Rh/Ni wet-impregnated Ia3d mesostructured aluminosilicate and r-GO catalysts for hydrodeoxygenation of phenoxybenzene

2017 ◽  
Vol 41 (16) ◽  
pp. 7893-7907 ◽  
Author(s):  
Sudhakar Pichaikaran ◽  
Arumugam Pandurangan
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Structural Properties ◽  
Bet Surface Area ◽  
Xps Analysis ◽  
Icp Oes ◽  
Reduced Graphene ◽  
Ft Ir

Rh/Ni bimetallic supported bifunctional 3D porous aluminosilicate and Rh/Ni supported reduced graphene oxide (r-GO) catalysts were synthesised and their structural properties evaluated by XRD, BET-surface area, FT-IR, NH3-TPD, H2-TPR, ICP-OES, HRTEM-EDAX and XPS analysis.

scholarly journals Activated graphene as a material for supercapacitor electrodes: effects of surface area, pore size distribution and hydrophilicity

2019 ◽  
Vol 21 (32) ◽  
pp. 17901-17912 ◽  
Author(s):  
Artem Iakunkov ◽  
Vasyl Skrypnychuk ◽  
Andreas Nordenström ◽  
Elizaveta A. Shilayeva ◽  
Mikhail Korobov ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Pore Volume ◽  
Bet Surface Area ◽  
Oxide Materials ◽  
Reduced Graphene

Activated reduced graphene oxide materials (a-rGO) with variation of N2 BET surface area 1000–3000 m2 g−1 were tested in supercapacitors. Correlations between electrode performance and pore size, pore volume, N2 and H2O BET surface area were evaluated.

scholarly journals Reduced Graphene Oxide-Supported Pt-Based Catalysts for PEM Fuel Cells with Enhanced Activity and Stability

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 256
Author(s):  
Irina V. Pushkareva ◽  
Artem S. Pushkarev ◽  
Valery N. Kalinichenko ◽  
Ratibor G. Chumakov ◽  
Maksim A. Soloviev ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Pem Fuel Cells ◽  
Polyol Process ◽  
Proton Exchange ◽  
Active Surface Area ◽  
Electrochemical Performances ◽  
Simultaneous Reduction ◽  
Reduced Graphene

Platinum (Pt)-based electrocatalysts supported by reduced graphene oxide (RGO) were synthesized using two different methods, namely: (i) a conventional two-step polyol process using RGO as the substrate, and (ii) a modified polyol process implicating the simultaneous reduction of a Pt nanoparticle precursor and graphene oxide (GO). The structure, morphology, and electrochemical performances of the obtained Pt/RGO catalysts were studied and compared with a reference Pt/carbon black Vulcan XC-72 (C) sample. It was shown that the Pt/RGO obtained by the optimized simultaneous reduction process had higher Pt utilization and electrochemically active surface area (EASA) values, and a better performance stability. The use of this catalyst at the cathode of a proton exchange membrane fuel cell (PEMFC) led to an increase in its maximum power density of up to 17%, and significantly enhanced its performance especially at high current densities. It is possible to conclude that the optimized synthesis procedure allows for a more uniform distribution of the Pt nanoparticles and ensures better binding of the particles to the surface of the support. The advantages of Pt/RGO synthesized in this way over conventional Pt/C are the high electrical conductivity and specific surface area provided by RGO, as well as a reduction in the percolation limit of the components of the electrocatalytic layer due to the high aspect ratio of RGO.

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

Synthesis of reduced graphene oxide/aluminum nanocomposites via chemical-mechanical processes

2018 ◽  
Vol 52 (22) ◽  
pp. 3015-3025 ◽  
Author(s):  
Daeyoung Kim ◽  
Heon Kang ◽  
Donghyun Bae ◽  
Seungjin Nam ◽  
Manuel Quevedo-Lopez ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Specific Surface ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Aluminum Powder ◽  
Mechanical Milling ◽  
Uniform Dispersion ◽  
Reduced Graphene

The present study employed a combination of solution-based synthesis and mechanical milling to develop reduced graphene oxide/aluminum composites, in order to achieve uniform dispersion of reduced graphene oxide and strong interfaces between reduced graphene oxide and aluminum. First, spherical aluminum powder was flattened via mechanical milling to afford a large specific surface area and many reaction sites for the graphene oxide. A hydrophilic surface was then created by coating the aluminum powder with polyvinyl alcohol. The polyvinyl alcohol-coated aluminum slurry was mixed with a graphene oxide suspension, thereby inducing a reaction between graphene oxide and polyvinyl alcohol via hydrogen bonding. After thermal reduction, the composite powder was further ball milled and hot-pressed at 500℃ to produce a reduced graphene oxide/aluminum composite. The dispersion of reduced graphene oxide in the composite, as well as the mechanical and thermal behaviors of the composite, improved with increased flattening and specific surface area of the starting aluminum powder.

scholarly journals Novel Activated Carbon Nanofibers Composited with Cost-Effective Graphene-Based Materials for Enhanced Adsorption Performance toward Methane

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2064
Author(s):  
Faten Ermala Che Othman ◽  
Norhaniza Yusof ◽  
Noorfidza Yub Harun ◽  
Muhammad Roil Bilad ◽  
Juhana Jaafar ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Activated Carbon ◽  
Specific Surface ◽  
Pore Size ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Carbon Nanofibers ◽  
Specific Surface Area ◽  
Activated Carbon Nanofibers ◽  
Reduced Graphene

Various types of activated carbon nanofibers’ (ACNFs) composites have been extensively studied and reported recently due to their extraordinary properties and applications. This study reports the fabrication and assessments of ACNFs incorporated with graphene-based materials, known as gACNFs, via simple electrospinning and subsequent physical activation process. TGA analysis proved graphene-derived rice husk ashes (GRHA)/ACNFs possess twice the carbon yield and thermally stable properties compared to other samples. Raman spectra, XRD, and FTIR analyses explained the chemical structures in all resultant gACNFs samples. The SEM and EDX results revealed the average fiber diameters of the gACNFs, ranging from 250 to 400 nm, and the successful incorporation of both GRHA and reduced graphene oxide (rGO) into the ACNFs’ structures. The results revealed that ACNFs incorporated with GRHA possesses the highest specific surface area (SSA), of 384 m2/g, with high micropore volume, of 0.1580 cm3/g, which is up to 88% of the total pore volume. The GRHA/ACNF was found to be a better adsorbent for CH4 compared to pristine ACNFs and reduced graphene oxide (rGO/ACNF) as it showed sorption up to 66.40 mmol/g at 25 °C and 12 bar. The sorption capacity of the GRHA/ACNF was impressively higher than earlier reported studies on ACNFs and ACNF composites. Interestingly, the CH4 adsorption of all ACNF samples obeyed the pseudo-second-order kinetic model at low pressure (4 bar), indicating the chemisorption behaviors. However, it obeyed the pseudo-first order at higher pressures (8 and 12 bar), indicating the physisorption behaviors. These results correspond to the textural properties that describe that the high adsorption capacity of CH4 at high pressure is mainly dependent upon the specific surface area (SSA), pore size distribution, and the suitable range of pore size.

scholarly journals Effect of Doping Temperatures and Nitrogen Precursors on the Physicochemical, Optical, and Electrical Conductivity Properties of Nitrogen-Doped Reduced Graphene Oxide

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3376 ◽  
Author(s):  
Nonjabulo P. D. Ngidi ◽  
Moses A. Ollengo ◽  
Vincent O. Nyamori
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Nitrogen Doped ◽  
Substitutional Doping ◽  
Reduced Graphene ◽  
Effect Of Doping

The greatest challenge in graphene-based material synthesis is achieving large surface area of high conductivity. Thus, tuning physico-electrochemical properties of these materials is of paramount importance. An even greater problem is to obtain a desired dopant configuration which allows control over device sensitivity and enhanced reproducibility. In this work, substitutional doping of graphene oxide (GO) with nitrogen atoms to induce lattice–structural modification of GO resulted in nitrogen-doped reduced graphene oxide (N-rGO). The effect of doping temperatures and various nitrogen precursors on the physicochemical, optical, and conductivity properties of N-rGO is hereby reported. This was achieved by thermal treating GO with different nitrogen precursors at various doping temperatures. The lowest doping temperature (600 °C) resulted in less thermally stable N-rGO, yet with higher porosity, while the highest doping temperature (800 °C) produced the opposite results. The choice of nitrogen precursors had a significant impact on the atomic percentage of nitrogen in N-rGO. Nitrogen-rich precursor, 4-nitro-ο-phenylenediamine, provided N-rGO with favorable physicochemical properties (larger surface area of 154.02 m2 g−1) with an enhanced electrical conductivity (0.133 S cm−1) property, making it more useful in energy storage devices. Thus, by adjusting the doping temperatures and nitrogen precursors, one can tailor various properties of N-rGO.

A process to enhance the specific surface area and capacitance of hydrothermally reduced graphene oxide

Nanoscale ◽  
2016 ◽  
Vol 8 (41) ◽  
pp. 17782-17787 ◽  
Author(s):  
Amira Alazmi ◽  
Omar El Tall ◽  
Shahid Rasul ◽  
Mohamed N. Hedhili ◽  
Shashikant P. Patole ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Specific Surface ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Reduced Graphene

A highly photoactive, visible-light-driven graphene/2D mesoporous TiO2 photocatalyst

2015 ◽  
Vol 17 (7) ◽  
pp. 3972-3978 ◽  
Author(s):  
Kyeong Min Cho ◽  
Kyoung Hwan Kim ◽  
Hyung Ouk Choi ◽  
Hee-Tae Jung
Keyword(s):  
Graphene Oxide ◽  
Visible Light ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Charge Separation ◽  
Mesoporous Tio2 ◽  
Tio2 Photocatalyst ◽  
Enhanced Absorption ◽  
Reduced Graphene ◽  
Visible Light Driven

In this paper, we have reported a new, visible-light-driven photocatalyst composed of 2D mesoporous TiO2 on reduced graphene oxide, which enables enhanced absorption of visible light, showing outstanding charge separation ability, and a large surface area.

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