scholarly journals Analysis of Reduced Graphene Oxides by X-ray Photoelectron Spectroscopy and Electrochemical Capacitance

2013 ◽  
Vol 42 (8) ◽  
pp. 924-926 ◽  
Author(s):  
Michio Koinuma ◽  
Hikaru Tateishi ◽  
Kazuto Hatakeyama ◽  
Shinsuke Miyamoto ◽  
Chikako Ogata ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Graphene Oxides ◽  
Electrochemical Capacitance ◽  
X Ray ◽  
Reduced Graphene ◽  
Reduced Graphene Oxides

scholarly journals Characterization of Graphite Oxide and Reduced Graphene Oxide Obtained from Different Graphite Precursors and Oxidized by Different Methods Using Raman Spectroscopy Statistical Analysis

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 769
Author(s):  
Roksana Muzyka ◽  
Sabina Drewniak ◽  
Tadeusz Pustelny ◽  
Marcin Sajdak ◽  
Łukasz Drewniak
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Statistical Analysis ◽  
Reduced Graphene Oxide ◽  
Graphite Oxide ◽  
Photoelectron Spectroscopy ◽  
Graphene Oxides ◽  
Preparation Methods ◽  
X Ray ◽  
Reduced Graphene

In this paper, various graphite oxide (GO) and reduced graphene oxide (rGO) preparation methods are analyzed. The obtained materials differed in their properties, including (among others) their oxygen contents. The chemical and structural properties of graphite, graphite oxides, and reduced graphene oxides were previously investigated using Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). In this paper, hierarchical clustering analysis (HCA) and analysis of variance (ANOVA) were used to trace the directions of changes of the selected parameters relative to a preparation method of such oxides. We showed that the oxidation methods affected the physicochemical properties of the final products. The aim of the research was the statistical analysis of the selected properties in order to use this information to design graphene oxide materials with properties relevant for specific applications (i.e., in gas sensors).

Enhanced 1T phase promotes sodium storage performances of MoS2 flower-like spheres with embedded reduced graphene oxides

2021 ◽  
Vol 297 ◽  
pp. 122027
Author(s):  
Xianglin Yu ◽  
Ruixue Li ◽  
Xinyu Hu ◽  
Ren He ◽  
Kehui Xue ◽  
...  
Keyword(s):  
Graphene Oxides ◽  
Reduced Graphene ◽  
Reduced Graphene Oxides ◽  
Sodium Storage

X-Ray Photoelectron Spectroscopy Study on Reduction of Graphene Oxide with Hydrazine Hydrate

2011 ◽  
Vol 287-290 ◽  
pp. 539-543 ◽  
Author(s):  
Wen Shi Ma ◽  
Jun Wen Zhou ◽  
Xiao Dan Lin
Keyword(s):  
Graphene Oxide ◽  
Hydrazine Hydrate ◽  
Photoelectron Spectroscopy ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
Chemical Compositions ◽  
Total Oxygen ◽  
Graphene Oxides ◽  
X Ray ◽  
Oxygen Groups

Graphene oxide was prepared through Hummers' method，then different reduced graphenes were prepared via reduction of graphene oxide with hydrazine hydrate for 1h、12h and 24h. X-ray photoelectron spectroscopy (XPS) was used for the characterization of graphene oxide and the reduced graphenes. The variation of the contents of carbon in carbon and oxygen functional groups and chemical compositions of graphene oxides were investigated through analysis the content of different carbon atoms in different reduced graphenes. The results showed that the reduction reaction was very fast in the first 1 h, the content of total oxygen bonded carbon atoms decreased from 83.6% to 22.1%, and then after the reduction rate became very slow. After 12h, the content of total oxygen bonded carbon atom is 19.56%, only 2.54% lower than that of 1h’s. At the same time, C-N was introduced in the graphene oxides; this increased the stereo-hindrance for hydrazine hydrate attacking the C-Oxygen groups, thus reduced the reduction rate. After reduction for 24h, there still exists 16.4% oxygen bonded carbon atoms and the total conversion ratio of graphene approaches 70%.

FeYO3@rGO nanocomposites: Synthesis, characterization and application in photooxidative degradation of atrazine under visible light

2021 ◽  
Vol 11 (5) ◽  
pp. 706-716
Author(s):  
Nada D. Al-Khthami ◽  
Tariq Altalhi ◽  
Mohammed Alsawat ◽  
Mohamed S. Amin ◽  
Yousef G. Alghamdi ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Structural Surface ◽  
Adsorption Desorption

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.

Effect of thermally reduced graphene oxides obtained at different temperatures on the barrier and mechanical properties of polypropylene/TRGO and polyamide‐6/TRGO nanocomposites

2018 ◽  
Vol 40 (S2) ◽  
pp. E1746-E1756 ◽  
Author(s):  
Moisés Gómez ◽  
Alexis Díaz ◽  
Paula Reyes ◽  
Mehrdad Yazdani‐Pedram ◽  
Sônia Marlí Bohrz Nachtigall ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyamide 6 ◽  
Graphene Oxides ◽  
Reduced Graphene ◽  
Different Temperatures ◽  
Reduced Graphene Oxides

Hydrophobic ligand-mediated hierarchical Cu nanoparticles on reduced graphene oxides for SERS platform

CrystEngComm ◽  
2016 ◽  
Vol 18 (40) ◽  
pp. 7764-7771 ◽  
Author(s):  
LiLi He ◽  
Changqing Liu ◽  
Jiugang Hu ◽  
Wanmiao Gu ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Cu Nanoparticles ◽  
Graphene Oxides ◽  
Reduced Graphene ◽  
Reduced Graphene Oxides ◽  
Hydrophobic Ligand

scholarly journals Reduced graphene oxides with engineered defects enable efficient electrochemical reduction of dinitrogen to ammonia in wide pH range

Nano Energy ◽  
2020 ◽  
Vol 68 ◽  
pp. 104323 ◽  
Author(s):  
Mingli Zhang ◽  
Changhyeok Choi ◽  
Rupeng Huo ◽  
Geun Ho Gu ◽  
Song Hong ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Graphene Oxides ◽  
Reduced Graphene ◽  
Wide Ph Range ◽  
Reduced Graphene Oxides ◽  
Ph Range

scholarly journals Microwave-assisted fast fabrication of a nanosized Pt3Co alloy on reduced graphene oxides

2014 ◽  
Vol 35 (12) ◽  
pp. 2029-2037 ◽  
Author(s):  
Juanjuan Shi ◽  
Renfeng Nie ◽  
Mengyuan Zhang ◽  
Mengsi Zhao ◽  
Zhaoyin Hou
Keyword(s):  
Graphene Oxides ◽  
Microwave Assisted ◽  
Reduced Graphene ◽  
Reduced Graphene Oxides

scholarly journals Mechanisms of Two-Electron and Four-Electron Electrochemical Oxygen Reduction Reactions at Nitrogen-Doped Reduced Graphene Oxide

2019 ◽  
Author(s):  
Hyo Won Kim ◽  
Vanessa Jane Bukas ◽  
Hun Park ◽  
Sojung Park ◽  
Kyle M. Diederichsen ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Isotope Effects ◽  
Underlying Mechanism ◽  
Reduction Reaction ◽  
Graphene Oxides ◽  
Nitrogen Doped ◽  
General Chemical ◽  
Reduced Graphene

Doped carbon-based systems have been extensively studied over the past decade as active electrocatalysts for both the two-electron (2e-) and four-electron (4e-) oxygen reduction reaction (ORR). However, the mechanisms for ORR are generally poorly understood. Here we report an extensive experimental and first-principles theoretical study of the ORR at nitrogen-doped reduced graphene oxides (NrGO). We synthesize three distinct NrGO catalysts and investigate their chemical and structural properties in detail via X-ray photoelectron spectroscopy, infrared and Raman spectroscopy, high-resolution transmission electron microscopy and thin-film electrical conductivity. ORR experiments include the pH dependences of 2e- versus 4e- ORR selectivity, ORR onset potentials, Tafel slopes and H/D kinetic isotope effects. These experiments show very different ORR behavior for the three catalysts, both in terms of selectivity and the underlying mechanism which proceeds either via coupled proton-electron transfers (CPETs) or non-CPETs. Reasonable structural models developed from DFT rationalize this behavior. The key determinant between CPET vs. non-CPET mechanisms is the electron density at the Fermi level under operating ORR conditions. Regardless of the reaction mechanism or electrolyte pH, however, we identify the ORR active sites as sp2 carbons that are located next to oxide regions. This assignment highlights the importance of oxygen functional groups, while details of (modest) N-doping may still affect the overall catalytic activity, and likely also the selectivity, by modifying the general chemical environment around the active site.

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