron From Net Charge Acceptor to Donor and Its Effect on Hydrogen Uptake by Novel Mg-B-electrochemically Synthesized Reduced Graphene Oxide

Abstract Hydrogen uptake (H-uptake) is studied in ball milled Mg-B-electrochemically synthesized reduced graphene oxide (erGO) nanocomposites at PH2≈15 bar, ~320 ℃. B/C (weight ratio): 0, ~0.09, ~0.36, ~0.90 are synthesized maintaining erGO≈10wt %. B occupies octahedral interstices within Mg unit cell - revealed by electron density maps. Persistent charge donations from Mg and B to C appear as Mg-C (~283.2 eV), B-C (~283.3-283.9 eV) interactions in C-1s core X-ray photoelectron spectrometry (XPS) at all B/C. At B/C>0.09, charge reception by B from Mg yields Mg-B interaction (51.3 eV, Mg-2p XPS). This net charge acceptor role of B does not alter Mg unit cell size significantly. Despite charge donation to both C and B, the Mg charge is <+2, resulting in long incubation times (>5 h) at B/C>0.09. In B/C≈0.09, C-2p π→π* transition (~290 eV, C-1s XPS) is also seen. Absence of Mg-B interaction renders B a charge donor, resulting in Mg-B repulsion and Mg unit cell expansion. Mg-C peak shift to lower binding energies (C-1s XPS), decreases incubation time to 2.25 h and increases H-uptake kinetics. Various atomic interactions influence the reduction of incubation time in H-uptake and increase its kinetics in the order: (Mg→C; B→C)B/C≈0.09 > (Mg→C)B/C=0 > (ternary Mg→B→C)B/C>0.09.

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Boron from net charge acceptor to donor and its effect on hydrogen uptake by novel Mg-B-electrochemically synthesized reduced graphene oxide

Scientific Reports ◽

10.1038/s41598-021-90531-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marla V. V. Satya Aditya ◽

Srikanta Panda ◽

Sankara Sarma V. Tatiparti

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Incubation Time ◽

Photoelectron Spectroscopy ◽

Weight Ratio ◽

Hydrogen Uptake ◽

Binding Energies ◽

Unit Cell ◽

Net Charge ◽

Reduced Graphene

AbstractHydrogen uptake (H-uptake) is studied in ball milled Mg-B-electrochemically synthesized reduced graphene oxide (erGO) nanocomposites at PH2 ≈ 15 bar, ~ 320 °C. B/C (weight ratio): 0, ~ 0.09, ~ 0.36, ~ 0.90 are synthesized maintaining erGO≈10wt %. B occupies octahedral interstices within Mg unit cell—revealed by electron density maps. Persistent charge donations from Mg and B to C appear as Mg-C (~ 283.2 eV), B-C (~ 283.3–283.9 eV) interactions in C-1s core X-ray photoelectron spectroscopy (XPS) at all B/C. At B/C > 0.09, charge reception by B from Mg yields Mg-B interaction. This net charge acceptor role of B renders it electron-rich and does not alter Mg unit cell size significantly. Despite charge donation to both C and B, the Mg charge is < + 2, resulting in long incubation times (> 5 h) at B/C > 0.09. At B/C≈0.09 the minimal Mg-B interaction renders B a charge donor, resulting in Mg-B repulsion and Mg unit cell expansion. Mg-C peak shift to lower binding energies (C-1s XPS), decreases incubation time to ~ 2.25 h and enhances H-uptake kinetics. Various atomic interactions influence the reduction of incubation time in H-uptake and increase its kinetics in the order: (Mg → C; B → C)B/C≈0.09, B: donor > (Mg → C)B/C=0 > (ternary Mg → B → C)B/C>0.09, B: acceptor.

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Facile Synthesis of SnO2 Aerogel/Reduced Graphene Oxide Nanocomposites via in Situ Annealing for the Photocatalytic Degradation of Methyl Orange

Nanomaterials ◽

10.3390/nano9030358 ◽

2019 ◽

Vol 9 (3) ◽

pp. 358 ◽

Cited By ~ 17

Author(s):

Taehee Kim ◽

Vinayak Parale ◽

Hae-Noo-Ree Jung ◽

Younghun Kim ◽

Zied Driss ◽

...

Keyword(s):

Photocatalytic Activity ◽

Graphene Oxide ◽

Methyl Orange ◽

Reduced Graphene Oxide ◽

Chemical Interaction ◽

Sol Gel ◽

Precursor Solution ◽

Peak Shift ◽

Reduced Graphene

SnO2 aerogel/reduced graphene oxide (rGO) nanocomposites were synthesized using the sol–gel method. A homogeneous dispersion of graphene oxide (GO) flakes in a tin precursor solution was captured in a three-dimensional network SnO2 aerogel matrix and successively underwent supercritical alcohol drying followed by the in situ thermal reduction of GO, resulting in SnO2 aerogel/rGO nanocomposites. The chemical interaction between aerogel matrix and GO functional groups was confirmed by a peak shift in the Fourier transform infrared spectra and a change in the optical bandgap of the diffuse reflectance spectra. The role of rGO in 3D aerogel structure was studied in terms of photocatalytic activity with detailed mechanism of the enhancement such as electron transfer between the GO and SnO2. In addition, the photocatalytic activity of these nanocomposites in the methyl orange degradation varied depending on the amount of rGO loading in the SnO2 aerogel matrix; an appropriate amount of rGO was required for the highest enhancement in the photocatalytic activity of the SnO2 aerogel. The proposed nanocomposites could be a useful solution against water pollutants.

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Significant enhancement of the electrochemical hydrogen uptake of reduced graphene oxide via boron-doping and decoration with Pd nanoparticles

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2020.07.128 ◽

2020 ◽

Vol 45 (53) ◽

pp. 28951-28963

Author(s):

Emmanuel Boateng ◽

Jesse Smiles Dondapati ◽

Antony Raj Thiruppathi ◽

Aicheng Chen

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Boron Doping ◽

Pd Nanoparticles ◽

Hydrogen Uptake ◽

Significant Enhancement ◽

Reduced Graphene

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Reduced Graphene Oxide/Carbon Nanotube Composites for High Electrochemical Performance Supercapacitors

Materials Science Forum ◽

10.4028/www.scientific.net/msf.937.25 ◽

2018 ◽

Vol 937 ◽

pp. 25-29 ◽

Cited By ~ 1

Author(s):

Yan Zhen Huang ◽

Xiao Min Chen ◽

Dong Xu Li

Keyword(s):

Graphene Oxide ◽

Carbon Nanotube ◽

Electrochemical Performance ◽

Reduced Graphene Oxide ◽

Surface Area ◽

Weight Ratio ◽

Single Atom ◽

Homogeneous Distribution ◽

Thick Sheet ◽

Reduced Graphene

Graphene, whose structure is composed of a single-atom-thick sheet of sp2-hybridized carbon atom, provides large specific surface area, excellent mechanical and chemical properties. In this paper, reduced graphene oxide/carbon nanotube (rGO/CNT) composite, which had superior electrochemical performance, was synthesized via a facile, handy and cheap method. Electrochemical tests showed that rGO/CNT composite that the weight ratio of graphene oxide (GO) to CNTs is 7.5 to 1 exhibited the specific capacitance was 346.84 F/g at the current density of 2 A/g in 1 M H2SO4. The good performance of rGO/CNT composite was ascribed to huge surface area of rGO and homogeneous distribution of CNT, which prevented the aggregation of rGO sheets, increased the path of electron circulation and speeded up the electrolyte penetrating into the materials. Therefore, rGO/CNT composite had great potential on supercapacitors.

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Interactions of polymers with reduced graphene oxide: van der Waals binding energies of benzene on graphene with defects

Physical Chemistry Chemical Physics ◽

10.1039/c3cp53922a ◽

2014 ◽

Vol 16 (1) ◽

pp. 33-37 ◽

Cited By ~ 28

Author(s):

Mohamed Hassan ◽

Michael Walter ◽

Michael Moseler

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Van Der Waals ◽

Binding Energies ◽

Reduced Graphene

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Poly(3,4-ethylene dioxythiophene):Poly(styrene sulfonate)-Functionalized Reduced Graphene Oxide Electrode for Ionic Electroactive Polymer Actuators

Science of Advanced Materials ◽

10.1166/sam.2020.3642 ◽

2020 ◽

Vol 12 (3) ◽

pp. 313-318

Author(s):

Minjeong Park ◽

Sangwoo Kim ◽

Keun Yong Sohn ◽

Seonpil Kim ◽

Minhyon Jeon

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Weight Ratio ◽

Electroactive Polymer ◽

Water Evaporation ◽

Pressing Method ◽

Styrene Sulfonate ◽

Reduced Graphene ◽

Poly Styrene Sulfonate ◽

Composite Paper

Ionic electroactive polymer (IEAP) actuators, which offer advantages such as reduced device weight, flexibility, and large deformation under low voltages (1–5 V), have found utility in applications such as biomimetic robots, actuators, and sensors. In this context, in this study, we fabricate poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)-reduced graphene oxide (PEDOT:PSS-rGO) composite paper electrodes for actuator application. PEDOT:PSS-rGO paper electrodes are prepared by vacuum filtration of a PEDOT:PSS-rGO mixture that is subsequently subjected to heat treatment under an argon atmosphere via furnace annealing. We find that a 5:1 weight ratio of PEDOT:PSS-GO provides the lowest sheet resistance. We next fabricate a PEDOT:PSS-rGO actuator via filtration and the hot-pressing method with rGO paper electrodes, which have hydrophobic properties and low liquid permeability that effectively prevents water evaporation, and we examine its actuating performance. Our results indicate that after functionalization with PEDOT:PSS, the electrical properties and surface roughness of PEDOT:PSS-rGO composite paper electrode are improved. Further, the mechanical properties of the IEAP actuator based on the PEDOT:PSS-rGO paper electrodes exhibits enhanced performance by a factor of 4 relative to an actuator with conventional rGO electrodes.

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The Influence of Dispersion State of Graphene Sheets on the Microstructure and Thermal Conductivity of Free-Standing Reduced Graphene Oxide Films

NANO ◽

10.1142/s1793292019500383 ◽

2019 ◽

Vol 14 (03) ◽

pp. 1950038 ◽

Cited By ~ 2

Author(s):

Xiaorui Wang ◽

Shuangling Jin ◽

Rui Zhang ◽

Yan Liu ◽

Jiangcan Wang ◽

...

Keyword(s):

Thermal Conductivity ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Hydrothermal Process ◽

Weight Ratio ◽

Atomic Ratio ◽

Ammonia Solution ◽

Free Standing ◽

Reduced Graphene ◽

Dispersion State

Reduced graphene oxide (rGO) aqueous dispersions were synthesized from GO suspensions with hydrazine as reducing agent via a microwave-hydrothermal process in ammonia solution. The rGO films were fabricated by vacuum filtration of above dispersions. When the weight ratio of hydrazine to GO (R[Formula: see text]) increases from 0.125 to 9, the dispersion stability of rGO nanosheets in hydrazine/ammonia solution degrades gradually, the surfaces of resultant films become rough from smooth and large interspaces turn up in the transverse section. With the increasing of R[Formula: see text], the C/O atomic ratio and orientation degree of (002) plane of rGO films increase, and the in-plane thermal conductivity also increases, achieving a maximum value of 1056[Formula: see text]W/m K when R[Formula: see text] is 3.375, then decreases because large interspaces in the rGO film with higher reduction degree greatly limit the thermal transport due to the severe phonon scatterings at the sheets boundaries.

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Oxidation Prevention Properties of Reduced Graphene Oxide Mixed with 1-Octanethiol-Coated Copper Nanopowder Composites

Journal of Nanomaterials ◽

10.1155/2016/1050183 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8

Author(s):

Danee Cho ◽

Dahyun Choi ◽

Youngjun Pyo ◽

Rajendra C. Pawar ◽

Yongil Kim ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Weight Ratio ◽

Photoemission Spectroscopy ◽

Cu Nanoparticles ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Reduced Graphene ◽

Coating Layers

1-Octanethiol-coated Cu nanoparticles were mixed with reduced graphene oxide (rGO) to fabricate Cu nanoinks with enhanced oxidation prevention. Graphene oxide (GO) was synthesized using modified Hummer’s method and rGO was reduced from GO using hydrazine hydrate. Copper nanoinks were fabricated with varying concentrations of rGO (Cu : rGO ratios of 100 : 1, 500 : 1, and 1000 : 1 wt.%). The coating layers on the copper nanoparticles and rGO were observed using transmission electron microscopy and characterized by X-ray photoemission spectroscopy, X-ray diffraction, and Raman spectroscopy. It was observed that surface roughness increased as the concentration of rGO in Cu patterns increased, and an optimized Cu : rGO weight ratio of 1,000 : 1 was established. After sintering, the electrical properties and corrosion resistance of copper patterns both with and without rGO were measured and monitored for 200 days. The copper pattern with rGO (Cu : rGO = 1,000 : 1) was found to maintain its initial resistivity (1.63 × 10−7 Ω·m) for 150 days. Corrosion tests were conducted to confirm the oxidation prohibition of rGO. The resistance polarization(Rp)of the copper pattern was measured to be 1.5 times higher than that of the copper pattern without rGO. Thus, rGO was shown to prevent oxidation and improve the conductivity of copper patterns.

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Preparation and properties of reduced graphene oxide-carbon nanotubes aerogel/cotton flexible composite fabric with electromagnetic shielding function

Journal of Industrial Textiles ◽

10.1177/15280837211060879 ◽

2021 ◽

pp. 152808372110608

Author(s):

Peng Wang ◽

Shuqiang Liu ◽

Man Zhang ◽

Zheng-Ze Pan ◽

Gaihong Wu ◽

...

Keyword(s):

Carbon Nanotubes ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Electromagnetic Interference ◽

Rapid Development ◽

Weight Ratio ◽

Waterborne Polyurethane ◽

Shielding Effectiveness ◽

Graphene Aerogel ◽

Reduced Graphene

The electromagnetic pollution has become a serious problem with the rapid development of electromagnetic industry. The present work prepared an electromagnetic interference (EMI) functional composite fabric. Reduced graphene oxide (rGO)-carbon nanotubes (CNTs) aerogel with three-dimensional (3-D) architecture were coated to the cotton fabric with the assistance of waterborne polyurethane (WPU). The structure of graphene aerogel was affected by the amount of CNTs. Small amount of CNTs is helpful to minish the pore size of aerogel and thus improve the EMI value. However, it has been shown that excess CNTs will destroy the 3-D architecture of graphene aerogel. Result shows that the EMI shielding effectiveness exceeded 35 dB when the weight ratio of rGO and CNTs was 7:3, and EMI value of the corresponding composite fabric samples reached 34 dB. Consequently, excellent EMI results were obtained by the unique 3-D rGO-CNTs aerogel in the case of a small nano-carbon material amount. The present work will be expected to make contributions to the practical application of rGO-CNTs aerogel.

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