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Graphen Oxide

Samanta Witomska, Włodzimierz Czepa, Zhaoyang Liu, Alessandro Aliprandi, Dawid Pakulski, Piotr Pawluc, Artur Ciesielski, Paolo Samorì
Towards the introduction of fast faradaic pseudocapacitive behavior and the increase of the specific capacitance of carbon-based electrodes, we have covalently functionalized graphene oxide with a redox active thiourea-formaldehyde polymer yield-ing a multifunctional hybrid system. The multiscale physical and chemical characterization of the novel 3-dimensional hy-brid revealed high material's porosity with high specific surface area (402 m2 g-1) and homogeneous element distribution. The presence of multiple functional groups comprising sulphur, nitrogen and oxygen, provide additional contribution of Faradic redox reaction in supercapacity performance, leading to a high effective electrochemical pseudocapacitance...
December 5, 2018: Journal of the American Chemical Society
Haochen Si, Li Sun, Yu Zhang, Yuanxing Zhang, Liqi Bai, Yihe Zhang
A carbon-coated molybdenum dioxide-reduced graphene oxide (RGO@MoO2/C) composite was synthesized as a high-performance electrode for supercapacitors via a facile hydrothermal method. In this composite, RGO not only provided high conductivity to benefit effective electron transfer, but also offered nucleation sites to load in situ formed MoO2/C nanoparticles. The MoO2@C nanoparticles interconnected with each other forming nanoclusters and were anchored uniformly on RGO sheets instead of self-agglomerating into large aggregates...
December 5, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Luojiang Zhang, K N Hui, K S Hui, Siu Wing Or
High performance of an electrode relies largely on scrupulous design of nanoarchitectures and smart hybridization of bespoke active materials. Here, a 3D heterostructured core-shell architecture was fabricated as a supercapacitor electrode, in which Co3O4 nanowire cores were grown on nickel foam prior to the in situ deposition of layered double hydroxide (LDH) nanosheet shells. Owing to the unique configuration and hybridization, the as-fabricated Co3O4@LDH core-shell electrode exhibited high capacities of 818...
December 5, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Wu-Shuang Bai, Xin-Jin Zhang, Jian-Bin Zheng
Ordered PdCu and Co doped PdCu nanoparticles have been synthesized on graphene oxide (GO). The obtained Co-PdCu/GO composites were used to fabricate a H2O2 electrochemical sensor which exhibits an ultralow LOD (limit of detection) of 1.2 nM and an extra broad linear range of 5 nM-5.774 mM, and has been used to detect H2O2 in living cells successfully.
December 5, 2018: Analyst
Huan You, Zhaode Mu, Min Zhao, Jing Zhou, Yongjie Chen, Lijuan Bai
This work describes a voltammetric and ultrasensitive aptasensor for sulfadimethoxine (SDM). It is based on signal amplification by making use of a multifunctional fullerene-doped reduced graphene oxide nanohybrid. The nanohybrid was coated with poly(diallyldimethylammonium chloride) to obtain a material (P-C60 -rGO) with large specific surface area and a unique adsorption ability for loading it with glucose oxidase (GOx). The coating also facilitates the direct electron transfer between the active site of GOx and the glassy carbon electrode (GCE)...
December 4, 2018: Mikrochimica Acta
Yeong-Rae Son, Soo-Jin Park
In this study, a homogeneous and stable dispersion of graphene oxide (GO)/carbon nanotube (CNT) complexes (GCCs) was obtained by dispersing CNTs in an aqueous solution using GO in the absence of dispersing agents. Furthermore, carboxymethyl cellulose/GCC (CMC/GCC) nanocomposite films were prepared by a simple solution mixing-evaporation method. The dispersibility of the GCCs with different CNT contents was investigated by UV-Vis spectrophotometry. The morphological and crystalline structures of the samples were analyzed by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction...
December 4, 2018: Scientific Reports
Shaktivel Manavalan, Umamaheswari Rajaji, Shen-Ming Chen, Mani Govindasamy, S Steplin Paul Selvin, Tse-Wei Chen, M Ajmal Ali, Fahad M A Al-Hemaid, M S Elshikh
Herein, we report an efficient electrochemical sensor strategy for determination of epinephrine based on Bi2 O3 nanoparticle decorated reduced graphene oxide nanocomposite (Bi2 O3 @RGO). The Bi2 O3 @RGO was prepared by simple ultrasonic method and then it's morphological and crystal structure aspects were well characterized by physiological instruments. The electrode-electrolyte interfacial properties were examined to ensure the catalytic ability of composite sensing towards EP. The composite was deposited on the multi-conventional screen-printed electrode and was found to be desirable performance toward EP oxidation...
March 2019: Ultrasonics Sonochemistry
Baoyan Wu, Shihua Hou, Yongyong Xue, Zhan Chen
The study reports a facile and eco-friendly approach for nanomaterial synthesis and enzyme immobilization. A corresponding glucose biosensor was fabricated by immobilizing the gold nanoparticles (AuNPs) and glucose oxidase (GOD) multilayer films onto the polypyrrole (PPy)/reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) via the electrodeposition and self-assembly. PPy and graphene oxide were first coated on the surface of a bare GCE by the electrodeposition. Then, AuNPs and GOD were alternately immobilized onto PPy-RGO/GCE electrode using the electrodeposition of AuNPs and self-assembly of GOD to obtain AuNPs-GOD multilayer films...
December 1, 2018: Nanomaterials
Yao Huang, Yanyan Gong, Jingchun Tang, Siyu Xia
A novel thiol-functionalized graphene oxide/Fe-Mn (SGO/Fe-Mn) was investigated for aqueous Hg2+ and CH3 Hg+ removal. Mercury were removed mainly through ligand exchange and surface complexation with surface active sites (i.e., -SH, OH, OCO, CC, SiO, and ππ bond). SH had the strongest binding ability with mercury, forming sulfur-containing organic matter or polymers with Hg2+ , and sulfur-containing organometallic compounds or thiolate-like species with CH3 Hg+ . The BET sorption isotherm model well simulated the sorption isotherm data of Hg2+ (R2 =0...
November 18, 2018: Journal of Hazardous Materials
Yeongkyu Choi, Dasom Jeon, Yuri Choi, Dongseok Kim, Nayeong Kim, Minsu Gu, Sanghyun Bae, Taemin Lee, Hyun-Wook Lee, Byeong-Su Kim, Jungki Ryu
An efficient water oxidation photoanode based on hematite has been designed and fabricated by tailored assembly of graphene oxide (GO) nanosheets and cobalt polyoxometalates (Co-POM) water oxidation catalysts into a nacre-like multilayer architecture on a hematite photoanode. The deposition of catalytic multilayers provides a high photocatalytic efficiency and photoelectrochemical stability to underlying hematite photoanodes. Compared to the bare counterpart, the catalytic multilayer electrode exhibits a significantly higher photocurrent density and large cathodic shift in onset potential (~ 369 mV) even at neutral pH conditions due to the improved charge transport and catalytic efficiency from the rational and precise assembly of GO and Co-POM...
December 4, 2018: ACS Nano
Xiong Su, Xiao-Feng Yang, Yanqiang Huang, Bin Liu, Tao Zhang
Simply yet powerfully, single-atom catalysts (SACs) with atomically dispersed metal active centers on supports have received a growing interest in a wide range of catalytic reactions. As a specific example, SACs have exhibited distinctive performances in CO2 chemical conversions. The unique structures of SACs are appealing for adsorptive activation of CO2 molecules, transfer of intermediates from support to active metal sites, and production of desirable products in CO2 conversion. In this Account, we have exemplified our recent endeavors in the development of SACs toward CO2 conversions in thermal catalysis and electrocatalysis...
December 4, 2018: Accounts of Chemical Research
Xitong Liu, Chenxu Yan, Kai Loon Chen
The influence of solution chemistry on the adsorption of human serum albumin (HSA) proteins on graphene oxide (GO) was investigated through batch adsorption experiments and the use of a quartz crystal microbalance with dissipation (QCM-D). The conformation of HSA layers on GO was also examined with the QCM-D. Our results show that an increase in ionic strength under neutral pH conditions resulted in stronger binding between HSA and GO, as well as more compact HSA layers on GO, emphasizing the key role of electrostatic interactions in controlling HSA-GO interactions...
December 4, 2018: Environmental Science & Technology
Li Zhao, Jingting Kong, Natalia Krasteva, Dayong Wang
The developmental basis for the epidermal barrier against the translocation of nanomaterials is still largely unclear in organisms. We here investigated the effect of deficits in the epidermal barrier on the translocation and toxicity of PEG modified graphene oxide (GO-PEG) in Caenorhabditis elegans . In wild-type or NR222 nematodes, GO-PEG exposure did not cause toxicity and affect the expression of epidermal-development related genes. However, GO-PEG exposure resulted in toxicity in mlt-7(RNAi) nematodes with deficit in the function of epidermal barrier...
November 1, 2018: Toxicology Research
Hina Javed, Aminul Islam, Anjali Chauhan, Suneel Kumar, Sushil Kumar
Graphene oxide (GO) was immobilized innovatively through azo spacer arm onto the surface of polymeric Amberlite XAD-16 resin in order to expose all oxygen functionalities freely available for metal ions coordination and further modification with picolylamine which governs selectivity. The GO Amberlite XAD-16 picolylamine enables the development of SPE column coupled with ICP-OES for preconcentration and determination of Pb (II) and Cu (II) in water and fish samples. Elution was performed by mild acid (2M HCl) no other carcinogenic organic solvent was used, prevents ligand leaching...
December 3, 2018: Scientific Reports
Ke Fan, Haiyuan Zou, Yue Lu, Hong Chen, Fusheng Li, Jinxuan Liu, Licheng Sun, Lianpeng Tong, Michael F Toney, Manling Sui, Jiaguo Yu
As one of the most remarkable oxygen evolution reaction (OER) electrocatalysts, metal chalcogenides have been intensively reported due to their high OER activities during the past few decades. It has been reported that electron-chemical conversion of metal chalcogenides into oxides/hydroxides would take place after OER. However, the transition mechanism of such unstable structures, as well as the real active sites and catalytic activity during OER for these electrocatalysts, has not been understood yet, which urgently needs a direct observation for the electrocatalytic water oxidation process, especially at nano or even angstrom scale...
December 3, 2018: ACS Nano
Xiaolin Xing, Rongji Liu, Kecheng Cao, Ute Kaiser, Guangjin Zhang, Carsten Streb
The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are key catalytic processes for sustainable energy technologies such as water electrolysis or fuel cells. Here, a novel metal oxide - nanostructured carbon composite is reported which acts as OER and ORR electrocatalyst under technologically relevant conditions. A facile synthetic process allows the deposition of a molecular manganese vanadium oxide precursor, [Mn4V4O17(OAc)3]3-, on reduced graphene oxide. Simultaneously, the precursor is converted into insoluble nanostructured solid-state Mn-V-oxide catalysts...
December 3, 2018: ACS Applied Materials & Interfaces
Pei Lay Yap, Shervin Kabiri, Diana N H Tran, Dusan Losic
Engineering of multifunctional binding chemistry on graphene composites using thiol-ene click reaction for selective and highly efficient adsorption of mercury (II) is demonstrated. Graphene oxide (GO) is used as an initial material for covalent attachment of cysteamine molecules by thiol-ene click reaction on C=C groups to achieve a partially reduced graphene surface with multiple binding chemistry such as O, S, and N. Batch adsorption studies showed remarkable adsorption rate with only 1 mg L-1 dosage of adsorbent used to remove 95 % Hg (II) (~1...
December 3, 2018: ACS Applied Materials & Interfaces
Jianzhi Huang, Xinrong Guo, Guoqing Yue, Qiong Hu, Lishi Wang
Herein, we successfully synthesized partially oxidized 5 nm cobalt nanoparticles dispersed on single layer nitrogen-doped graphene (denoted as PO-5 nm Co/SL-NG) catalyst by a unique and simple one-pot synthesis strategy, which was efficient applied for highly selective electrocatalytic reduction of carbon dioxide to methanol in 0.1 mol dm-3 aqueous NaHCO3 medium under mild conditions, reaching the maximum faradic efficiency of 71.4% for methanol at -0.90 V versus SCE, possesses strong electrocatalytic current density of 4 mA cm-2 and high yield of 1...
December 3, 2018: ACS Applied Materials & Interfaces
Yan Chen, Xiuqiang Xie, Xin Xin, Zi-Rong Tang, Yi-Jun Xu
Assembly of two-dimensional (2D) layered structures into three-dimensional (3D) macroscopic hydrogel has been an enduring attracting research theme. However, the anisotropic intersheet cross-linking to form Ti3C2Tx MXene-based hydrogel remains intrinsically challenging because of the superior hydrophilic nature of 2D Ti3C2Tx. Herein, Ti3C2Tx MXene is ingeniously assembled into the 3D macroscopic hydrogel under mild conditions by a graphene oxide (GO) assisted self-convergence process. During the process, GO is reduced to reduced graphene oxide (RGO) by virtue of the reduction ability of Ti3C2Tx, leading to the partial removal of hydrophilic oxygen-containing groups and an increase of the hydrophobicity and the π-conjugated structures of RGO, which enables the assembly of RGO into 3D RGO framework...
December 3, 2018: ACS Nano
Kairi Yamato, Ryo Sekiya, Manabu Abe, Takeharu Haino
Excitation-dependent photoluminescence (PL) is well-known property of graphene quantum dots (GQDs). For the development of carbon-based photo-functional materials, GQDs possessing uniform PL properties are highly demanded. We established a protocol to separate spectroscopically uniform lipophilic GQD-1a from a GQD-1 mixture mainly composed of GQD-1a and GQD-1b. The GQD-1 mixture was synthesized by the reaction of p-methoxybenzyl amine with GQD-2 prepared from graphite by common oxidative exfoliations. Size exclusion chromatography gave raise to GQD-1a and GQD-1b with diameters of 19...
December 2, 2018: Chemistry, An Asian Journal
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