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https://www.readbyqxmd.com/read/28931284/one-step-synthesis-of-fluorescent-boron-nitride-quantum-dots-via-a-hydrothermal-strategy-using-melamine-as-nitrogen-source-for-the-detection-of-ferric-ions
#1
Bingbing Huo, Bingping Liu, Tao Chen, Liang Cui, Gengfang Xu, Mengli Liu, Jingquan Liu
A facile and effective approach for the preparation of functionalized born nitride quantum dots (BNQDs) with blue fluorescence was explored by the hydrothermal treatment of the mixture of boric acid and melamine at 200 oC for 15 h. The as-prepared BNQDs were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and fluorescence spectroscopy. The single layered BNQDs with the average size of 3 nm showed a blue light emission under the illumination of the UV light...
September 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28926984/n-doped-carbon-xerogels-as-pt-support-for-the-electro-reduction-of-oxygen
#2
Cinthia Alegre, David Sebastián, María E Gálvez, Estela Baquedano, Rafael Moliner, Antonino S Aricò, Vincenzo Baglio, María J Lázaro
Durability and limited catalytic activity are key impediments to the commercialization of polymer electrolyte fuel cells. Carbon materials employed as catalyst support can be doped with different heteroatoms, like nitrogen, to improve both catalytic activity and durability. Carbon xerogels are nanoporous carbons that can be easily synthesized in order to obtain N-doped materials. In the present work, we introduced melamine as a carbon xerogel precursor together with resorcinol for an effective in-situ N doping (3-4 wt % N)...
September 17, 2017: Materials
https://www.readbyqxmd.com/read/28917784/green-synthesis-of-graphitic-carbon-nitride-nanosheet-g-c3n4-and-using-it-as-a-label-free-fluorosensor-for-detection-of-metronidazole-via-quenching-of-the-fluorescence
#3
Amir Hatamie, Farzanh Marahel, Ali Sharifat
In this research, g-C3N4nanosheets were facilely fabricated by thermal polymerization and then exfoliated into ultrathin nanosheets through ultrasonication in water media. Low-cost C-N nanosheets prepared by melamine possessed a highly π-conjugated structure and fluorescence property. In the present study, the g-C3N4nanosheet was used as a switch-off fluorescence sensor for rapid and sensitive sensing of metronidazole in biological fluids. These nanosheets were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28914524/templated-and-catalytic-fabrication-of-n-doped-hierarchical-porous-carbon-carbon-nanotubes-hybrids-as-host-for-lithium-sulfur-batteries
#4
Junjie Cai, Chun Wu, Shaoran Yang, Ying Zhu, Pei Kang Shen, Kaili Zhang
Nitrogen-doped hierarchical porous carbon and carbon nanotube hybrids (N-HPC-CNTs) are fabricated by simple pyrolysis of the N-rich raw material melamine-formaldehyde (MF) resin in the presence of nano-CaCO3 and bimetallic combination of Fe-Co catalyst. During carbonization, nano-CaCO3 acts as template for creating a hierarchical porous carbon and the N atoms originated from MF resin are in-situ doped into the carbon matrix simultaneously. Meanwhile, volatile gases generated by the thermal decomposition of MF resin could serve as carbon and nitrogen sources to grow nitrogen doped CNTs on HPC...
September 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28912505/biomimetic-silica-nanoparticles-prepared-by-a-combination-of-solid-phase-imprinting-and-ostwald-ripening
#5
Elena Piletska, Heersh Yawer, Francesco Canfarotta, Ewa Moczko, Katarzyna Smolinska-Kempisty, Stanislav S Piletsky, Antonio Guerreiro, Michael J Whitcombe, Sergey A Piletsky
Herein we describe the preparation of molecularly imprinted silica nanoparticles by Ostwald ripening in the presence of molecular templates immobilised on glass beads (the solid-phase). To achieve this, a seed material (12 nm diameter silica nanoparticles) was incubated in phosphate buffer in the presence of the solid-phase. Phosphate ions act as a catalyst in the ripening process which is driven by differences in surface energy between particles of different size, leading to the preferential growth of larger particles...
September 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28901369/precisely-tunable-thickness-of-graphitic-carbon-nitride-nanosheets-for-visible-light-driven-photocatalytic-hydrogen-evolution
#6
Yuanzhi Hong, Changsheng Li, Di Li, Zhenyuan Fang, Bifu Luo, Xu Yan, Hongqiang Shen, Baodong Mao, Weidong Shi
Graphitic carbon nitride (GCN) nanosheets with unique physicochemical properties have received increasing attention in the area of photocatalysis, yet tunable thickness for the straightforward production of this graphite-like two-dimensional (2D) nanomaterial remains a challenge. In this work, GCN nanosheets with different thicknesses were firstly prepared by a direct calcination of melamine supramolecular aggregates (MSA) obtained from a hydrochloric acid (HCl)-induced hydrothermal assembly approach. The resultant nanosheets over nanometer scale thickness could be precisely controlled via simply adjusting the HCl concentration...
September 13, 2017: Nanoscale
https://www.readbyqxmd.com/read/28895434/genetic-variation-and-risk-of-dna-damage-in-peripheral-blood-lymphocytes-of-iranian-formaldehyde-exposed-workers
#7
Rezvan Zendehdel, Parviz Abdolmaleki, Fatemeh Javani Jouni, Mohammad Mazinani
Formaldehyde (FA) has given positive results for the genetic damage evaluated in human peripheral blood lymphocytes. Polymorphism plays a special role in the toxicity of chemicals. DNA damage in blood cells was evaluated in workers who were occupationally exposed to FA. This study tested the association of alcohol dehydrogenase III (ADH3) and manganese-superoxide dismutase (Mn-SOD) gene polymorphism, with DNA damage of peripheral blood lymphocytes. Gene polymorphisms were evaluated in 54 workers from melamine dinnerware workshops and 34 workers from dairy production workshops...
January 1, 2017: Human & Experimental Toxicology
https://www.readbyqxmd.com/read/28895281/encapsulated-vanadium-based-hybrids-in-amorphous-n-doped-carbon-matrix-as-anode-materials-for-lithium-ion-batteries
#8
Bei Long, Muhammad-Sadeeq Balogun, Lei Luo, Yang Luo, Weitao Qiu, Shuqin Song, Lei Zhang, Yexiang Tong
Recently, researchers have made significant advancement in employing transition metal compound hybrids as anode material for lithium-ion batteries and developing simple preparation of these hybrids. To this end, this study reports a facile and scalable method for fabricating a vanadium oxide-nitride composite encapsulated in amorphous carbon matrix by simply mixing ammonium metavanadate and melamine as anode materials for lithium-ion batteries. By tuning the annealing temperature of the mixture, different hybrids of vanadium oxide-nitride compounds are synthesized...
September 12, 2017: Small
https://www.readbyqxmd.com/read/28884596/3d-map-modelling-for-the-melting-points-prediction-of-intumescent-flame-retardant-coatings
#9
A S Korotkov, M Gravit
The applicability of 3D map modelling for melting point prediction was studied. The melting points in the ammonium polyphosphate-pentaerythritol-melamine chemical system of intumescent flame-retardant coatings over a wide range of concentrations were collected. The ternary diagram (triangle) of the melting points was plotted and an approximated 3D map was built for the range 205-345°C. The present work contains the thermal data for the observed ternary system and provides a new graphic system for making predictions for intumescent flame-retardant coatings...
September 8, 2017: SAR and QSAR in Environmental Research
https://www.readbyqxmd.com/read/28881199/nitrogen-doped-carbon-nanotubes-based-on-melamine-formaldehyde-resin-as-highly-efficient-catalyst-for-oxygen-reduction-reaction
#10
Xin Zhang, Ying Huang, Xuefang Chen, Qiao Gao, Weichao Zhang
The preparation of highly efficient and cheap electrocatalysts toward oxygen reduction reaction is significant for many electrochemical cells. Here we facilely synthesized nitrogen doped carbon nanotube by pyrolyzing melamine formaldehyde resin and Fe loading on MgO. There were mainly three morphologies observed, slender bamboo-like CNT, thick bamboo-like CNT, surface smooth, hollow CNT. The content of Fe loading on MgO had little influence on morphologies of CNT, however, when no MgO as support, only carbon ribbon obtained...
September 1, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28878158/optimizing-melamine-resin-microspheres-with-excess-formaldehyde-for-the-sers-substrate
#11
Lu Shen, Junfu Zhu, Yuqing Guo, Zhirong Zhu, Xiaogang Wang, Zhixian Hao
Influence of the excess monomer within the synthetic reaction solution of melamine resin microspheres (MFMSs) on the surface-enhanced Raman spectroscopy (SERS) enhancement from Rhodamine 6G (R6G) was investigated, where the R6G was adsorbed on the silver nanoparticles (AgNPs) that were loaded on the MFMSs. Surface characteristics of the MFMSs were modified by the excess monomer (i.e., the excessive melamine or formaldehyde) through its terminal overreaction, which can be simply controlled by some of the synthetic reaction conditions, thus further allowing us to optimize the assembly of the loaded AgNPs for the SERS detection...
September 6, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28846901/synthesis-of-cobalt-impregnated-carbon-composite-derived-from-a-renewable-resource-characterization-and-catalytic-performance-evaluation
#12
Dong-Wan Cho, Kwang-Hwa Jeong, Sohyun Kim, Daniel C W Tsang, Yong Sik Ok, Hocheol Song
A novel nitrogen-doped biochar embedded with cobalt (Co-NB) was fabricated via pyrolysis of glucose pretreated with melamine (N donor) and Co(II). The Co-NB showed high catalytic capability by converting p-nitrophenol (PNP) into p-aminophenol (PAP) by NaBH4. The analyses of FE-SEM, TEM, BET, XRD, Raman, and X-ray photoelectron spectroscopy XPS of the Co-NB showed hierarchical porous structure (BET 326.5m(2)g(-1) and pore volume: 0.2403cm(3)g(-1)) with well-dispersed Co nanoparticles (20-60nm) on the N-doped graphitic biochar surface...
August 25, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28838291/zero-valent-iron-supported-on-nitrogen-doped-carbon-xerogel-as-catalysts-for-the-oxidation-of-phenol-by-fenton-like-system
#13
S A Messele, O S G P Soares, J J M Órfão, C Bengoa, J Font
Nitrogen-free and nitrogen-doped carbon xerogel materials, from urea and melamine precursors, were prepared at different pH and evaluated as adsorbents/catalysts in the removal of phenol. Then ZVI was supported on these carbon xerogel materials and its activity was again evaluated for phenol removal by adsorption and catalytic wet peroxide oxidation (CWPO). The prepared samples were characterized by N2 adsorption at -196 °C, pH at the point of zero charge (pHPZC) and elemental analysis. The textural properties of the N-free and N-doped carbon xerogels are strongly influenced by the pH of the preparation solution and precursor used...
August 25, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28837328/direct-detection-of-dilute-solid-chemicals-with-responsive-lateral-organic-diodes
#14
Jia Huang, Guoqian Zhang, Xingang Zhao, Xiaohan Wu, Dapeng Liu, Yingli Chu, Howard E Katz
Organic field-effect transistors (OFETs) have emerged as promising sensors targeting chemical analytes in vapors and liquids. However, the direct detection of solid chemicals by OFETs has not been achieved. Here for the first time, we describe the direct detection of solid chemical analytes by organic electronics. An organic diode structure based on a horizontal side-by-side p-n junction was adopted and shown to be superior to OFETs for this purpose. The diodes showed more than 40% current decrease upon exposure to 1 ppm melamine powders...
August 29, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28827619/self-sacrificed-template-synthesis-of-ribbon-like-hexagonal-boron-nitride-nano-architectures-and-their-improvement-on-mechanical-and-thermal-properties-of-pha-polymer
#15
Yan Zhao, Zhenya Liu, Chaochao Cao, Chong Wang, Yi Fang, Yang Huang, Chao Yu, Jun Zhang, Lanlan Li, Long Hu, Chengchun Tang
Two-dimensional (2-D) boron nitride (BN) nanomaterials have received intensive attention because of their attractive mechanical, thermal and chemical stability. Here we demonstrate, for the first time, the synthesis of ribbon-like hexagonal boron nitride nano-architectures (RLBN) through a simple self-sacrificed template method using the cheap boric acid and melamine as raw materials. After the freeze-drying and thermal decomposition process, uniform ultrathin RLBN with width of 200-500 nm and thick of a few nanometers can be obtained...
August 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28802526/sodium-hyaluronate-functionalized-urea-formaldehyde-monolithic-column-for-hydrophilic-in-tube-solid-phase-microextraction-of-melamine
#16
Jiabin Wang, Nan Jiang, Zhengmiao Cai, Wenbang Li, Jianhua Li, Xucong Lin, Zenghong Xie, Lijun You, Qiqing Zhang
A novel sodium hyaluronate-functionalized urea-formaldehyde (UF) monolithic column has been developed by in-situ polycondensation of urea, formaldehyde and sodium hyaluronate (HA). HA plays both the roles of crosslinking and hydrophilic functionalization. The preparation factors including different molecular weights of HA and different amounts of HA were optimized, and then a uniform monolith with satisfactory permeability and hydrophilic binding capacity was obtained. Due to the excellent hydrophilicity of HA, HA-functionalized UF monolith showed higher hydrophilic extraction efficiency than UF monolith, and was applied for hydrophilic in-tube solid-phase microextraction (SPME) of melamine (MEL)...
August 3, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28798334/nitrogen-doped-carbon-paper-with-3d-porous-structure-as-a-flexible-free-standing-anode-for-lithium-ion-batteries
#17
Hua Zhang, Juntan Yang, Haoqing Hou, Shuiliang Chen, Haimin Yao
In this paper, a novel nitrogen-doped carbon paper (NCP) with both highly dense three-dimensional cellular structure and excellent bending flexibility is fabricated by pyrolyzing a melamine foam under compression. When serving as a free-standing anode for lithium-ion batteries, the NCP electrode delivers a reversible capacity up to 329.8 mA h g(-1) after 200 cycles at 0.5 A g(-1) (1.34 C) and 126.5 mA h g(-1) after 500 cycles at 8.0 A g(-1) (21.5 C). Such electrochemical performance is much higher than those of the counterparts prepared by pyrolysis without compression and can be mainly attributed to (a) the 3D highly dense interconnected carbon network with numerous junctions which can facilitate the efficient electron transfer and provide short transportation paths for lithium ions; and (b) the excellent mechanical flexibility and self-standing capability which exempt the use of binder, conductive additive and current collector...
August 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28795574/molecularly-imprinted-porous-monolithic-materials-from-melamine-formaldehyde-for-selective-trapping-of-phosphopeptides
#18
Mingquan Liu, Tri Minh Tran, Ahmed Awad Abbas Elhaj, Silje Bøen Torsetnes, Ole N Jensen, Börje Sellergren, Knut Irgum
Thirty-five melamine-formaldehyde (MF) monolithic materials with bimodal pore distributions were synthesized in fused silica capillaries by catalyst-free polycondensation, starting with an aqueous MF precondensate, using acetonitrile as the macroporogen and a variety of aliphatic polyethers and triblock copolymeric surfactants as porogens and mesoporogens, respectively. By varying the prepolymer composition and the type and molecular weight of the polymeric porogen components, a library of porous monolithic materials was produced, covering a range of meso- and macroporous properties...
September 5, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28792432/a-unique-3d-nitrogen-doped-carbon-composite-as-high-performance-oxygen-reduction-catalyst
#19
Ramesh Karunagaran, Tran Thanh Tung, Cameron Shearer, Diana Tran, Campbell Coghlan, Christian Doonan, Dusan Losic
The synthesis and properties of an oxygen reduction catalyst based on a unique 3-dimensional (3D) nitrogen doped (N-doped) carbon composite are described. The composite material is synthesised via a two-step hydrothermal and pyrolysis method using bio-source low-cost materials of galactose and melamine. Firstly, the use of iron salts and galactose to hydrothermally produceiron oxide (Fe₂O₃) magnetic nanoparticle clusters embedded carbon spheres. Secondly, magnetic nanoparticles diffused out of the carbon sphere when pyrolysed in the presence of melamine as nitrogen precursor...
August 9, 2017: Materials
https://www.readbyqxmd.com/read/28782775/sequential-nested-assembly-at-the-liquid-solid-interface
#20
Baharan Karamzadeh, Thomas Eaton, David Muñoz Torres, Izabela Cebula, Marcel Mayor, Manfred Buck
Studying the stepwise assembly of a four component hybrid structure on Au(111)/mica, the pores of a hydrogen bonded bimolecular network of 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) and 1,3,5-triazine-2,4,6-triamine (melamine) were partitioned by three and four-armed molecules based on oligo([biphenyl]-4-ylethynyl)benzene, followed by the templated adsorption of either C60 fullerene or adamantane thiol molecules. The characterisation by ambient scanning tunneling microscopy (STM) reveals that the pore modifiers exhibit dynamics which pronouncedly depend on the molecular structure...
August 7, 2017: Faraday Discussions
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