scholarly journals Synthesis and Electrochemical Study of Three-Dimensional Graphene-Based Nanomaterials for Energy Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1295
Author(s):  
Antony R. Thiruppathi ◽  
Boopathi Sidhureddy ◽  
Emmanuel Boateng ◽  
Dmitriy V. Soldatov ◽  
Aicheng Chen
Keyword(s):  
Energy Storage ◽  
Energy Conversion ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
High Surface ◽  
Three Dimensional ◽  
Reduction Reaction ◽  
Chemical Compositions ◽  
Supercapacitor Electrode ◽  
X Ray

Graphene is an attractive soft material for various applications due to its unique and exclusive properties. The processing and preservation of 2D graphene at large scales is challenging due to its inherent propensity for layer restacking. Three-dimensional graphene-based nanomaterials (3D-GNMs) preserve their structures while improving processability along with providing enhanced characteristics, which exhibit some notable advantages over 2D graphene. This feature article presents recent trends in the fabrication and characterization of 3D-GNMs toward the study of their morphologies, structures, functional groups, and chemical compositions using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Owing to the attractive properties of 3D-GNMs, which include high surface areas, porous structures, improved electrical conductivity, high mechanical strength, and robust structures, they have generated tremendous interest for various applications such as energy storage, sensors, and energy conversion. This article summarizes the most recent advances in electrochemical applications of 3D-GNMs, pertaining to energy storage, where they can serve as supercapacitor electrode materials and energy conversion as oxygen reduction reaction catalysts, along with an outlook.

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%.

scholarly journals Modified Activation Process for Supercapacitor Electrode Materials from African Maize Cob

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5412
Author(s):  
Moses Kigozi ◽  
Ravi Kali ◽  
Abdulhakeem Bello ◽  
Balaji Padya ◽  
Godwin Mong Kalu-Uka ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
Chemical Activation ◽  
Mesoporous Structure ◽  
Activation Process ◽  
Energy Storage Devices ◽  
Supercapacitor Electrode ◽  
X Ray ◽  
Bet Analysis

In this work, African maize cobs (AMC) were used as a rich biomass precursor to synthesize carbon material through a chemical activation process for application in electrochemical energy storage devices. The carbonization and activation were carried out with concentrated Sulphuric acid at three different temperatures of 600, 700 and 800 °C, respectively. The activated carbon exhibited excellent microporous and mesoporous structure with a specific surface area that ranges between 30 and 254 m2·g−1 as measured by BET analysis. The morphology and structure of the produced materials are analyzed through Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Boehm titration, X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy. X-ray photoelectron spectroscopy indicates that a considerable amount of oxygen is present in the materials. The functional groups in the activated carbon enhanced the electrochemical performance and improved the material’s double-layer capacitance. The carbonized composite activated at 700 °C exhibited excellent capacitance of 456 F g−1 at a specific current of 0.25 A g−1 in 6 M KOH electrolyte and showed excellent stability after 10,000 cycles. Besides being a low cost, the produced materials offer good stability and electrochemical properties, making them suitable for supercapacitor applications.

scholarly journals Non-Thermal Plasma-Modified Ru-Sn-Ti Catalyst for Chlorinated Volatile Organic Compound Degradation

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1456
Author(s):  
Yujie Fu ◽  
You Zhang ◽  
Qi Xin ◽  
Zhong Zheng ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Surface Oxidation ◽  
Treatment Method ◽  
X Ray ◽  
Chlorinated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Doped Titania

Chlorinated volatile organic compounds (CVOCs) are vital environmental concerns due to their low biodegradability and long-term persistence. Catalytic combustion technology is one of the more commonly used technologies for the treatment of CVOCs. Catalysts with high low-temperature activity, superior selectivity of non-toxic products, and resistance to chlorine poisoning are desirable. Here we adopted a plasma treatment method to synthesize a tin-doped titania loaded with ruthenium dioxide (RuO2) catalyst, possessing enhanced activity (T90%, the temperature at which 90% of dichloromethane (DCM) is decomposed, is 262 °C) compared to the catalyst prepared by the conventional calcination method. As revealed by transmission electron microscopy, X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction, the high surface area of the tin-doped titania catalyst and the enhanced dispersion and surface oxidation of RuO2 induced by plasma treatment were found to be the main factors determining excellent catalytic activities.

Interpenetrating Gels as Conducting/Adhering Matrices Enabling High-Performance Silicon Anodes

2021 ◽  
Author(s):  
Tingting Xia ◽  
Chengfei Xu ◽  
Pengfei Dai ◽  
Xiaoyun Li ◽  
Riming Lin ◽  
...  
Keyword(s):  
Energy Storage ◽  
High Performance ◽  
Electrode Materials ◽  
Three Dimensional ◽  
Electrochemical Energy Storage ◽  
Active Materials ◽  
Silicon Anodes ◽  
Weak Binding ◽  
Binding Forces

Three-dimensional (3D) conductive polymers are promising conductive matrices for electrode materials toward electrochemical energy storage. However, their fragile nature and weak binding forces with active materials could not guarantee long-term...

scholarly journals Pore Modification and Phosphorus Doping Effect on Phosphoric Acid-Activated Fe-N-C for Alkaline Oxygen Reduction Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1519
Author(s):  
Jong Gyeong Kim ◽  
Sunghoon Han ◽  
Chanho Pak
Keyword(s):  
Phosphoric Acid ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Electronic States ◽  
Nitrogen Adsorption ◽  
Reduction Reaction ◽  
Phosphorus Doping ◽  
X Ray ◽  
Precious Metal Catalysts ◽  
Adsorption Desorption

The price and scarcity of platinum has driven up the demand for non-precious metal catalysts such as Fe-N-C. In this study, the effects of phosphoric acid (PA) activation and phosphorus doping were investigated using Fe-N-C catalysts prepared using SBA-15 as a sacrificial template. The physical and structural changes caused by the addition of PA were analyzed by nitrogen adsorption/desorption and X-ray diffraction. Analysis of the electronic states of Fe, N, and P were conducted by X-ray photoelectron spectroscopy. The amount and size of micropores varied depending on the PA content, with changes in pore structure observed using 0.066 g of PA. The electronic states of Fe and N did not change significantly after treatment with PA, and P was mainly found in states bonded to oxygen or carbon. When 0.135 g of PA was introduced per 1 g of silica, a catalytic activity which was increased slightly by 10 mV at −3 mA/cm2 was observed. A change in Fe-N-C stability was also observed through the introduction of PA.

scholarly journals Structure and Characterization of TiC/GLC Multilayered Films with Various Bilayers Periods

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 787
Author(s):  
Weiqi Wang ◽  
Xiaoming Ling ◽  
Rui Wang ◽  
Wenhao Nie ◽  
Li Ji ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Chemical Compositions ◽  
Closed Field ◽  
Multilayered Structures ◽  
Multilayered Films ◽  
Sputtering Deposition ◽  
X Ray ◽  
Mechanical And Tribological Properties ◽  
Self Organizing

The spontaneously self-organizing multilayered graphite-like carbon (denoted as GLC) /TiC films with various bilayer periods in the range of 13.3–17.5 nm were deposited on silicon and 1Cr18Mn8Ni5N stainless steel substrates using closed field magnetron sputtering deposition facility. The microstructures and chemical compositions of the prepared multilayered films were characterized by scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy respectively. The self-organizing multilayered structures in all of the films consisted of titanium carbide layers and sp2-rich carbon layers periodically alternate arrangement. The TiC contents and bilayer periods of the multilayered films can be controlled by means of adjusting of sputtering current of graphite target. Furthermore, the mechanical and tribological performances of the prepared films were appraised by nano-indentor, scratch measures, and ball-on-plate tribometer respectively. The results indicated that multilayer structure endowed the as-deposited TiC/GLC films outstanding mechanical and tribological properties, especially the multilayer film with 15.9 nm bilayer period deposited at 10 A sputtering current showed the excellent adhesion strength and hardness; Simultaneously it also exhibited the lowest average friction coefficient in the humid environment owing to its high content of sp2 hybrid carbon.

scholarly journals Synthesis of Three-Dimensional Fe3O4/Graphene Aerogels for the Removal of Arsenic Ions from Water

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yan Ye ◽  
Da Yin ◽  
Bin Wang ◽  
Qingwen Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
3D Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Aerogels ◽  
Transmission Electron ◽  
Potential Applications ◽  
Removal Of Arsenic

We report the synthesis of three-dimensional Fe3O4/graphene aerogels (GAs) and their application for the removal of arsenic (As) ions from water. The morphology and properties of Fe3O4/GAs have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum inference device. The 3D nanostructure shows that iron oxide nanoparticles are decorated on graphene with an interconnected network structure. It is found that Fe3O4/GAs own a capacity of As(V) ions adsorption up to 40.048 mg/g due to their remarkable 3D structure and existence of magnetic Fe3O4nanoparticles for separation. The adsorption isotherm matches well with the Langmuir model and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. In addition to the excellent adsorption capability, Fe3O4/GAs can be easily and effectively separated from water, indicating potential applications in water treatment.

scholarly journals Microwave synthesis of high-quality and uniform 4 nm ZnFe2O4 nanocrystals for application in energy storage and nanomagnetics

2016 ◽  
Vol 7 ◽  
pp. 1350-1360 ◽  
Author(s):  
Christian Suchomski ◽  
Ben Breitung ◽  
Ralf Witte ◽  
Michael Knapp ◽  
Sondes Bauer ◽  
...  
Keyword(s):  
Energy Storage ◽  
Photoelectron Spectroscopy ◽  
Zinc Ferrite ◽  
Sol Gel ◽  
High Capacity ◽  
Spherical Shape ◽  
Freezing Temperature ◽  
Ex Situ ◽  
Edge Structure ◽  
X Ray

Magnetic nanocrystals with a narrow size distribution hold promise for many applications in different areas ranging from biomedicine to electronics and energy storage. Herein, the microwave-assisted sol–gel synthesis and thorough characterization of size-monodisperse zinc ferrite nanoparticles of spherical shape is reported. X-ray diffraction, 57Fe Mössbauer spectroscopy and X-ray photoelectron spectroscopy all show that the material is both chemically and phase-pure and adopts a partially inverted spinel structure with Fe3+ ions residing on tetrahedral and octahedral sites according to (Zn0.32Fe0.68)tet[Zn0.68Fe1.32]octO4±δ. Electron microscopy and direct-current magnetometry confirm the size uniformity of the nanocrystals, while frequency-dependent alternating-current magnetic susceptibility measurements indicate the presence of a superspin glass state with a freezing temperature of about 22 K. Furthermore, as demonstrated by galvanostatic charge–discharge tests and ex situ X-ray absorption near edge structure spectroscopy, the as-prepared zinc ferrite nanocrystals can be used as a high-capacity anode material for Li-ion batteries, showing little capacity fade – after activation – over hundreds of cycles. Overall, in addition to the good material characteristics, it is remarkable that the microwave-based synthetic route is simple, easily reproducible and scalable.

scholarly journals Graphitic Nitrogen in Carbon Catalysts Important for the Reduction of Nitrite Revealed by 15N NMR Spectroscopy at Natural Abundance

2020 ◽  
Author(s):  
Zheng Chen ◽  
Aleksander Jaworski ◽  
Jianhong Chen ◽  
Tetyana Budnyak ◽  
Ireneusz Szewczyk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Reduction Reaction ◽  
Nitrite Reduction ◽  
15N Nmr ◽  
Carbon Catalyst ◽  
X Ray ◽  
Wide Range ◽  
Alkaline Conditions

Metal-free nitrogen-doped carbon is considered as a green functional material, but the structural determination of the atomic positions of nitrogen remains challenging. We recently demonstrated that directly-excited solid state <sup>15</sup>N NMR (ssNMR) spectroscopy is a powerful tool for the determination of such positions in an N-doped carbon at natural <sup>15</sup>N isotope abundance. Here we present a green chemistry approach to the synthesis of N-doped carbon using cellulose as precursor, and a study of the catalytic properties and atomic structures of the related catalyst. The N-doped carbon (NH<sub>3</sub>) was obtained by oxidation of cellulose with HNO<sub>3</sub> followed by ammonolysis at 800°C. It had a N content of 6.5 wt.% and a surface area of 557 m<sup>2 </sup>g<sup>–1</sup>, and <sup>15</sup>N ssNMR spectroscopy provided evidence for graphitic nitrogen besides of regular pyrrolic and pyridinic nitrogen. This structure determination enabled probing the role of graphitic nitrogen for electrocatalytic reactions, such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and nitrite reduction reaction. The N-doped carbon catalyst (NH<sub>3</sub>) had higher electrocatalytic activities in OER and HER under alkaline conditions and a higher activity for nitrite reduction, as compared with a catalyst prepared by carbonization of the HNO<sub>3</sub>-treated cellulose in N<sub>2</sub>. The electrocatalytic selectivity for nitrite reduction of the N-doped carbon catalyst (NH<sub>3</sub>) was directly related to the graphitic nitrogen functions. Complementary structural analysis by means of <sup>13</sup>C and <sup>1</sup>H ssNMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and low-temperature N<sub>2 </sub>adsorption were preformed and provided support to the findings. The results show that directly-excited <sup>15</sup>N ssNMR at natural <sup>15</sup>N abundance is generally capable to provide information on N-doped carbon materials, and it is expected that the approach can be applied to a wide range of solids with an intermediate amount of N atoms.

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