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Core shell graphene oxide

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 batteries 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 co-doped 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...
August 13, 2018: ACS Applied Materials & Interfaces
Jing Zhao, Ning Fu, Rui Liu
Development of high-performance non-precious 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 sandwich-like assembly, which was subsequently converted into graphene supported Fe@graphitic carbon core-shell nanoparticles (denoted as GEF)...
August 3, 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...
June 10, 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
Syam Kandula, Khem Raj Shrestha, Nam Hoon Kim, Joong Hee Lee
Supercapacitors suffer from lack of energy density and impulse the energy density limit, so a new class of hybrid electrode materials with promising architectures is strongly desirable. Here, the rational design of a 3D hierarchical sandwich Co9 S8 /α-MnS@N-C@MoS2 nanowire architecture is achieved during the hydrothermal sulphurization reaction by the conversion of binary mesoporous metal oxide core to corresponding individual metal sulphides core along with the formation of outer metal sulphide shell at the same time...
June 2018: Small
Shou-Heng Liu, Jun-Sheng Lu, Sheng-Wei Yang
The rhombic dodecahedral cuprous oxide-reduced graphene oxide/core-shell Fe3 O4 @SiO2 composites (denoted as rCu2 O-rGO/Fe3 O4 @SiO2 ) are successfully synthesized facilely via a wet-chemical route. The resulting rCu2 O-rGO/Fe3 O4 @SiO2 combines the unique structure of Cu2 O, electronic characteristics of reduced graphene oxide (rGO) and magnetic property of Fe3 O4 @SiO2 to be an effective and recoverable photocatalyst for the degradation of methyl orange (MO). The obtained results show that rCu2 O-rGO/Fe3 O4 @SiO2 is capable of completely degrading MO in the presence of a very low catalyst concentration (0...
July 27, 2018: Nanotechnology
Ajay Kumar, Kumbam Lingeshwar Reddy, Suneel Kumar, Ashish Kumar, Vipul Sharma, Venkata Krishnan
Utilization of the total solar spectrum efficiently for photocatalysis has remained a huge challenge for a long time. However, designing a system by rationally combining nanocomponents with complementary properties, such as upconversion nanoparticles, semiconductors, plasmonic metals, and carbonaceous support, offers a promising route for efficient utilization of solar energy by harnessing the broadband spectrum. In this work, a series of novel quaternary plasmonic photocatalysts comprising of lanthanide-doped NaYF4 @CdS (UC) core-shell nanostructures decorated with Au nanoparticles (Au NPs) supported on reduced graphene oxide (RGO) nanosheets were prepared using the multistep hydrothermal method...
May 9, 2018: ACS Applied Materials & Interfaces
Tian Gan, Zhikai Wang, Zhaoxia Shi, Dongyun Zheng, Junyong Sun, Yanming Liu
In this study, a facile solution approach was developed for the synthesis of a series of core-shell structured Ag@Cu2 O nanocrystals of various shapes including triangles, spheres, and cubes with well-defined stable heterojunctions. The electrooxidation of dopamine (DA), uric acid (UA), guanine (G), and adenine (A) using these hybrids revealed morphology-dependent sensing properties, with activities and accumulation ability following the order, triangular Ag@Cu2 O > spherical Ag@Cu2 O > cubic Ag@Cu2 O...
July 30, 2018: Biosensors & Bioelectronics
Corinne J Hofer, Robert N Grass, Elia M Schneider, Lyndsey Hendriks, Antoine F Herzog, Martin Zeltner, Detlef Günther, Wendelin J Stark
Selective dealloying of metal nanoparticles results in rattle-type hollow carbon nanoshells enclosing platinum nanoparticles, which are able to perform size-selective catalysis. Selective functionalization of the outer graphene-like carbon surface prevents agglomeration and leads to well dispersible nanocatalysts in aqueous solutions. The synthesis starts with the production of nanoparticles with a cobalt-platinum-alloy core surrounded by graphene-like carbon via reducing flame spray synthesis. After surface functionalization, simultaneous pore formation in the shell-wall and dissolution of the cobalt results in platinum encapsulated in hollow carbon nanospheres...
January 14, 2018: Chemical Science
Rong-Mei Kong, Aijun Yang, Qin Wang, Youjuan Wang, Lin Ma, Fengli Qu
The authors describe a fluorescent "turn-on" assay for detection of uric acid (UA) based on the use of graphene quantum dots coated with a shell of silver (GQD@Ag). The fluorescence of the GQDs is quenched by the silver shell. However, if the silver shell was removed via etching with H2 O2 (which is produced by uricase catalyzed oxidation of UA), the fluorescence of the GQDs is restored. The resulting increase in fluorescence at 466 nm depends directly on the concentration of H2 O2 , which, in turn, depends on the concentration of UA...
December 18, 2017: Mikrochimica Acta
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