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graphene oxide

Qin Xiang, Yuping Liu, Xuefeng Zou, Bingbing Hu, Yujie Qiang, Danmei Yu, Wei Yin, Changguo Chen
In this work, g-C3N4@GO gel-like hybrid is obtained by assembling intentionally exfoliated g-C3N4 sheets on graphene oxide (GO) sheets under a hydrothermal condition. A specific N-doping process is firstly designed by heating the g-C3N4@GO interlaced hybrid in vacuum to form nitrogen-doped graphene nanosheets (NGS) with high level of pyridinic-N (56.0%) and edge-rich defect structure. The prepared NGS exhibited a great electrocatalysis for oxygen reduction reaction (ORR) in terms of the activity, durability, methanol tolerance, and the reaction kinetics...
March 16, 2018: ACS Applied Materials & Interfaces
Seiji Obata, Minoru Sato, Keishi Akada, Koichiro Saiki
A high throughput synthesis method of graphene has been required for a long time to apply graphene to industrial applications. Of the various synthesis methods, the chemical exfoliation of graphite via graphene oxide (GO) is advantageous as far as productivity is concerned; however, the quality of the graphene produced by this method is far inferior to that synthesized by other methods, such as chemical vapor deposition on metals. Developing an effective reduction and restoration method for GO on dielectric substrates has been therefore a key issue...
March 16, 2018: Nanotechnology
Tingting Liu, Shuo Wang, Qiuju Zhang, Liang Chen, Weihua Hu, Chang Ming Li
Ultrasmall ruthenium phosphide nanoparticles grown on reduced graphene oxide nanosheets (Ru2P/RGO-20) are reported as a highly efficient hydrogen evolution reaction (HER) catalyst. It achieves a current density of -10 mA cm-2 at extremely low overpotentials of -22 and -13 mV under acidic and alkaline conditions, respectively, superior to those of commercial Pt/C.
March 16, 2018: Chemical Communications: Chem Comm
Zhen Li, Shouzhen Jiang, Yanyan Huo, Tingyin Ning, Aihua Liu, Chao Zhang, Yuan He, Minghong Wang, Chonghui Li, Baoyuan Man
We report a three-dimensional (3D) SERS substrate with different numbers of silver nanoparticle (Ag NP) layers using multilayer graphene oxide (GO) as a spacer. The SERS performance of the 3D nanostructure was investigated and it was found that the SERS effect increased as the number of Ag NP layers increased, and showed almost no change for more than four layers. We found that the SERS performance of the 3D nanostructures can be mainly attributed to the topmost hot spots which are closely related to the Ag NP layers in the 3D nanostructure...
March 16, 2018: Nanoscale
Rafael Leite Rubim, Margarida Abrantes Barros, Thomas Missègue, Kévin Bougis, Laurence Navailles, Frédéric Nallet
Since the discovery of graphene oxide (GO), the most accessible of the precursors of graphene, this material has been widely studied for applications in science and technology. In this work, we describe a procedure to obtain GO dispersions in water at high concentrations, these highly dehydrated dispersions being in addition fully redispersible by dilution. With the availability of such concentrated samples, it was possible to investigate the structure of hydrated GO sheets in a previously unexplored range of concentrations, and to evidence a structural phase transition...
March 15, 2018: European Physical Journal. E, Soft Matter
Khairunnisa Amreen, Sivakumar Nisha, Annamalai Senthil Kumar
Direct sensing of uric acid (UA) in an undiluted whole blood sample is reported here taking human whole blood as an analyte and a self-supporting electrolyte. Among various solid electrodes (Pt, Au, GCE, and GCE/Nafion) and carbon nanomaterials (carbon nanofibers, graphene oxide, graphite nanopowder, graphitized mesoporous carbon (GMC), single-walled carbon nanotubes, and multiwalled carbon nanotubes) tested, a GMC-modified glassy carbon electrode, designated as GCE/GMC, showed a remarkable response towards direct electrochemical oxidation of blood uric acid at ∼0...
March 16, 2018: Analyst
Jing Li, Xiao Liang, Jun Zhang, Yunzhi Yin, Tiantian Zuo, Yiyue Wang, Xiaoming Yang, Qi Shen
In this study, heparin and polyethyleneimine-folic acid modified graphene oxide was designed and synthesized as a dual-targeting biomaterial to load doxorubicin (DOX@GPFH) with high loading capacity for enhanced cellular uptake. GDC0941, a phosphatidylinositide 3-kinase/Akt phosphorylation inhibitor, was selected to enhance anti-metastasis effect of DOX@GPFH via down-regulating expression of matrix metalloproteinase. Modified with heparin, the stability of DOX@GPFH was significantly enhanced and the drug loading ratio increased largely from 64...
March 12, 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
Ali Deniz Dalgic, Ammar Zeidan Alshemary, Ayşen Tezcaner, Dilek Keskin, Zafer Evis
In this study, novel graphene oxide-incorporated silicate-doped nano-hydroxyapatite composites were prepared and their potential use for bone tissue engineering was investigated by developing an electrospun poly(ε-caprolactone) scaffold. Nanocomposite groups were synthesized to have two different ratios of graphene oxide (2 and 4 wt%) to evaluate the effect of graphene oxide incorporation and groups with different silicate-doped nano-hydroxyapatite content was prepared to investigate optimum concentrations of both silicate-doped nano-hydroxyapatite and graphene oxide...
January 1, 2018: Journal of Biomaterials Applications
Wei Qian, Xiaodong Hu, Weifeng He, Rixing Zhan, Menglong Liu, Daijun Zhou, Yong Huang, Xiaohong Hu, Zhanhua Wang, Guoxia Fei, Jun Wu, Malcolm Xing, Hesheng Xia, Gaoxing Luo
Toward fabricating a novel multifunctional wound dressing material, we incorporated a series of contents of reduced graphene oxide (rGO) sheets into polydimethylsiloxane (PDMS) matrix to prepare the rGO-PDMS composite membrane and be used for wound dressing. The pore structure, dispersion of rGO, physical properties, water vapor transmission rate (WVTR), cytotoxicity and antibacterial activity were studied. Finally, the effect of the rGO-PDMS composite membrane on wound healing was investigated on a murine full-thickness skin wound model...
March 12, 2018: Colloids and Surfaces. B, Biointerfaces
Rensheng Cao, Mingyi Fan, Jiwei Hu, Wenqian Ruan, Xianliang Wu, Xionghui Wei
Highly promising artificial intelligence tools, including neural network (ANN), genetic algorithm (GA) and particle swarm optimization (PSO), were applied in the present study to develop an approach for the evaluation of Se(IV) removal from aqueous solutions by reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO) composites. Both GA and PSO were used to optimize the parameters of ANN. The effect of operational parameters (i.e., initial pH, temperature, contact time and initial Se(IV) concentration) on the removal efficiency was examined using response surface methodology (RSM), which was also utilized to obtain a dataset for the ANN training...
March 15, 2018: Materials
Zishen Wang, Qin'e Zhang, Shichuan Long, Yangxi Luo, Peikai Yu, Zhibing Tan, Jie Bai, Baihua Qu, Yang Yang, Jia Shi, Hua Zhou, Zong-Yuan Xiao, Wenjing Hong, Hua Bai
We apply direct ink writing for the three-dimensional (3D) printing of polyaniline/reduced graphene oxide (PANI/RGO) with PANI/GO gel as printable ink. The PANI/GO gel inks for 3D printing are prepared via self-assembly of PANI and GO in a blend solvent of N-methyl-2-pyrrolidinone and water, and offer both shaping capability, self-sustainability, and electrical conductivity after reduction of GO. Interdigitated electrodes are fabricated by using the PANI/GO ink in 3D printing, and a planar solid-state supercapacitor is constructed, which exhibits high performance with specific capacitance of 1329 mF cm-2...
March 15, 2018: ACS Applied Materials & Interfaces
Ayrat Dimiev, Vadim Neklyudov, Vera Agieienko, Marat Ziganshin
The self-association and solvation pattern of graphene oxide (GO) in water, ethylene glycol (EG) and their mixtures were analyzed by means of UV-Vis spectrophotometry. A careful analysis of the absorbance dependencies vs. the GO concentration shows that self-association of the GO sheets in EG occurs at higher concentration compared to that in water. It was established that depending on the mixed solvent composition two different types of the GO solvates are formed. The results of quantum chemical calculations allow one to suggest that in the water-rich compositions the GO oxygen containing groups are in direct contact with water molecules while in the glycol-rich media the EG molecules fully substitute water in the GO's first solvation layer...
March 15, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Eunji Kim, Hyeri Kim, Byung-Jun Park, Young-Hee Han, Jong Hyuk Park, Jinhan Cho, Sang-Soo Lee, Jeong Gon Son
From graphene oxide wrapped iron oxide particles with etching/reduction process, high-performance anode and cathode materials of lithium-ion hybrid supercapacitors are obtained in the same process with different etching conditions, which consist of partially etched crumpled graphene (CG) wrapped spiky iron oxide particles (CG@SF) for a battery-type anode, and fully etched CG for a capacitive-type cathode. The CG is formed along the shape of spikily etched particles, resulting in high specific surface area and electrical conductivity, thus the CG-based cathode exhibits remarkable capacitive performance of 210 F g-1 and excellent rate capabilities...
March 15, 2018: Small
Jing Ruan, Ying Wang, Fang Li, Renbing Jia, Guangming Zhou, Chunlin Shao, Liqi Zhu, Malin Cui, Da-Peng Yang, Shengfang Ge
Combination of drug chemotherapy and ray radiation is the main solution for treating patients with advanced colorectal carcinoma, but the toxicity and adverse effects caused in the surrounding normal tissues and the radio resistance in tumor site will severely influence its therapeutic effect. Nano radiosensitizer is an ideal choice for improving the tumor radiotherapy effects thanks to its high degree of tumor tissue uptake and secondary electrons productivity. Graphene quantum dots (GQDs) have good oxidative stress response and significantly high phototoxicity, and are regarded as a potential nano radiosensitizer...
March 15, 2018: ACS Applied Materials & Interfaces
Dongshuai Hou, Tiejun Yang, Jinhui Tang, Shaochun Li
Graphene oxide (GO) reinforced cement nanocomposites open up a new path for sustainable concrete design. In this paper, reactive force-field molecular dynamics was utilized to investigate the structure, reactivity and interfacial bonding of calcium silicate hydrate (C-S-H)/GO nanocomposite functionalized by hydroxyl (C-OH), epoxy (C-O-C), carboxyl (COOH) and sulfonic (SO3 H) groups with a coverage of 10%. The silicate chains in the hydrophilic C-S-H substrate provided numerous non-bridging oxygen sites and counter ions (Ca ions) with high reactivity, which allowed interlayer water molecules to dissociate into Si-OH and Ca-OH...
March 15, 2018: Physical Chemistry Chemical Physics: PCCP
Je Min Yoo, Baekwon Park, Sang Jin Kim, Yong Seok Choi, Sungmin Park, Eun Hye Jeong, Hyukjin Lee, Byung Hee Hong
Ferrous ion-based catalysts have been widely employed to oxidatively destruct the major industrial pollutants such as phenolic compounds through advanced oxidation processes (AOPs). These agents, however, inevitably show several drawbacks including the need for pH adjustment and further purification steps to remove residual salts. Here we report the use of a chemical vapour deposition (CVD) graphene film as a novel metal-free catalyst for the AOP-based degradation of phenols in aqueous solution, which does not require additional steps for salt removal nor external energy to activate the process...
March 15, 2018: Nanoscale
Giacomo Reina, Ngoc Do Quyen Chau, Yuta Nishina, Alberto Bianco
Several studies have demonstrated the ability of graphene oxide (GO) to efficiently adsorb small-interfering RNA (siRNA) on its surface and to transport it into cells. However, studies on whether and how siRNA interacts with GO are still inconclusive. In this context, understanding the interaction between GO and siRNA is fundamental to design new efficient gene silencing tools. In this work, the interactions between GO and siRNA molecules were systematically investigated. We focused on how the GO size, oxygenated groups present on the surface and chemical functionalization affect the double helix siRNA structure, using gel electrophoresis, UV-Vis spectroscopy, fluorescence resonance energy transfer (FRET) and circular dichroism (CD)...
March 15, 2018: Nanoscale
Katherine D Hills, Daniela A Oliveira, Nicholas D Cavallaro, Carmen L Gomes, Eric S McLamore
We demonstrate a sensing mechanism for rapid detection of Listeria monocytogenes in food samples using the actuation of chitosan-aptamer nanobrush borders. The bio-inspired soft material and sensing strategy mimic natural symbiotic systems, where low levels of bacteria are selectively captured from complex matrices. To engineer this biomimetic system, we first develop reduced graphene oxide/nanoplatinum (rGO-nPt) electrodes, and characterize the fundamental electrochemical behavior in the presence and absence of chitosan nanobrushes during actuation (pH-stimulated osmotic swelling)...
March 15, 2018: Analyst
Truong Thi Tuong Vi, Selvaraj Rajesh Kumar, Bishakh Rout, Chi-Hsien Liu, Chak-Bor Wong, Chia-Wei Chang, Chien-Hao Chen, Dave W Chen, Shingjiang Jessie Lue
In this work, silver nanoparticles (Ag NPs) were decorated on thiol (-SH) grafted graphene oxide (GO) layers to investigate the antibacterial activities in Gram-positive bacteria ( Staphylococcus aureus ) and Gram-negative bacteria ( Pseudomonas aeruginosa ). The quasi-spherical, nano-sized Ag NPs were attached to the GO surface layers, as confirmed by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The average size of GO-Ag nanocomposites was significantly reduced (327 nm) from those of pristine GO (962 nm) while the average size of loaded Ag NPs was significantly smaller than the Ag NPs without GO...
March 14, 2018: Nanomaterials
Mahmoud Nasrollahzadeh, Mohaddeseh Sajjadi, Fatemeh Ghorbannezhad, S Mohammad Sajadi
A3 coupling is one of the few transition-metal catalyzed carbon-carbon bond forming reactions that have been established as a most direct, efficient and atom-economical synthetic approach to afford propargylamine derivatives using various catalysts. A large number of nanosized heterogeneous catalysts for three-component coupling reactions between an aldehyde, an amine, and a terminal alkyne have been popularly introduced as an A3 coupling in the last decade. The coupling product has found a broad application as a key intermediate for a variety of heterocyclic useful compounds and numerous biologically active molecules such as β-lactams, conformationally restricted peptides, isosteres, herbicides, fungicides, indolizines, pyrroles, quinolines and therapeutic drug molecules...
March 14, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
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