INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2017
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IF 3.582
Bingying Gao,Mulenga Kalulu,Olayinka Oderinde,Jing Mei,Lili Ren
Polyvinylpyrrolidone (PVP) modified reduced graphene aerogel (PVP-GA) was prepared through hydrothermal reduction and chemical reduction of graphene oxide (GO) in the presence of PVP. The structure of PVP-GA was characterized using XRD , FTIR , SEM, TEM and BET specific surface area. The results showed that GO was reduced effectively in the presence of PVP and the PVP molecules were absorbed onto the basal plane of reduced graphene oxide (rGO) through non-covalent interactions. The preparation process was carried out in aqueous media at 120 °C for 10 h without using any toxic reducing agent, thereby making it a facile, environmental-friendly and economical approach for the synthesis of a three-dimensional (3D) interconnected graphene macrostructure. The as-prepared monolithic 3D graphene exhibits a loose and high porous structure , which may find potential applications for adsorbent, shock absorber , catalyst carrier and hydrogen storage materials. In addition, it confirmed that simultaneous hydrothermal reduction and chemical reduction routes would be of value for preparing 3D nonporous graphene-based materials via the use of cheap and environmentally-friendly PVP as a reducing agent.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
PHYSICA SCRIPTA
·
2024
·Vol. 99
·期 3
·035924
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IF 2.6
Ke Zhao,Jianzhao Cao,Ying Qi,Peng Wei,Jian Cheng,Yahong Xie
In our study, we selected three prevalent coal types from Xinjiang: Dahuangshan coal (referred to as Y-coal), Black Mountain coal (B-coal), and Kuche coal (K-coal). Initially, we assessed their morphological differences using electron microscopy. Subsequently, we evaluated the superiority of Y-coal through Thermogravimetric Analysis (TGA). Furthermore, we compared their performances using various electrochemical tests, including the J-V curve, dark current curve, open-circuit voltage curve, and Electrochemical Impedance Spectroscopy (EIS) curve. Ultimately, we investigated the potential of synthesizing graphene from Y-coal and its derivatives. The first step was the preparation of multilayer graphene (MG) by treating Y-coal with acid to obtain demineralized coal, followed by treatment in a tube furnace to obtain ultrafine powdered MG. The second step was then followed by successive oxidation and ultrasonication of the already obtained MG to obtain graphene oxide (GO). Finally, ascorbic acid (VC) was selected to treat GO to prepare an aqueous suspension of reduced graphene oxide (rGO). MG (2θ = 26.2°), GO (2θ = 12.4°) and rGO (2θ = 25.5°) were obtained by XRD analysis. C 1s and O 1S were analyzed by XPS spectra. The functional groups −OH, C=O, and −C=C–, which are unique to graphene and its derivatives, were comparatively analyzed using infrared spectroscopy. The change of π→π* was analyzed by the UV–vis method. The absorbance was further found in combination with PL spectra. Immediately after, the morphology of graphite and its derivatives was analyzed by SEM, HRTEM, the physical properties by contact angle and BET, and finally the content of elements C and O by EDS. The successful demonstration of the superiority of the synthesized MG and its derivatives was achieved.
研究领域:
材料科学
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能源科学
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DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
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2015
·Vol. 119
·期 4
·1483-1490
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IF 1.704
Wang Xiaoxia,Yu Jianhua,Dong Hongzhou,Yu Mingxun,Zhang Baoqin,Wang Wen,Dong Lifeng
In this work, metal oxide (MnO 2 , SnO 2 and Co 3 O 4 )–graphene composite materials were successfully prepared via different synthesis methods. Uniform metal oxide nanoparticles were well dispersed on graphene sheets, and transmission electron microscopy characterizations showed that the average sizes of MnO 2 , SnO 2 , and Co 3 O 4 particles were about 60, 5, and 10 nm, respectively. Reflection losses of graphene composites and pure graphene were systematically evaluated between 2 and 18 GHz, which revealed that all composites exhibited enhanced microwave absorption properties compared to pure graphene. The minimum reflection losses of MnO 2 -graphene, SnO 2 –graphene, and Co 3 O 4 –graphene composites with a thickness of 2.0 mm were −20.9, −15.28, and −7.3 dB at the frequency of 14.8, 15.94, and 9.6 GHz, respectively, whereas −4.5 dB for pure graphene. The enhanced absorption ability probably originated from the combined advantage of metal oxide particles and graphene, which proved beneficial to improve the impedance matching of permittivity and permeability. Besides, the intrinsic characteristics of MnO 2 , SnO 2 , and Co 3 O 4 nanoparticles, the interface between nanostructured metal oxides and graphene sheets, and the multi-dielectric relaxation processes are all influence factors to improve the properties of microwave absorption.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
MATERIALS RESEARCH INNOVATIONS
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2022
·
IF 0
Ye Wu,Wenyun Bao,Yibing Xie,Chen Yao
The well-controlled graphene was prepared by pre-oxidisation, full-oxidisation and hydrothermal reduction of flake graphite. The graphene oxide (GO) reveals the overlapped few-layer structure and the reduced graphene oxide (RGO) shows well-dispersed few-layer structure. Raman spectra analysis indicates that the RGO shows higher B band/G band ratio value than GO, indicating well-restored SP2 carbon atom arrangement and crystal structure. Both fewer-layer GO and RGO were coated on nickel form for supercapacitor electrode application. The GO with sufficient hydroxyl, epoxy and carboxyl groups reveals low conductivity and low current response, which causes low specific capacitance of 0.36, 0.38 and 0.55 F g−1 at 0.5 A g−1 in Na2SO4, KOH and LiOH electrolyte solution, respectively. The RGO with high conductivity reveals the enhanced specific capacitance of 37.12, 51.80 and 61.31 F g−1 at 0.5 A g−1. The LiOH electrolyte with superior ionic diffusion coefficient leads to higher capacitance performance of fewer-layer GO and RGO than other electrolytes. The RGO shows much higher current response than GO at the same scan rate in cyclic voltammetry measurement, which is ascribed to its higher electroactivity. The similar capacitance enhancement of RGO was achieved through cyclic voltammetry-based capacitance and galvanostatic charge/discharge-based capacitance measurements. Accordingly, fewer-layer RGO reveals the superior electrochemical capacitance performance in LiOH electrolyte for the effective energy-storage application.
研究领域:
材料科学
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能源存储
✓ 已验证
DOI
SYNTHETIC METALS
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2018
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IF 2.526
Sumin Wang,Lu Li,Qiguan Wang,Yaru Fan,Jingwen Shen,Kai Zhang,Lei Yang,Wenzhi Zhang
The surface of graphene (Gr) was covalently attached by an aniline oligomer, from the coupling of graphene oxide with aniline tetramer, followed by reduction process. After linked by tetramer aniline, the graphene materials showed remarkably enhanced electrochemical performances. The conductivity of the graphene was increased from 5.8 S cm −1 to 41.7 S cm ‒1 , under the strong doping effect between Gr and tetramer aniline by means of the π‒π interactions, which was analyzed by FT‒IR, UV–vis and XPS spectra. In addition, the aniline oligomer attached to reduced graphene oxide (AOAG) showed a remarkable energy-storage behavior due to the synergistic effect. The capacitance of AOAGs can be 370 F g −1 , while it is 114 F g −1 and 129 F g −1 for graphene oxide and tetramer aniline respectively. Because the covalent bonding between graphene and aniline oligomer can effectively combine the excellent mechanical strength of graphene and the large faradic pseudocapacitance of aniline oligomer, the AOAGs showed quite high charge-discharge cycle stability besides remarkable capacitance. In addition, the ease of electron motion mediated by the covalent bonding in AOAGs supports the sample significant electrochemical catalysis towards nifedipine. Compared with graphene and tetramer aniline, the oxidative current of nifedipine on AOAG showed five-fold increase.
研究领域:
材料科学
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电化学
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纳米技术
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DOI
高影响因子
SN Applied Sciences
·
2018
·Vol. 1
·期 1
·1-9
·
IF 0
Wei Q.,Wufuer A.,Wang M.,Wang Y.,Dai L.
Three-dimensional graphene (3DG) sponge has attracted increasing attention because it combines the unique properties of cellular materials and the excellent performance of graphene. Preparation of 3DG sponge depends mainly on the self-assembly of graphene oxide sheets. In the case of using uniform large graphene oxide and ultralarge graphene oxide sheets, the nematic liquid crystals (LCs) phases are formed at low concentration. After chemical reduction, the LCs of GO solution are converted to 3DG sponges with a high degree of orientation, offering a new methodology to regulate the controlled large GO sheets. The orientation of GO solution can be inherited by 3DG sponge, making the sponge to have a large-scale ordered network structure. The 3D elastic graphene sponges have low density and good elasticity, promising for the applications in strain sensing, shock damping, and energy cushioning. Our work explores a novel strategy for organizing the ordered alignment of controlled large GO sheets and exploring the relationship between the microstructures and mechanical properties of 3DG sponge.
研究领域:
材料科学
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纳米技术
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产品关联
DOI
Materials Today Communications
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2024
·
IF 3.7
Yangyang Zong,Dayong Gui,Kangmin Niu
There is a lack of systematic research on the use of liquid crystal-modified graphene in the production of thermally conductive composites. In this work, we utilized covalent and non-covalent interactions between 4′-allyloxy-biphenyl-4-ol (AOBPO) and graphene oxide (GO), reduced graphene oxide (rGO), and high-temperature reduced graphene oxide (GNS) to improve the compatibility and dispersion of the fillers with the silicone-cycloaliphatic epoxy resin. The thermal conductivity of GNS-AOBPO composite material significantly increases when a shear force field is applied, even at a lower filler content of 7 wt%, reaching 0.828 W/(m·K), which is 1.8 times higher than that without the field. At 9 wt% filler content, the thermal conductivity further increases to 1.161 W/(m·K), which is 10 times higher than epoxy resin. Concurrently, the electrical resistivity decreased by half. This provides a method for preparing thermal conductive composite materials by inducing the orientation of graphene through the application of a shear force field.
研究领域:
材料科学
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纳米技术
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复合材料
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产品关联
DOI
高影响因子
DESALINATION
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2025
·
IF 9.8
Ang Mi,Xinbo Qin,Fei Zhang,Rongping Yun,Youjing Zhao,Min Wang,Xu Xiang
Salt-lake brines have emerged as a promising source of lithium; however, the separation of Li + ions from other coexisting ions remains challenging. To surmount this issue, a three-dimensional wrinkled membrane that was based on a H 1.6 Mn 1.6 O 4 (HMO) ion sieve and comprised graphene oxide (GO) and hydroxylated graphene (GOH) was fabricated in this study. The designed structure provided abundant channels for ion migration. The hydroxyl groups of graphene allowed the membrane to exhibit improved Na + –Li + sieving ability. The lithium adsorption capacity of HMO-GOH/GO (20.6 mg/g) was considerably higher than that of HMO (8.9 mg/g) in a low-concentration lithium solution. The adsorption capacity and separation coefficient of HMO-GOH/GO in a high-sodium brine of Na/Li = 49:1 (48.0 mg/g and 47.1) were higher than those of HMO (21.6 mg/g and 29.3, respectively). The adsorption capacity of HMO-GOH/GO remained at 90.8 % of its initial value after 10 adsorption–desorption cycles, thus demonstrating excellent cyclic stability. HMO/GO-GOH shows higher specific capacitance than HMO based on the cyclic voltammetry results. The density functional theory calculations on adsorption energy of Li + ·4H 2 O and the energy barrier across the GOH pore confirm the Na + /Li + sieving capability. The adsorption mechanism was studied by in situ Raman spectroscopy, verifying the formation of Li O bond during lithium adsorption. Overall, this study provides guidance in the pursuit of a remedy for Na Li separation.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2020
·
IF 7.1
Xin Li,Wendou Feng,Xiangxin Zhang,Songyue Lin,Yuanqiang Chen,Chengwei Chen,Sujing Chen,Wei Wang,Yining Zhang
Monitoring the environmental humidity are of great significance to human comfort and product quality in many fields. However, high performance humidity sensors are difficult to be widely used because of their cost and complex preparation process. It is also highly desirable to develop a facile fabrication method that is capable of producing humidity sensors of customized size, shape, and geometry. Here, using a low power DVD drive, we successfully fabricate a highly sensitivity and low-cost humidity sensor, consisting of laser-scribed graphene (LSG) electrode and graphite oxide (GO) sensing layer. The LSG-GO humidity sensor operates in the relative humidity (RH) range of 19 %–97.4 %, demonstrating high sensitivity (4770.14 pF/% RH), quick response/recovery, and excellent sensing stability. In addition, the possible humidity sensing mechanism is discussed with the help of impedance spectroscopy. These results indicate that the LSG/GO sensor, enabled by the facile fabrication process with low power DVD drives, demonstrates promising potential with broad application prospects.
研究领域:
材料科学
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传感器技术
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环境监测
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Jiaming Wu,Zhengmao Ye,Wenxiu Liu,Zhifang Liu,Juan Chen
Ideal electromagnetic absorbing materials with lightweight and high efficiency have broad application outlook in military and civil fields. In this work, a 3D nanostructure material by hybridizing Fe 3 O 4 nanocrystals and reduced graphene oxide (Fe 3 O 4 /rGO) were synthesized through an environmental-friendly one-pot solvothermal method. The effect of GO loading on electromagnetic (EM) wave absorption characteristic of Fe 3 O 4 /rGO was investigated. The introduction of rGO sheets not only prevented Fe 3 O 4 from agglomerating, also improved the absorption performance of Fe 3 O 4 /rGO hybrids. With an appropriate addition, Fe 3 O 4 /rGO obtained a minimum reflection loss (RL) of −22.7 dB and the absorption bandwidth was 3.13 GHz (90% absorption).
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2015
·
IF 2.567
Rongrong Jiang,Xufeng Zhou,Qile Fang,Zhaoping Liu
Graphene nanosheets have shown great potential in enhancing the strength of metal composites. In previous researches, reduced graphene oxide (rGO) are usually used as the additive. Here, we demonstrate that pristine graphene (PG) prepared by intercalation and exfoliation of graphite, with negligible oxygen-containing functional groups, much less defects and higher electrical conductivity than rGO, exhibits better performance than rGO as additives for the enhancement of the strength of metal composites. Surface modification of PG and Cu was conducted to enhance the interaction between two components, resulting in homogeneous distribution of PG in Cu matrix. The PG/Cu composite exhibits yield strength σ 0.2 and 5% compression strength up to 172 and 228 MPa, respectively, which is a 90% and 81% promotion comparing to pure Cu, while its electrical conductivity still stays at 84.2% IACS. As to rGO/Cu composite, yield strength σ 0.2 and 5% compression strength is 156 and 208 MPa, respectively, and its electrical conductivity is 73.4% IASC. Such significant improvement on strength can be explained by the two-dimensional geometry and high crystallinity of PG whose high strength and modulus effectively constrain the movement of dislocations.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Materials Science and Engineering B-Advanced Functional Solid-State Materials
·
2023
·
IF 3.6
Wen Chen,Han Xiao,Liyin Hou,Xueyan Xu,Lina Kong,Xufeng Zhou,Zhaoping Liu
Graphene film has drawn great attention in flexible supercapacitors for its large specific surface area and high conductivity, but the trade-off between capacitance (positively correlated with structural defects) and electrical conductivity (negatively correlated with structural defects) still hinder its application. Herein, a graphene-based composite film is fabricated by cooperating graphene oxide with highly conductive graphene flakes. With the combined effect, graphene flakes endow the composite films with high electrical conductivity, while graphene oxide provides extra pseudocapacitance. The composite film shows a high specific capacitance of 191.1 F g −1 , which is far beyond that of pure graphene film (6.7 F g −1 ). The assembled flexible supercapacitor shows no capacitance decline when bent at different angles, and the capacitance retention of the supercapacitor keeps at 55.8% after 4500 bending-releasing cycles (0–180°). The excellent mechanical and electrochemical performance of reduced graphene oxide/graphene composite film makes it a promising candidate in flexible supercapacitors.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）