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Core shell graphene oxide

Dong Sung Choi, Chanhoon Kim, Joonwon Lim, Su-Ho Cho, Gil Yong Lee, Ho Jin Lee, Jang Wook Choi, Heeyeon Kim, Il-Doo Kim, Sang Ouk Kim
Nanoscale materials offer enormous opportunities for catalysis, sensing, energy storage, and so on, along with their superior surface activity and extremely large surface area. Unfortunately, their strong reactivity causes severe degradation and oxidation even under ambient conditions and thereby deteriorates long-term usability. Here superlative stable graphene-encapsulated nanoparticles with a narrow diameter distribution prepared via in situ chemical vapor deposition (CVD) are presented. The judiciously designed CVD protocol generates 3 nm size metal and ceramic nanoparticles intimately encapsulated by few-layer graphene shells...
October 15, 2018: Advanced Materials
Zehui Li, Yuheng Jiang, Zhuoya Wang, Wenbo Wang, Yi Yuan, Xiaoxue Wu, Xingchen Liu, Mingjie Li, Sobia Dilpazir, Guangjin Zhang, Dongbin Wang, Chenming Liu, Jingkun Jiang
Core-shell structured particles were prepared from carbonized zeolitic imidazolate frameworks (ZIFs) and reduced graphene oxide (rGO). The particles possess a nitrogen content of up to 10.6%. The loss of nitrogen from the ZIF is avoided by utilizing the reduction and agglomeration of graphene oxide with suitable size (>2 μm) during pyrolysis. The resulting carbonized ZIF@rGO particles were deposited on a glassy carbon electrode to give an amperometric sensor for H2 O2 , typically operated at a voltage of -0...
October 9, 2018: Mikrochimica Acta
Liming Ren, Jun Dong, Zifang Chi, Huazheng Huang
Nanoscale zero-valent iron (nZVI) assembled on graphene oxide (GO) (rGO-nZVI) composites were synthesized by reduction of GO and ferrous ions with potassium borohydride, for use in Cr(VI) removal from aqueous solution. The results showed that the two-dimensional structure of GO could provide a skeleton support for Fe0 , thus overcoming the bottleneck of aggregation for nZVI. Also, rGO-nZVI would form a ferric-carbon micro-electrolysis system in Cr(VI)-contaminated aquifers, enhancing and accelerating electron transfer, exhibiting high rate and capacity for Cr(VI) removal...
November 2018: Journal of Environmental Sciences (China)
Ankita Hazarika, Biplab K Deka, Do-Young Kim, Hoon Eui Jeong, Young-Bin Park, Hyung Wook Park
Thermotherapy is a widespread technique that provides relief for muscle spasms and joint injuries. A great deal of energy is used to heat the surrounding environment, and heat emitted by the human body is wasted on our surroundings. Herein, a woven Kevlar® fiber (WKF)-based personal thermal management device was fabricated by directly growing vertical copper-nickel (Cu-Ni) nanowires (NWs) on the WKF surface using a hydrothermal method. The treated WKF was combined with reduced graphene oxide (rGO) dispersed in polydimethylsiloxane (PDMS) to form composites using vacuum-assisted resin transfer molding (VARTM)...
October 5, 2018: Nano Letters
Junnan Hao, Jian Zhang, Guanglin Xia, Yajie Liu, Yang Zheng, Wenchao Zhang, Yongbing Tang, Wei Kong Pang, Zaiping Guo
Recently, heterostructures have attracted much attention in widespread research fields. By tailoring the physicochemical properties of the two components, creating heterostructures endows composites with diverse functions due to the synergistic effects and interfacial interaction. Here, a simple in situ localized phase transformation method is proposed to transform the transition-metal oxide electrode materials into heterostructures. Taking molybdenum oxide as an example, quasi-core-shell MoO3 @MoO2 heterostructures were successfully fabricated, which were uniformly anchored on reduced graphene oxide (rGO) for high-rate and highly durable lithium ion storage...
September 28, 2018: ACS Nano
Fanjun Zhu, Guangying Zhao, Wenchao Dou
A highly sensitive electrochemical sandwich immunoassay is described for determination of Escherichia coli O157:H7 (E. coli O157:H7). Silica coated magnetite nanoparticles (Fe3 O4 ) were modified with primary antibody to capture E. coli O157:H7. Gold-platinum core/shell nanoparticles (Au@Pt NPs) with different Pt shell thicknesses were prepared via changing the molar ratio of H2 PtCl6 to HAuCl4 in the precursor solution. The optimized Au@Pt NPs exhibit enhanced activity in the electrocatalytic reduction of hydrogen peroxide (H2 O2 )...
September 13, 2018: Mikrochimica Acta
Kexin Zhang, Chong Qu, Zibin Liang, Song Gao, Hao Zhang, Bingjun Zhu, Wei Meng, Engang Fu, Ruqiang Zou
Oxygen reduction and evolution reactions as two important electrochemical energy conversion processes in metal-air battery devices have aroused widespread concern. However, synthesis of low-cost non-noble metal-based bifunctional high-performance electrocatalysts is still a great challenge. In this work, we report on the design and synthesis of a novel Co-B/N codoped carbon with core-shell-structured nanoparticles aligned on graphene nanosheets (denoted as CoTIB-C/G) derived from cobalt tetrakis(1-imidazolyl)borate (CoTIB) and graphene oxide hybrid template...
September 12, 2018: ACS Applied Materials & Interfaces
Jing Zhao, Ning Fu, Rui Liu
Development of high-performance nonprecious metals and their nanocomposites as oxygen reduction electrocatalysts is critical but still challenging for fuel cells and metal-air batteries. Here, we introduce a synthetic strategy to fabricate graphite-wrapped Fe core-shell nanoparticles anchored on graphene as an efficient and stable pH-universal electrocatalyst for oxygen reduction reaction (ORR). The coordination among Fe3+ , ellagic acid, and graphene oxide would drive the formation of a sandwichlike assembly, which was subsequently converted into graphene-supported Fe@graphitic carbon core-shell nanoparticles (denoted as GEF)...
August 29, 2018: ACS Applied Materials & Interfaces
Jianyang Li, Shun Mao, Yang Hou, Lecheng Lei, Chris Yuan
The design of highly active, stable, and low-cost oxygen reduction reaction (ORR) electrocatalysts to replace platinum-based materials is crucial to the development of renewable energy technologies. Herein, novel 3D edge-enriched Fe3 C@C nanocrystals with a core-shell structure grown on reduced graphene oxide (rGO) networks (Fe3 C@C/rGO) are reported as highly efficient and stable electrocatalysts for the ORR. The rGO nanosheets act as a host and provide vital support for local growth of edge-enriched Fe3 C@C nanocrystals, leading to a large surface area of 263 m2  g-1 and superstable hybrid structure...
July 23, 2018: ChemSusChem
Qi Zhang, Qin Luo, Zhenbo Qin, Lei Liu, Zhong Wu, Bin Shen, Wenbin Hu
Cu has recently received great interest as a potential candidate for glucose sensing to overcome the problems with noble metals. In this work, reduced graphene oxide-encapsulated Cu nanoparticles (Cu@RGO) have been prepared via an electrostatic self-assembly method. This core/shell composites were found to be more stable than conventional Cu-decorated graphene composites and bare copper nanoparticles in an air atmosphere because the graphene shell can effectively protect the Cu nanoparticles from oxidation...
March 31, 2018: ACS Omega
Linlin Li, Yonghua Yuan, Yongjie Chen, Pu Zhang, Yan Bai, Lijuan Bai
The 6-kDa early secretory antigenic target referred to as ESAT-6 is a virulence factor secreted by Mycobacterium tuberculosis (MTB). This work describes a voltammetric aptasensor for ultrasensitive detection of ESAT-6. Reduced graphene oxide doped with metal-organic framework (MOF-rGO) was deposited on a glassy carbon electrode (GCE). This increases the immobilization of electroactive Toluidine Blue (TB) and facilitates the electron transfer from TB to the modified GCE. Platinum/gold core/shell (Pt@Au) nanoparticles were used to assemble thiolated ESAT-6 binding aptamer (EBA) on a modified electrode and to further amplify the response to TB...
July 17, 2018: Mikrochimica Acta
Mengbin Gu, Qian Sui, Usman Farooq, Xiang Zhang, Zhaofu Qiu, Shuguang Lyu
Nano zero-valent iron (nZVI) particles with higher reactivity have been recognized as more efficient catalysts than Fe(II) for the groundwater remediation. The rapid emergence of novel catalyst supports efficiently prevent the rapid aggregation of nZVI and further improve catalytic reactivity. However, the lack of ability to avoid the potential oxidation of bare nZVI-support structure in air environment hinders its wider application in the actual contaminated sites. In this study, nZVI on reduced graphene oxide (rGO) functionalized by polydopamine (PDA) (nZVI-PDA@rGO) was synthesized successfully and applied into sodium persulfate (SPS), potassium monopersulfate (PMS) and H2 O2 oxidative environments to remove trichloroethylene (TCE)...
July 9, 2018: Journal of Hazardous Materials
Artur Khannanov, Airat Kiiamov, Alina Valimukhametova, Dmitrii A Tayurskii, Felix Börrnert, Ute Kaiser, Siegfried Eigler, Farit G Vagizov, Ayrat M Dimiev
Stabilizing nanoparticles on surfaces, such as graphene, is a growing field of research. Thereby, iron particle stabilization on carbon materials is attractive and finds applications in charge-storage devices, catalysis, and others. In this work, we describe the discovery of iron nanoparticles with the face-centered cubic structure that was postulated not to exist at ambient conditions. In bulk, the γ-iron phase is formed only above 917 °C, and transforms back to the thermodynamically favored α-phase upon cooling...
July 25, 2018: Journal of the American Chemical Society
Shuang Guo, Yaxin Wang, Fan Zhang, Renxian Gao, Maomao Liu, Lirong Dong, Yang Liu, Yongjun Zhang, Lei Chen
Emerging opportunities based on two-dimensional (2D) layered structures can utilize a variety of complex geometric architectures. Herein, we report the synthesis and properties of a 2D+0D unique ternary platform-core-shell nanostructure, termed Ag@Cu₂O-rGO, where the reduced graphene oxide (rGO) 2D acting as a platform is uniformly decorated by Ag@Cu₂O core-shell nanoparticles. Cu₂O nanoparticles occupy the defect positions on the surface of the rGO platform and restore the conjugation of the rGO structure, which contributes to the significant decrease of the I D / I G intensity ratio...
June 17, 2018: Nanomaterials
Ziliang Chen, Renbing Wu, Yang Liu, Yuan Ha, Yanhui Guo, Dalin Sun, Miao Liu, Fang Fang
The rational design of an efficient and inexpensive electrocatalyst based on earth-abundant 3d transition metals (TMs) for the hydrogen evolution reaction still remains a significant challenge in the renewable energy area. Herein, a novel and effective approach is developed for synthesizing ultrafine Co nanoparticles encapsulated in nitrogen-doped carbon nanotubes (N-CNTs) grafted onto both sides of reduced graphene oxide (rGO) (Co@N-CNTs@rGO) by direct annealing of GO-wrapped core-shell bimetallic zeolite imidazolate frameworks...
July 2018: Advanced Materials
Akram Assali, Omid Akhavan, Mohsen Adeli, Shayan Razzazan, Rassoul Dinarvand, Saeid Zanganeh, Masoud Soleimani, Meshkat Dinarvand, Fatemeh Atyabi
Recent insights into the nanomedicine have revealed that nanoplatforms enhance the efficacy of carrier in therapeutic applications. Here, multifunctional nanoplatforms were utilized in miRNA-101 delivery and NIR thermal therapy to induce apoptosis in breast cancer cells. Au nanorods (NRs) or nanospheres (NSs) covered with graphene oxide (GO) were prepared and functionalized with polyethylene glycol as a stabilizer and poly-L-arginine (P-L-Arg) as a targeting agent. In nanoplatforms, coupling Au@GO prepared stable structures with higher NIR reactivity...
August 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
Dan Li, Jisheng Zhou, Xiaohong Chen, Huaihe Song
Designing transitional metal selenides (TMSes) with superior rate and cyclic performance for sodium-ion storage remains great challenges. To achieve this task, the influence of surface oxides on Na-ion storage behavior of FeSe2 is investigated by designing FeSe2 with varying oxide content. It is found that surface oxide has an inhibitory effect on the activity of FeSe2 . Small-sized FeSe2 on graphene with higher surface oxide content exhibits obviously inferior performance compared to large-sized FeSe2 with lower oxide content...
July 5, 2018: ACS Applied Materials & Interfaces
Tran Dinh Minh, Byeong-Kyu Lee
1H-Benzo[d]imidazole (BMA) has been considered as an emerging pharmaceutical organic contaminant, leading to the increasing BMA detection in wastewaters and need to be removed from ecosystem. This study investigated a highly synergistic BMA chemisorption using a novel ternary cross-coupled nanohybrid [γ-APTES]-Fe3 O4 @PAN@rGO. Magnetic nanoparticles (Fe3 O4 ) were in situ core-shell co-precipitated with polyacrylonitrile polymer (PAN). Then, the prepared Fe3 O4 @PAN was decorated on hexagonal arrays of reduced graphene oxide (rGO) inside the framework of γ-aminopropyltriethoxysilane ([γ-APTES])...
August 2018: Environmental Science and Pollution Research International
Wentong Zhao, Xiaoqing Lu, Manickam Selvaraj, Wei Wei, Zhifeng Jiang, Nabi Ullah, Jie Liu, Jimin Xie
Low-cost electrocatalysts play an important role in the hydrogen evolution reaction (HER). Particularly, transition metal phosphides (TMPs) are widely applied in the development of HER electrocatalysts. To improve the poor electrochemical reaction kinetics of HER, we introduce a facile way to synthesize carbon core-shell materials containing cobalt phosphide nanoparticles embedded in different graphene aerogels (GAs) (CoP@C-NPs/GA-x (x = 5, 10 and 20)) using seaweed biomass as precursors. The synthesized CoP@C-NPs/GA-5 exhibits efficient catalytic activity with small overpotentials of 120 and 225 mV at current densities of 10 mA cm-2, along with the low Tafel slopes of 57 and 66 mV dec-1, for HER in acidic and alkaline electrolytes, respectively...
May 24, 2018: Nanoscale
Shiting Wu, Mingchu Zou, Zhencheng Li, Daqin Chen, Hui Zhang, Yongjun Yuan, Yongmao Pei, Anyuan Cao
Cu nanowires (CuNWs) are considered as a promising candidate to develop high performance metal aerogels, yet the construction of robust and stable 3D porous structures remains challenging which severely limits their practical applications. Here, graphene-hybridized CuNW (CuNW@G) core-shell aerogels are fabricated by introducing a conformal polymeric coating and in situ transforming it into multilayered graphene seamlessly wrapped around individual CuNWs through a mild thermal annealing process. The existence of the outer graphene shell reinforces the 3D bulk structure and significantly slows down the oxidation process of CuNWs, resulting in improved mechanical property and highly stable electrical conductivity...
June 2018: Small
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