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Qiang Hao, Xiuxiu Niu, Changshun Nie, Simeng Hao, Wei Zou, Jiangman Ge, Daimei Chen, Wenqing Yao
SiO2, an insulator, hardly has any photocatalytic acitivity due to its intrinsic property, and it is generally used as a hard template to increase the surface area of catalysts. However, in this work, we found that the surface state of the insulator SiO2 can promote the migration of photogenerated charge carriers, leading to the enhancement of the photooxidation ability of graphitic carbon nitride (g-C3N4). A one-pot calcination method was employed to prepare g-C3N4/SiO2 composites using melamine and SiO2 as precursors...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Tingsheng Zhou, Yao Zhou, Ruguang Ma, Zhenzhen Zhou, Guanghui Liu, Qian Liu, Yufang Zhu, Jiacheng Wang
In situ formation of nitrogen-doped carbon nanoparticles on hollow carbon spheres (NHCSs) were successfully realised via a simple, scalable emulsion polymerization route using melamine as the nitrogen precursor, followed by thermal treatment at 1000 °C in N2. All NHCSs show large BET specific surface areas (648.2-837.7 cm(2) g(-1)) and pore volumes (0.91-1.16 cm(3) g(-1)), evidently superior to N-free hollow carbon spheres (HCSs) (524.3 cm(2) g(-1) and 0.48 cm(3) g(-1), respectively). This unique nanocomposite has hierarchical micro-/mesoporosity (1...
October 14, 2016: Nanoscale
Chang Yu, Zhiqiang Liu, Xiangtong Meng, Bing Lu, Dan Cui, Jieshan Qiu
Alternative high-performance electrocatalysts for triiodide (I3(-)) reduction of low-cost dye-sensitized solar cells (DSSCs) are urgently sought after. To address the concerned issues, we report a facile strategy for engineering the nitrogen and phosphorus dual-doped graphene (NPG) via an efficient ball-milling process, followed by a simple thermal annealing approach utilizing melamine (C3H6N6) and triphenylphosphine ((C6H5)3P) as the N and P source, respectively. When employed as the counter electrode (CE) in DSSCs, such a metal-free material exhibits excellent electrocatalytic activity towards the I3(-)/I(-) redox reaction...
October 14, 2016: Nanoscale
Pill Won Seo, Nazmul Abedin Khan, Zubair Hasan, Sung Hwa Jhung
A highly porous metal-organic framework (MOF), MIL-101, was modified to introduce urea or melamine via grafting on open metal sites of the MOF. Adsorptive removal of three artificial sweeteners (ASWs) was studied using the MOFs, with or without modifications (including nitration), and activated carbon (AC). The adsorbed quantities (based on the weight of the adsorbent) of saccharin (SAC) under various conditions decreased in the order urea-MIL-101 > melamine-MIL-101 > MIL-101 > AC > O2N-MIL-101; however, the quantities based on unit surface area are in the order melamine-MIL-101 > urea-MIL-101 > MIL-101 > O2N-MIL-101...
October 10, 2016: ACS Applied Materials & Interfaces
Tingting Wang, Junfeng Ma, Yihui Chen, Ying Li, Lihua Zhang, Yukui Zhang
Analysis of melamine and its analogues is of increasing research interest recently. Owing to their high nitrogen content and low price, they were deliberately added to artificially enhance protein concentration in a number of different types of human and animal food sources. In addition, environmental water might also be contaminated by melamine due to its use in the chemical industry and the degradation of the pesticide cyromazine. Herein we provide a detailed overview of recently developed materials and techniques for the analysis of melamine and its analogues in complex matrices, especially in dairy products (e...
October 10, 2016: Journal of Separation Science
Miriam Kaltenbach, Stephane Emond, Florian Hollfelder, Nobuhiko Tokuriki
The extent to which an emerging new function trades off with the original function is a key characteristic of the dynamics of enzyme evolution. Various cases of laboratory evolution have unveiled a characteristic trend; a large increase in a new, promiscuous activity is often accompanied by only a mild reduction of the native, original activity. A model that associates weak trade-offs with "evolvability" was put forward, which proposed that enzymes possess mutational robustness in the native activity and plasticity in promiscuous activities...
October 2016: PLoS Genetics
Zonghua Pu, Ibrahim Saana Amiinu, Xiaobo Liu, Min Wang, Shichun Mu
There is a crucial demand for cost-effective hydrogen evolution reaction (HER) catalysts towards future renewable energy systems, and the development of such catalysts operating under all pH conditions still remains a challenging task. In this work, a one-step facile approach to synthesizing nitrogen-doped carbon encapsulating molybdenum phosphide nanoparticles (MoP NPs@NC) is introduced by using ammonium molybdate, ammonium dihydrogen phosphate and melamine as precursor. Benefitting from structural advantages, including ultrasmall nanoparticles, large exposed surface area and fast charge transfer, MoP NPs@NC exhibits excellent HER catalytic activities with small overpotentials at all pH values (j = 10 mA cm(-2) at η = 115, 136 and 80 mV in 0...
October 6, 2016: Nanoscale
Chengchao Chu, Shengxiang Ge, Jing Zhang, Huirong Lin, Gang Liu, Xiaoyuan Chen
We present a simple colorimetric assay for EV71 virus detection based on the aggregation of 4-mercaptobenzoic acid (4-MBA) and melamine (MA) modified silver nanoparticles (4-MBA-MA-AgNPs) in the presence of Mn(2+). The EV71-Ab1 was incubated on a 96-well plate and the EV71-Ab2 was labeled on the surface of three-dimensional nanoflower-like MnO2-PEG (3D-MnO2-PEG). After layer-by-layer immunoreactions, the EV71 virus and the corresponding 3D-MnO2-PEG-Ab2 were captured on the plate. With the addition of Vitamin C (Vc), Mn(2+) was released from the 3D-MnO2-PEG and then the aggregation of the 4-MBA-MA-AgNPs was induced, allowing a naked-eye detection limit of EV71 virus to be as low as 5 × 10(4) particles per mL, which is about three orders of magnitude lower than the conventional enzyme-linked immunosorbent assay (ELISA)...
September 15, 2016: Nanoscale
Yufei Guo, Jing Li, Yupeng Yuan, Lu Li, Mingyi Zhang, Chenyan Zhou, Zhiqun Lin
Highly crystalline graphitic carbon nitride (g-C3 N4 ) with decreased structural imperfections benefits from the suppression of electron-hole recombination, which enhances its hydrogen generation activity. However, producing such g-C3 N4 materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high-quality g-C3 N4 with reduced structural defects by judiciously combining the implementation of melamine-cyanuric acid (MCA) supramolecular aggregates and microwave-assisted thermolysis...
October 6, 2016: Angewandte Chemie
He Feng, Lei Wang, Lu Zhao, Chungui Tian, Peng Yu, Honggang Fu
The exploration of low-cost and highly efficient non-platinum electrocatalysts for the oxygen reduction reaction (ORR) is vital for renewable systems. Herein, we report a novel non-platinum electrocatalyst consisting of B and N separately co-doped graphitic carbon encapsulated Fe/Fe3C nanoparticles (BNGFe), which were synthesized from a facile method by adopting melamine, iron nitrate and boric acid as the precursors. In this synthesis, the N atoms in melamine first bond with the iron ions in iron nitrate, which could prevent the formation of BN covalent bonds during the subsequent pyrolysed process, resulting in the formation of effective B and N separately co-doped graphitic carbon encapsulated on the Fe/Fe3C nanoparticles...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Lei Liu, Shi-Da Xu, Qing Yu, Feng-Yun Wang, Hui-Ling Zhu, Ru-Liang Zhang, Xin Liu
Nitrogen-doped hollow carbon spheres with a wrinkled surface were rationally synthesized for the first time by using graphene oxide as a morphology controlling agent through direct pyrolysis of core-shell structured GO-resol@melamine formaldehyde composites, showing excellent rate performance towards supercapacitors, due to their unique structural and surface properties.
September 22, 2016: Chemical Communications: Chem Comm
Jian Guo Wen, Xin Jian Liu, Zhi Min Wang, Tian Fang Li, Mark L Wahlqvist
The melamine contaminated milk powder contamination scandal occurred in China in 2008. Its main consequences so far have been urinary stone formation in children with associated renal damage and increased child mortality. Eight years have passed, but food safety issues still remain of concern in the daily lives of millions of Chinese. Vigilance is required to ensure no recurrence of such food safety problems. Ongoing studies focus on the early detection of food industry malpractice, mechanisms whereby these toxic substances induce disease and how its advent may be prevented and better managed...
December 2016: Asia Pacific Journal of Clinical Nutrition
Hanbing Rao, Min Chen, Hongwei Ge, Zhiwei Lu, Xin Liu, Ping Zou, Xianxiang Wang, Hua He, Xianyin Zeng, Yanying Wang
A novel molecularly imprinted electrochemical sensor for the rapid detection of melamine was reported in this paper. Glassy carbon electrode (GCE) was modified by Au and polyaniline composites (Au@PANI) deposited on the surface of GCE and were used to increase the electrode sensitivity and to amplify the sensor signal. Melamine template molecule was further assembled onto Au@PANI by the formation of hydrogen bonds, can implement the selective detection of melamine. This simple but efficient electrochemistry analysis platform presents a low detection limit of 1...
September 22, 2016: Biosensors & Bioelectronics
Wenlong Cai, Jianbin Zhou, Gaoran Li, Kailong Zhang, Xianyu Liu, Can Wang, Heng Zhou, Yongchun Zhu, Yitai Qian
B, N-co-doped graphene supported sulfur (S@BNG) composite is synthesized by using melamine diborate as precursor. XPS spectra illustrates that BNG with a high percentage and dispersive B, N (B: 13.47 %, N: 9.17 %) and abundant pyridinic-N and N-B/N=B bond, which show strong interaction with Li2Sx proved by simulation experiments. As cathode for Li-S half cell, S@BNG with a sulfur content of 75 % displays a high capacity of 765 mA h g-1 at 1 C even after 500 cycles with a low fading rate of 0.027 % per cycle...
October 3, 2016: ACS Applied Materials & Interfaces
Caili Fu, Chang Liu, Ying Li, Yajing Guo, Fang Luo, Peilong Wang, Longhua Guo, Bin Qiu, Zhenyu Lin
Abasic site (AP site) in the triplex structure can recognize specific target with high selectivity. In this study, this character was first applied to develop a simple, sensitive, and selective homogeneous electrochemical biosensor for melamine determination. The assay combines the advantage of the high selectivity of the DNA triplex structure containing an AP site to melamine and high efficiency of exonuclease (Exo) III-assisted recycling amplification. DNA-1 (T1), DNA-2 (T2), poly[dA] probe containing an AP site (8A) and methylene blue-labeled DNA probe (dMB probe) were carefully designed...
October 3, 2016: Analytical Chemistry
S A Rounaghi, H Eshghi, S Scudino, A Vyalikh, D E P Vanpoucke, W Gruner, S Oswald, A R Kiani Rashid, M Samadi Khoshkhoo, U Scheler, J Eckert
Hexagonal Aluminium nitride (h-AlN) is an important wide-bandgap semiconductor material which is conventionally fabricated by high temperature carbothermal reduction of alumina under toxic ammonia atmosphere. Here we report a simple, low cost and potentially scalable mechanochemical procedure for the green synthesis of nanostructured h-AlN from a powder mixture of Aluminium and melamine precursors. A combination of experimental and theoretical techniques has been employed to provide comprehensive mechanistic insights on the reactivity of melamine, solid state metal-organic interactions and the structural transformation of Al to h-AlN under non-equilibrium ball milling conditions...
2016: Scientific Reports
Lina Li, Yubao Zhao, Markus Antonietti, Menny Shalom
The assembly of melamine and 2,5-dihydroxy-1,4-benzoquinone results in new "sheet-like" supramolecular crystals that by controlled thermal condensation can be converted to photoactive materials at relativity low temperatures. The condensation temperature alters the materials properties from polymer-like to carbon materials alongside their morphology and elemental ratio. This new method opens the possibility for the synthesis of new organic, photoactive carbon-nitrogen based frameworks at low calcination temperatures with great simplicity...
September 20, 2016: Small
Michele Fiore, Peter Strazewski
There may be more than one way leading to RNA: Recent discoveries in the synthesis of nucleoside and nucleotide precursors are described and put into the wider context of prebiotic systems chemistry. Mixing Butlerow's carbohydrate precursors with Traube's 5-formylaminopyrimidines has led to the formation of prebiotic purine nucleosides whereas the mixing of 5-phosphoribose with barbituric acid and melamine gave supramolecular fibers from stacks of Whitesides' rosettas.
September 15, 2016: Angewandte Chemie
Yibao Li, Wei Liu, Linxiu Cheng, Ping Huang, Yu Peng, Yongquan Wu, Xun Li, Xiaokang Li, Xiaolin Fan
In this study, we report a novel three-component luminescent hydrogel, which is composed of amino acid derivatives (N,N'-di valine-3,4,9,10-perylenetetracarboxylic acid, NVPD), riboflavin (RF), and melamine (MM). The three-component hydrogel is attributed to multiple hydrogen bonds and the strong π-π stacking interaction between these molecules. Based on the strong hydrogen bonding of the gelator, when the reversible process between the gel and the solution take places it changes the pH of the system from 6...
September 12, 2016: Journal of Functional Biomaterials
Ye Sun, Yaqiang Duan, Liang Hao, Zipeng Xing, Ying Dai, Rui Li, Jinlong Zou
The low electrocatalytic activity for oxygen reduction reaction (ORR) and the high cost of cathode catalyst in microbial fuel cells (MFCs) are the important factors that limit the practical applications. The metal-free nitrogen (N)-doped partly graphitized carbon (NPGC) as cathode catalyst is prepared at different temperatures (700-1050 °C) by using waste cornstalks as the carbon source and melamine as the N source. Scanning electron microscopy, X-ray diffraction, specific surface areas, and transmission electron microscopy have been used, in parallel with electrochemical activity tests including rotating disk electrode (RDE) and power output, to clarify how the active constituents and structure of NPGC influence the MFCs performance...
October 5, 2016: ACS Applied Materials & Interfaces
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