Journal of Nanomaterials
·
2019
·Vol. 2019
·期 1
·5290496
·
IF 2.233
Zhenzhu Yu,Fei Nan,Lu Su,Shaofei Zhang,Yan He
Intercalation and exfoliation are key steps in the preparation of graphene by thermal exfoliation, and they determine the quality of the final product. Therefore, it is important to explore the influence of intercalation agents on the intercalation and exfoliation of graphite. In this article, ammonium bicarbonate is intercalated into graphite with different degrees of oxidation to form a graphite intercalation compound (GIC) by means of ultrasound and stirring. Then, they are exfoliated by being heated at high temperatures. After ammonium bicarbonate intercalation and heating treatment, XRD, TG, and BET show that the intercalation and exfoliation effect of graphite oxide (GO) is better than that of graphite (G) and expanded graphite (EG). The intercalation mechanism is that the ammonia molecule in ammonium bicarbonate solution contains a wedge-shaped structure and active point, which provides empty orbits for graphite electrons and forms edge intercalation through physical interaction at the same time.
研究领域:
材料科学
·
纳米材料
·
物理化学
·
碳材料
·
功能材料
✓ 已验证
DOI
高影响因子
CARBON
·
2024
·
IF 10.5
Ping He,Yu Zhang,Zhenguo Wang,Peng Min,Zhiming Deng,Lulu Li,Lvxuan Ye,Zhong-Zhen Yu,Hao-Bin Zhang
Graphene has been widely studied for its excellent properties of outstanding conductivity, strength , and flexibility. However, interlayer defects formed during the macroscopic assembly of graphene nanosheets will severely degrade the performance of graphene films. Herein, a strategy combined with trace carboxyl graphene oxide (GO), mild reduction, and chemical crosslinking is employed to minimize the interlayer defects for enhancing both the conductivity and mechanical strength of graphene films. The trace carboxyl feature of GO allows nanosheets to assemble orderly into highly oriented GO films . Subsequently, the mild chemical reduction preserves the highly oriented and packed microstructure. Coupling with further crosslinking by introducing conjugated molecules with pyrene terminal groups (1-pyrene butyric acid-1,6-hexane diamine, PHD) to provide extra π-π bonds, both the mechanical strength and conductivity of graphene films are improved to 548.4 MPa and 1.7 × 10 5 S m −1 , respectively. In addition, the graphene film with only ∼2 μm in thickness possesses an excellent electromagnetic interference shielding effectiveness (EMI SE) of ∼40 dB and a specific shielding effectiveness of up to 74 278 dB cm 2 g −1 in a wide frequency range of 8.2–40.0 GHz. Thus, this study provides an energy-saving fabrication route for mechanically strong, effective thermal management and EMI shielding films.
研究领域:
材料科学
·
纳米科技
·
高分子化学
·
功能材料
·
电磁屏蔽
·
热管理
✓ 已验证
DOI
高影响因子
CARBON
·
2013
·
IF 5.868
Xiuqing Meng,Sefaattin Tongay,Jun Kang,Zhanghui Chen,Fengmin Wu,Shu-Shen Li,Jian-Bai Xia,Jingbo Li,Junqiao Wu
ZnMg and NbCl 5 were intercalated in graphite and the presence of such molecules between the graphene sheets results in n- and p-type doping, respectively. The doping effect is confirmed by Hall and Raman measurements and the intercalation process is monitored by scanning tunneling microscopy . After intercalation the carrier concentration increase almost an order of magnitude and reaches values as high as 10 19 and 10 18 cm −3 for p- and n-type doping, respectively. For higher intercalation times, the intercalated graphite turns back to be as ordered as pristine one as evidenced by the reduction in the D peak in Raman measurements. Intercalation compounds show remarkable stability allowing us to permanently tune the physical properties of few-layer graphite. Our study has provided a new route to produce stable and functional graphite intercalation compounds and the results can be applied to other graphitic structures such as few-layer graphene on SiC.
研究领域:
凝聚态物理
·
材料科学
·
纳米科技
·
表面科学
·
半导体物理
✓ 已验证
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2011
·Vol. 30
·期 1
·112-117
·
IF 5.361
Huanshun Yin,Yunlei Zhou,Xiaomeng Meng,Kun Shang,Shiyun Ai
The graphene nanosheets and carbon nanospheres mixture (GNS–CNS) was prepared by electrolyzing graphite rob in KNO 3 solution under constant current, which was characterized by TEM, AFM, SEM, FT-IR, XRD, XPS, TGA and UV–vis. The nano-mixture can keep stable in water for more than one month. Based on this kind of mixture material, a novel electrochemical biosensing platform for glucose determination was developed. Cyclic voltammetry of glucose oxidase (GOD) immobilized on GNS–CNS/GCE exhibited a pair of well-defined quasi-reversible redox peaks at −0.488 V ( E pa ) and −0.509 V ( E pc ) by direct electron transfer between the protein and the electrode. The charge-transfer coefficient ( α ) was 0.51, the electron transfer rate constant was 2.64 s −1 and the surface coverage of HRP was 3.18 × 10 −10 mol cm −2 . The immobilized GOD could retain its bioactivity and catalyze the reduction of dissolved oxygen. The glucose biosensor has a linear range from 0.4 to 20 mM with detection limit of 0.1 mM. Moreover, the biosensor exhibits acceptable reproducibility and storage stability. The fabricated biosensor was further used to determine glucose in human plasma sample with the recoveries from 96.83% to 105.52%. Therefore, GOD/GNS–CNS/GCE could be promisingly applied to determine blood sugar concentration in the practical clinical analysis.
研究领域:
分析化学
·
纳米生物技术
·
电化学传感
·
生物医学工程
·
临床检验
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 27
·期 7
·7265-7273
·
IF 1.798
Zhang Dongjiu,Cheng Haifeng,Zhang Zhaoyang,Kang Yue
This paper introduced a general method of etching suspended graphene by nonmetallic SiO x nanoparticles (SiO x NPs) in graphene synthesis. Effects of etching time, concentration of silica gel and type of graphene on the etching mode of graphene have been systematically considered with using as-grown graphene film on a silica gel coating copper as model system. Nonmetallic SiO x NPs acted as etchant plays important role in the in situ etching process during the fabrication of graphene. The etched multilayer graphene pattern can be modulated from large area films to a rectangle pattern by varying the Si concentration and etching time, while single layer graphene pattern alters little. The morphology and critical structure of SiO x etched graphene were characterized by Raman spectra, transmission electron microscopy, scanning electron microscope and X-ray photoelectron spectrum. The process and mechanism described here open the way for tailoring graphene via nanoparticles instead of metal, which show significant influence of the electrical properties of graphene.
研究领域:
纳米材料学
·
表面科学
·
凝聚态物理
·
材料化学
·
电子显微学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Jun Rao,Hui Gao,Ying Guan,Wen-qi Li,Qiang Liu
An effective and green method to incorporate graphene oxide into quaternized hemicelluloses to form a hemicelluloses based film was introduced in this study. Tight, homogeneous, and smooth surfaces of the film were obtained from the SEM image. Data on the mechanical properties of the films indicated that the hybrid films prepared from QH and GO (component of GO was 4.8%) exhibited a high tensile strength of 43.83 MPa. This finding suggested that addition of GO contributed to the desirable mechanical properties of the hybrid film. The hybrid films exhibited high sensitivity to humidity; they could be bent spontaneously under wet conditions within seconds and stretched under dry conditions. In addition, the results of DMA indicated that the storage modulus of the hybrid films had an order of magnitude change in value at different humidities. These characteristics show that films can be potentially used in bio-medicine, packaging materials, and humidity sensors.
研究领域:
材料科学
·
生物医学工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 43
·49320
·
IF 2.52
Zhenggang Luo,Huijian Ye,Jiawei Hu,Te Hu,Boyuan Zhang,Xuanhe Zhang,Lixin Xu
A strategy for preparing ethylene-vinyl acetate (EVA)/graphene nanocomposites from liquid-phase exfoliated graphene has been explored with the use of a pyrene-functionalized hyperbranched polyethylene (HBPE) ternary copolymer, HBPE@Py@PMA, as stabilizer for graphite exfoliation. The HBPE@Py@PMA was synthesized by combining the Pd-diimine-catalyzed chain walking ternary ethylene copolymerization and atomic transfer radical polymerization techniques and has been confirmed to possess a HBPE core simultaneously bearing pyrene terminal groups and polymethacrylate side chains. As stabilizer, it is found to effectively promote graphite exfoliation in CHCl 3 to render high-quality few-layer graphene with an efficiency as high as 43%. Meanwhile, it can be steadily adsorbed on the exfoliated graphene surface to concurrently render functionalized graphene well dispersible in EVA matrix with strong interfacial interactions. This allows us to obtain EVA/graphene nanocomposites from resulting graphene dispersion through simple solution mixing process. By adding only 0.5 wt% of graphene, the dielectric constant of resulting composite increases by 55% compared to pure EVA, with a dielectric loss only 0.012. The role mechanism of the HBPE@Py@PMA for promoting graphite exfoliation in CHCl 3 and the formation of EVA/graphene nanocomposites from the resulting graphene has been proposed.
研究领域:
高分子化学
·
纳米复合材料
·
材料科学
·
胶体与界面化学
·
功能高分子
✓ 已验证
DOI
高影响因子
SOLAR ENERGY
·
2018
·
IF 4.374
Xiuli Wang,Xiaomin Cheng,Yuanyuan Li,Ge Li,Jun Xu
A self-assembly method is introduced to prepare composite phase change materials (PCMs) consisting of 1-octadecanol (OD) and graphene. The shape stability and thermal properties of 1-octadecanol/graphene composite PCMs with three-dimensional network structure are investigated. Graphene is dispersed evenly in OD matrix and the three-dimensional network structure is getting tighter with increasing ratio of graphene. OD is completely encapsulated at relatively low amount of graphene about 1.5 wt%. XRD and Raman results show that the combination between OD and graphene is physical adsorption. The 1-octadecanol/graphene (OG) composite phase change materials possess excellent shape stability, which can prevent the leakage of molten OD during phase transition. In addition, around 99.3% phase change enthalpy of pure OD is maintained by connected network structure of graphene while the melting and solidifying temperature merely have small fluctuations. The thermal conductivity of composite phase change material with 1.5 wt% graphene increases to 0.358 W/(m K), which is 1.5 times higher than that of pure OD. Furthermore, the porous network of graphene can delay the evaporation and thermal decomposition point of the composite phase change materials, thus extending the operating temperature of OD efficiently. This work provides a promising way to encapsulate low-temperature organic phase change materials with little carbon additives, and enhance the thermophysical properties of base materials simultaneously.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·Vol. 15
·期 3
·2528-2538
·
IF 1.5
Wenhui Geng,Mengmeng Zheng,Dan Chen,Xianwen Wang,Zekai Zhang,Yishan Lin,Dongqin Cai,Huiqin Li,Guobo Huang,Yanxian Jin Yu,Binbin Yus
Palladium catalyst (Pd) are made attention to application in alcohol fuel cells due to unique performance, as well as the resource abundance and low cost, but the catalyst performance and stability of the catalysts are still not satisfied. In this article, the novel PdFe/B-N-G catalysts with the double element alloying and dual-doping for ethanol electro-oxidation are successfully prepared and determined by XRD, TEM and XPS. TEM results reveal a relatively uniform and high dispersion of Pd particles is observed on PdFe/B-N-G catalyst. The XPS analysis indicates that Pd(0) contents of the PdFe/B-N-G catalyst are increased on account of the B, N-doping effect. Being explored as the catalyst to the ethanol oxidation reactions, the PdFe/B-N-G catalysts exhibit the better electrocatalytic activity with higher current densities and catalyst stability compared to those of PdFe/G and Pd/B-N-G, which can be attributed to the synergistic effect of the enhanced PdFe alloying and the B, N-doping, that can produce more activity sites dispersing on the surface of graphene. Thus, the novel PdFe/B-N-G catalysts can be the potential alternate in alcohol fuel cells.
研究领域:
电化学
·
纳米催化
·
能源材料
·
燃料电池
·
表面科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2013
·Vol. 4
·期 5
·2550-2556
·
IF 2.562
Liuting Zhang,Xuezhang Xiao,Xiulin Fan,Shouquan Li,Hongwei Ge,Qidong Wang,Lixin Chen
A simple approach to dramatically enhance the dehydrogenation properties of sodium borohydride is achieved by ball milling NaBH4 with fluorographite (FGi). It was found that the ball-milled NaBH4–FGi composite starts to release hydrogen without impurity gas at a lower temperature of 125 °C, and obtains a hydrogen desorption capacity of ca. 4.8 wt% below 130 °C in seconds, which is improved markedly compared to the ball-milled pristine NaBH4. The significant thermodynamic and kinetic improvement of the NaBH4–FGi composite can be ascribed to the reaction between NaBH4 and FGi as well as the formation of micro-scale NaBH4. Moreover, since the dehydrogenation process of NaBH4–FGi composite is exothermal, the fully reverse reaction is not feasible. In-depth investigations show that the partial rehydrogenation is due to the formation of Na2B12H12 and another new borohydride.
研究领域:
材料科学
·
能源化学
·
纳米科技
·
物理化学
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2018
·
IF 0
Lu Shen,Yong Li,Wenjie Zhao,Lijing Miao,Weiping Xie,Huanming Lu,Kui Wang
In order to hold the excellent corrosion resistance of zinc-rich epoxy coatings with reduced zinc content, five types of graphene modified zinc-rich epoxy coatings (G-ZRCs) were prepared. The effect of zinc content on the corrosion protection behaviors of G-ZRCs was investigated using electrochemical impedance spectroscopy (EIS). Open circuit potential (OCP) was also utilized to deepen the understanding of the anticorrosion mechanism of the as-prepared composite coatings. The results confirmed that addition of 0.3 wt % graphene could make the coating with 40 wt % (G-40ZRC) and 55 wt % zinc (G-55ZRC) provide cathodic protection for a short period of time. The EIS and OCP results showed a dominant physical barrier protection mechanism for the coatings without zinc (G-ZRC), while there was a mixed mechanism for G-40ZRC and G-55ZRC and a dominant cathodic protection mechanism for the coatings with 70 and 85 wt % zinc (G-70ZRC and G-85ZRC). Furthermore, the graphene modified zinc-rich coatings and corresponding corrosion products immersed in a 3.5% NaCl solution for 100 days were also characterized, which could further reveal anticorrosion mechanisms of the graphene modified zinc-rich coatings and the passivation effect of polyaniline (PANI).
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Mingli Zhang,Hengcong Tao,Yongchao Liu,Chao Yan,Song Hong,Justus Masa,Alex W. Robertson,Shizhen Liu,Jieshan Qiu,Zhenyu Sun
Development of naturally abundant, low cost, and energy-efficient electrocatalysts for the oxygen reduction reaction (ORR) is essential for commercialization of fuel cells. In this work, we report simple ultrasonication assisted synthesis of nitrogen and boron dual-doped graphene oxide (NB/GO) and demonstrate its application as an effective ORR catalyst realizing predominantly 4e– reduction of O2 to OH– in 0.1 M KOH. Enhanced ORR electrocatalysis of the dual B and N codoped GO as opposed to GO singly doped with B or N arises from the synergistic interaction of the boron and nitrogen species. The content and configuration of both N and B dopants can be readily tailored by controlling the ultrasonic conditions, thereby permitting tuning of the ORR activity. Furthermore, the developed NB/GO metal-free catalyst exhibited very promising long-term durability and resistance to methanol poisoning compared to the state-of the art Pt/C catalyst.
研究领域:
材料科学
·
电化学
·
能源技术
✓ 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）