Journal of Nanomaterials http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Fabrication of Modified MMT/Glass/Vinylester Multiscale Composites and Their Mechanical Properties Thu, 03 Sep 2015 09:32:43 +0000 http://www.hindawi.com/journals/jnm/2015/506029/ Montmorillonite (MMT) may become a preferred filler material for fiber-reinforced polymer (FRP) composites due to its high aspect ratio, large surface area, and low charge density. In the present paper, MMT/glass/vinylester multiscale composites are prepared with untreated and surface-treated MMT clay particles with an MMT content of 1.0 wt%. Effects of surface treatment on mechanical properties of MMT/glass/vinylester multiscale composites are investigated through tensile and bending tests, which revealed enhanced mechanical properties in the case of surface-treated MMT. Thermal properties are studied through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). X-Ray diffraction is performed to investigate the interaction between MMT and the matrix. Fourier Transform Infrared (FTIR) is also performed for both untreated and surface-treated MMT. Furthermore, Field Emission-Scanning Electron Microscope (FE-SEM) is conducted to investigate the path of fracture propagation within the composite surface, showing that the surface-treated MMT based multiscale composite has better interactions with the host matrix than the untreated MMT multiscale composites. These composites with enhanced mechanical strength can be used for various mechanical applications. Garima Mittal, Vivek Dhand, Ji Il Ryu, Kyong Yop Rhee, Hyeon-Ju Kim, and Dong Ho Jung Copyright © 2015 Garima Mittal et al. All rights reserved. Cytotoxicity and Biological Efficacy of Exendin-4-Encapsulated Solid Lipid Nanoparticles in INS-1 Cells Thu, 03 Sep 2015 08:44:06 +0000 http://www.hindawi.com/journals/jnm/2015/753569/ Exendin-4 (Ex-4), a peptide of glucagon-like peptide-1 receptor agonist, is a potent insulinotropic agent and alternative drug delivery systems to increase therapeutic utility have been explored. We developed exendin-4-encapsulated solid lipid nanoparticles (Eudragit Ex-4 SLNs) and compared the effects of Eudragit Ex-4 SLNs with those of native Ex-4 on INS-1 cells. We observed no significant toxic effects of nanoparticles at concentrations from 1 nM to 100 nM. Similar to Ex-4, Eudragit Ex-4 SLNs stimulated the production of cyclic AMP at 10 nM. Moreover, unlike treatment with the vehicle, treatment with 10 nM Eudragit Ex-4 SLNs increased insulin mRNA levels and insulin secretion. These insulinotropic effects of Eudragit Ex-4 SLNs were comparable to those of Ex-4. Thus, our in vitro results suggest that the biological effects of Eudragit Ex-4 SLNs are similar to those of Ex-4, and further in vivo pharmacokinetic studies are required to propose an alternative sustained release drug system. Hee-Sook Jun, Gongdeuk Bae, Young Tag Ko, and Yoon Sin Oh Copyright © 2015 Hee-Sook Jun et al. All rights reserved. Microstructure Control of Columnar-Grained Silicon Substrate Solidified from Silicon Melts Using Gas Pressure Wed, 02 Sep 2015 12:32:54 +0000 http://www.hindawi.com/journals/jnm/2015/104930/ A silicon substrate with the dimensions of 100 × 140 × 0.3 mm was grown directly from liquid silicon with gas pressure. The silicon melt in the sealed melting part was injected into the growth part at applied pressure of 780–850 Torr. The solidified silicon substrate was then transferred by the pull of the cooled dummy bar. A desirable structure with a liquid-solid interface perpendicular to the pulling direction was formed when the mold temperature in the solidification zone of the growth part was much higher than that of the dummy bar, as this technique should be able to overcome thermal loss through the molds and the limited heat flux derived from the very narrow contact area between the silicon melt and the dummy bar. In addition, because the metallic impurities and expansion of volume during solidification are preferably moved to a liquid phase, a high-quality silicon substrate, without defects such as cracks and impurities in the substrate, could be manufactured in the interface structure. The present study reports the experimental findings on a new and direct growth system for obtaining silicon substrates characterized by high quality and productivity, as a candidate for alternate routes for the fabrication of silicon substrates. Jun-Kyu Lee, Sung-Min Wi, Jin-Seok Lee, Bo-Yun Jang, Joon-Soo Kim, Young-Soo Ahn, and Churl-Hee Cho Copyright © 2015 Jun-Kyu Lee et al. All rights reserved. Nanomaterials for Optical Sensing and Sensors: Plasmonics, Raman, and Optofluidics Wed, 02 Sep 2015 09:07:13 +0000 http://www.hindawi.com/journals/jnm/2015/162537/ Zhida Xu, Meng Lu, Hyunjong Jin, Tao Chen, and Tiziana C. Bond Copyright © 2015 Zhida Xu et al. All rights reserved. Investigating the Fabrication Imperfections of Plasmonic Nanohole Arrays and Its Effect on the Optical Transmission Spectra Wed, 02 Sep 2015 07:53:47 +0000 http://www.hindawi.com/journals/jnm/2015/178583/ We investigate the extraordinary optical transmission spectra of thin gold films perforated with imperfect nanohole arrays using the finite difference time domain (FDTD) method. Exponential shapes for the nanohole sidewalls are used. To the best of our knowledge, such investigation of transmission spectra of imperfect nanohole arrays has not previously been demonstrated. It was found that the asymmetry between the two openings of the circular nanoholes or bending to their sidewalls strongly modifies both the intensity and resonance positions of the transmission spectra. Furthermore, the results of this study assist in explaining the technicality of extraordinary optical transmission phenomenon and why some experimental results on transmission differ from those expected. Amr M. Mahros and Marwa M. Tharwat Copyright © 2015 Amr M. Mahros and Marwa M. Tharwat. All rights reserved. Molecular Logic Computation with Debugging Method Wed, 02 Sep 2015 07:51:47 +0000 http://www.hindawi.com/journals/jnm/2015/120365/ Seesaw gate concept, which is based on a reversible DNA strand branch process, has been found to have the potential to be used in the construction of various computing devices. In this study, we consider constructing full adder and serial binary adder, using the new concept of seesaw gate. Our simulation of the full adder preformed properly as designed; however unexpected exception is noted in the simulation of the serial binary adder. To identify and address the exception, we propose a new method for debugging the molecular circuit. The main idea for this method is to add fan-outs to monitor the circuit in a reverse stepwise manner. These fan-outs are fluorescent signals that can obtain the real-time concentration of the target molecule. By analyzing the monitoring result, the exception can be identified and located. In this paper, examples of XOR and serial binary adder circuits are described to prove the practicability and validity of the molecular circuit debugging method. Xiangrong Liu, Juan Suo, Juan Liu, Yan Gao, and Xiangxiang Zeng Copyright © 2015 Xiangrong Liu et al. All rights reserved. FRET-Based Detection of Enzymatic Reaction of Botulinum on Microfluidic Device Tue, 01 Sep 2015 08:54:48 +0000 http://www.hindawi.com/journals/jnm/2015/126598/ A microfluidic device was implemented to detect the enzymatic reaction of botulinum toxin A (BTA) using Förster resonance energy transfer (FRET). The microfluidic device comprised a main channel having two loading zones, a reaction chamber and a side channel perpendicular to the main channel. The reaction chamber defined by weir in the main channel was packed with microbeads. The movement of the peptide substrate and the BTA in the microfluidic device was controlled by electrophoresis, and the enzymatic reaction of the BTA was detected through the changes of the fluorescence intensity in the reaction chamber. As a result, it was observed that the enzymatic reaction was affected by the electric voltage applied for the movement of the BTA and the peptide and improved by packing the microbeads in the reaction chamber. The microfluidic device provides the tool to investigate the proteolysis of the substrate by the BTA. Young Min Bae, Seung Oh Jin, Insoo Kim, and Ki Young Shin Copyright © 2015 Young Min Bae et al. All rights reserved. Investigation of the Validity of the Universal Scaling Law on Linear Chains of Silver Nanoparticles Tue, 01 Sep 2015 08:47:39 +0000 http://www.hindawi.com/journals/jnm/2015/983413/ Due to the wide range of variation in the plasmonic characteristics of the metallic nanoparticles arranged in linear arrays, the optical spectra of these arrays provide a powerful platform for spectroscopic studies and biosensing applications. Due to the coupling effect between the interacting nanoparticles, the excited resonance mode is shifted with the interparticle separation. The change in the resonance energy of the coupled mode is expressed by the fractional plasmon shift which would normally follow a universal scaling behavior. Such a universal law has been successfully applied on a system of dimers under parallel polarization. It has been found that the plasmon shift decays exponentially over interparticle spacing. The decay length is independent of both the nanoparticle and dielectric properties of the surrounding medium. In this paper, the discrete dipole approximation (DDA) is used to examine the validity of extending the universal scaling law to linear chains of several interacting nanoparticles embedded in various host media for both parallel and perpendicular polarizations. Our calculations reveal that the decay length of both the coupled longitudinal mode (LM) and transverse modes (TM) is strongly dependent on the refractive index of the surrounding medium . The decay constant of the LM is linearly proportional to while the corresponding constant of the TM decays exponentially with . Upon changing the nanoparticle size, the change in the peak position of the LM decreases exponentially with the interparticle separation and hence, it obeys the universal law. The sensitivity of coupled LM to the nanoparticle size is more pronounced at both smaller nanoparticle sizes and separations. The sensitivity of the coupled TM to the nanoparticle size on the other hand changes linearly with the separation and therefore, the universal law does not apply in the case of the excited TM. Mohammed Alsawafta, Mamoun Wahbeh, and Vo-Van Truong Copyright © 2015 Mohammed Alsawafta et al. All rights reserved. Immobilization Techniques and Integrated Signal Enhancement for POC Nanocolor Microfluidic Devices Tue, 01 Sep 2015 08:36:12 +0000 http://www.hindawi.com/journals/jnm/2015/386794/ Resonance enhanced absorption (REA) nanocolor microfluidic devices are new promising bioassay platforms, which employ nanoparticle- (NP-) protein conjugates for the immunodetection of medically relevant markers in biologic samples such as blood, urine, and saliva. The core component of a REA test device is a PET chip coated with aluminum and SiO2 thin layers, onto which biorecognitive molecules are immobilized. Upon addition of a sample containing the analyte of interest, a NP-protein-analyte complex is formed in the test device that is captured on the REA chip, for example, via streptavidin-biotin interaction. Thereby, a colored symbol is generated, which allows optical readout. Silver enhancement of the bound nanoparticles may be used to increase the sensitivity of the assay. Herein, we demonstrate that adsorptive immobilization via a cationic polymeric interlayer is a competitive and fast technique for the binding of the capture protein streptavidin onto planar SiO2 surfaces such as REA biochips. Moreover, we report the development of a silver enhancement technology that operates even in the presence of high chloride concentrations as may be encountered in biologic samples. The silver enhancement reagents may be integrated into the microfluidic assay platform to be released upon sample addition. Hereby, a highly sensitive one-step assay can be realized. Marlies Schlauf, Saied Assadollahi, Roland Palkovits, Peter Pointl, and Thomas Gerhard Maria Schalkhammer Copyright © 2015 Marlies Schlauf et al. All rights reserved. Focused Ion Beam Assisted Interface Detection for Fabricating Functional Plasmonic Nanostructures Tue, 01 Sep 2015 08:26:51 +0000 http://www.hindawi.com/journals/jnm/2015/468069/ Plasmonic nanoscale devices/structures have gained more attention from researchers due to their promising functions and/or applications. One important technical focus on this rapidly growing optical device technology is how to precisely control and fabricate nanostructures for different functions or applications (i.e., patterning end points should locate at/near the interface while fabricating these plasmonic nanostructures), which needs a systematic methodology for nanoscale machining, patterning, and fabrication when using the versatile nanoprecision tool focused ion beam (FIB), that is, the FIB-assisted interface detection for fabricating functional plasmonic nanostructures. Accordingly, in this work, the FIB-assisted interface detection was proposed and then successfully carried out using the sample-absorbed current as the detection signal, and the real-time patterning depth control for plasmonic structure fabrication was achieved via controlling machining time. Besides, quantitative models for the sample-absorbed currents and the ion beam current were also established. In addition, some nanostructures for localized surface plasmon resonance biosensing applications were developed based on the proposed interface detection methodology for FIB nanofabrication of functional plasmonic nanostructures. It was shown that the achieved methodology can be conveniently used for real-time control and precise fabrication of different functional plasmonic nanostructures with different geometries and dimensions. Houxiao Wang, Wei Zhou, and Er Ping Li Copyright © 2015 Houxiao Wang et al. All rights reserved. Synthesis and Characterization of an Amphiphilic Linoleic Acid-g-Quaternary Chitosan with Low Toxicity Mon, 31 Aug 2015 13:27:58 +0000 http://www.hindawi.com/journals/jnm/2015/568925/ A novel amphiphilic derivative of chitosan, namely, a linoleic acid-g-quaternary chitosan (LA-g-QC), was designed and synthesized as low toxic material for biomedical applications in this study. The chemical structure of LA-g-QC was characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (1H-NMR), and elemental analysis. LA-g-QC could form nanosized micelles with self-assembly, which was confirmed by the results of critical micelle concentration (CMC) via fluorescence spectroscopy. The average size of LA-g-QC was 140 nm and its zeta potential was approximately +35.50 mV. CMC value was 31.00 mg/mL. Furthermore, LA-g-QC micelles, at final concentrations between 0.94 μg/mL and 30 μg/mL, did not inhibit the proliferation of HepG2 or SMMC 7721 cell lines. Taken together, LA-g-QC has low cytotoxicity and high potential for the preparation of novel drug-delivery micelles. Xiaobin Fang, Yingqi Xu, Jinming Zhang, Xianghong Lu, Yitao Wang, and Meiwan Chen Copyright © 2015 Xiaobin Fang et al. All rights reserved. Ultra-Small Fatty Acid-Stabilized Magnetite Nanocolloids Synthesized by In Situ Hydrolytic Precipitation Sun, 30 Aug 2015 14:30:53 +0000 http://www.hindawi.com/journals/jnm/2015/620672/ Simple, fast, large-scale, and cost-effective preparation of uniform controlled magnetic nanoparticles remains a major hurdle on the way towards magnetically targeted applications at realistic technical conditions. Herein, we present a unique one-pot approach that relies on simple basic hydrolytic in situ coprecipitation of inexpensive metal salts (Fe2+ and Fe3+) compartmentalized by stabilizing fatty acids and aided by the presence of alkylamines. The synthesis was performed at relatively low temperatures (~80°C) without the use of high-boiling point solvents and elevated temperatures. This method allowed for the production of ultra-small, colloidal, and hydrophobically stabilized magnetite metal oxide nanoparticles readily dispersed in organic solvents. The results reveal that the obtained magnetite nanoparticles exhibit narrow size distributions, good monodispersities, high saturation magnetizations, and excellent colloidal stabilities. When the [fatty acid] : [Fe] ratio was varied, control over nanoparticle diameters within the range of 2–10 nm was achieved. The amount of fatty acid and alkylamine used during the reaction proved critical in governing morphology, dispersity, uniformity, and colloidal stability. Upon exchange with water-soluble polymers, the ultra-small sized particles become biologically relevant, with great promise for theranostic applications as imaging and magnetically targeted delivery vehicles. Kheireddine El-Boubbou, Rabih O. Al-Kaysi, Muhanna K. Al-Muhanna, Hassan M. Bahhari, Abdulaziz I. Al-Romaeh, Nadim Darwish, Khaled O. Al-Saad, and Salem D. Al-Suwaidan Copyright © 2015 Kheireddine El-Boubbou et al. All rights reserved. Room Temperature Imprint Using Crack-Free Monolithic SiO2-PVA Nanocomposite for Fabricating Microhole Array on Silica Glass Sun, 30 Aug 2015 13:32:54 +0000 http://www.hindawi.com/journals/jnm/2015/584320/ This paper aims to fabricate microhole arrays onto a silica glass via a room temperature imprint and subsequent sintering by using a monolithic SiO2-poly(vinyl alcohol) (PVA) nanocomposite as the silica glass precursor. The SiO2-PVA suspension was prepared from fumed silica particles and PVA, followed by drying to obtain tailored SiO2-PVA nanocomposites. The dependence of particle size of the fumed silica particles on pore size of the nanocomposite was examined. Nanocomposites prepared from 7 nm silica particles possessed suitable mesopores, whereas the corresponding nanocomposites prepared from 30 nm silica particles hardly possessed mesopores. The pore size of the nanocomposites increased as a function of decreasing pH of the SiO2-PVA suspension. As a consequence, the crack-free monolithic SiO2-PVA nanocomposite was obtained using 7 nm silica particles via the suspension at pH 3. Micropatterns were imprinted on the monolithic SiO2-PVA nanocomposite at room temperature. The imprinted nanocomposite was sintered to a transparent silica glass at 1200°C in air. The fabricated sintered glass possessed the microhole array on their surface with aspect ratios identical to the mold. Shigeru Fujino and Hiroshi Ikeda Copyright © 2015 Shigeru Fujino and Hiroshi Ikeda. All rights reserved. Quantum Dots and Nanoparticles in Light Emitting Diodes, Displays, and Optoelectronic Devices Sun, 30 Aug 2015 08:32:04 +0000 http://www.hindawi.com/journals/jnm/2015/371679/ Hsueh-Shih Chen, Ping Yang, Zishan H. Khan, Jyh Ming Wu, Guoran Li, and Ali Reza Kamali Copyright © 2015 Hsueh-Shih Chen et al. All rights reserved. Gold Nanoparticles Size Design and Control by Poly(N,N′-diethylaminoethyl methacrylate) Sun, 30 Aug 2015 08:25:39 +0000 http://www.hindawi.com/journals/jnm/2015/273814/ Poly(N,N′-diethylaminoethyl methacrylate) (PDEAEM) with different molecular weights was used to stabilize gold nanoparticles (AuNPs) obtained by in situ reduction of tetrachloroauric acid using citrates under acidic conditions and in organic/alcoholic medium. The influence of the pH value on gold nanoparticle size in the presence of PDEAEM was investigated. Results show that the pH of the reacting mixture has a dramatic effect on the size, polydispersity, and morphology of the resulting AuNPs. Moreover, the size of the nanoparticles (NPs) may be modified by changing the solution’s pH or by changing the solvent type. Electron microscope images showed that the sizes of AuNPs coated with PDEAEM were not sensitive to the variation of the polymer molecular weight in the range between 9000 and 29300 g/mol; however their aggregation behavior depended strongly on the polymer molecular weight as revealed by dynamic light scattering studies. AuNPs stabilized with PDEAEM (AuNP@PDEAEM) are stable in water at acidic pH and in organic polar solvents. Norma A. Cortez-Lemus, Angel Licea-Claverie, Francisco Paraguay-Delgado, and Gabriel Alonso-Nuñez Copyright © 2015 Norma A. Cortez-Lemus et al. All rights reserved. Catalytic Hydrodechlorination of Trichlorobenzenes with Pd(Phen)Cl2 as Catalyst Precursor Thu, 27 Aug 2015 15:48:58 +0000 http://www.hindawi.com/journals/jnm/2015/912104/ We reported the catalytic hydrodechlorination (HDC) of trichlorobenzenes by an organometallic compound Pd(Phen)Cl2 as a catalyst precursor. The catalyst precursor was prepared by chemical coordination reaction and characterized by FTIR and 1H NMR techniques. The HDC performance of Pd(Phen)Cl2 as catalyst precursor was evaluated on 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes (TCBs). All TCBs could be converted to dechlorination products with high conversion. Products distribution was closely related with the substrate structures and C-Cl bond energies. A reasonable reaction mechanism was also proposed. Guanlin Zhang, Hu Xu, Yuehui Fan, Yuhong Wang, Lirong Zhang, and Guanzhong Lu Copyright © 2015 Guanlin Zhang et al. All rights reserved. Evolution of InAs/GaAs QDs Size with the Growth Rate: A Numerical Investigation Thu, 27 Aug 2015 15:19:45 +0000 http://www.hindawi.com/journals/jnm/2015/847018/ This paper investigates the impact of the deposition rate on the mean buried InAs/GaAs quantum dots’ (QDs) size by means of a coupled photoluminescence spectroscopy and numerical approach. The proposed method consists in tuning the theoretical transition energies by changing the QDs aspect ratio towards best fit of the photoluminescence emission energies arising from the state filling effect. The electron-hole confined states are obtained by solving the single particle one band effective mass Schrödinger equation in cylindrical coordinates for a lens shaped QD by finite element method taking into account the strain effects. The obtained evolution is in agreement with morphological data taken from similar uncapped QDs samples. Bouraoui Ilahi, Manel Souaf, Mourad Baira, Jawaher Alrashdi, Larbi Sfaxi, Abdulaziz Alhazaa, and Hassen Maaref Copyright © 2015 Bouraoui Ilahi et al. All rights reserved. Improvement in Tracing Quantum Dot-Conjugated Nanospheres for In Vivo Imaging by Eliminating Food Autofluorescence Thu, 27 Aug 2015 13:39:42 +0000 http://www.hindawi.com/journals/jnm/2015/894353/ Fluorescence imaging using fluorescent probes has demonstrated long-term stability and brightness suitable for in vivo deep-tissue imaging, but it also allows intense background fluorescence associated with food in the near-infrared (IR) range. We investigated effects of changing rodent diet on food autofluorescence, in the presence of quantum dots-conjugated magnetic nanospheres (QD-MNSs). Replacement of a regular rodent diet with a purified diet has great improvement in removing autofluorescence in the near-infrared range ideal for in vivo fluorescence imaging. By feeding a purified diet for eliminating ingredients impairing desirable fluorescence signals in the near-IR range, food autofluorescence was clearly eliminated and fluorescence probes, QD-MNSs, introduced by i.v. injection were effectively traced in a mouse by a distinctive signal-to-noise ratio. Chul-Kyu Park and Hoonsung Cho Copyright © 2015 Chul-Kyu Park and Hoonsung Cho. All rights reserved. High Luminescence White LEDs Prepared with 2D Island-Pattern of Quantum Dots Dispersed Photopolymer Films Thu, 27 Aug 2015 12:26:38 +0000 http://www.hindawi.com/journals/jnm/2015/828067/ Since the reabsorption loss among different size quantum dots (QDs) is a critical issue in the QD based white LEDs, we proposed and fabricated new film structure of 2D island-patterns consisting of separate green and red QDs dispersed photopolymer patterns in a zigzag form. A small air-gap such as 60 μm between QD islands helps to control the optical path at the interface to reduce the lateral reabsorption loss to enhance the optical efficiency of white LED. The 2D island-patterns of QD phosphor film were fabricated using a UV imprinting process and compared the optical efficiency with the other QD film structure prepared with same QD concentrations and thicknesses such as a mixed and separately layered QD structure. Experimental and simulation analysis were performed to confirm the better optical efficiency from the 2D island-patterns of QD films due to the reduced reabsorption loss. High luminescence white LED was finally realized with 2D island-patterns of QD film, resulting in a luminous efficiency of 62.2 lm/W and CRI of 83 with CCT of 4537 K at the operation current of 60 mA. Hyun-Guk Hong, Min-Ho Shin, Hyo-Jun Kim, Jinsoo Shin, and Young-Joo Kim Copyright © 2015 Hyun-Guk Hong et al. All rights reserved. Synthesis of High Crystalline Al-Doped ZnO Nanopowders from Al2O3 and ZnO by Radio-Frequency Thermal Plasma Thu, 27 Aug 2015 12:17:59 +0000 http://www.hindawi.com/journals/jnm/2015/151532/ High crystalline Al-doped ZnO (AZO) nanopowders were prepared by in-flight treatment of ZnO and Al2O3 in Radio-Frequency (RF) thermal plasma. Micron-sized (~1 μm) ZnO and Al2O3 powders were mixed at Al/Zn ratios of 3.3 and 6.7 at.% and then injected into the RF thermal plasma torch along the centerline at a feeding rate of 6.6 g/min. The RF thermal plasma torch system was operated at the plate power level of ~140 kVA to evaporate the mixture oxides and the resultant vapor species were condensed into solid particles by the high flow rate of quenching gas (~7000 slpm). The FE-SEM images of the as-treated powders showed that the multipod shaped and the whisker type nanoparticles were mainly synthesized. In addition, these nanocrystalline structures were confirmed as the single phase AZO nanopowders with the hexagonal wurtzite ZnO structure by the XRD patterns and FE-TEM results with the SAED image. However, the composition changes of 0.3 and 1.0 at.% were checked for the as-synthesized AZO nanopowders at Al/Zn ratios of 3.3 and 6.7 at.%, respectively, by the XRF data, which can require the adjustment of Al/Zn in the mixture precursors for the applications of high Al doping concentrations. Min-Kyeong Song, Mi-Yeon Lee, Jun-Ho Seo, Min-Ho Kim, and Shi-Young Yang Copyright © 2015 Min-Kyeong Song et al. All rights reserved. Direct Determination of Spatial Localization of Carriers in CdSe-CdS Quantum Dots Thu, 27 Aug 2015 12:09:20 +0000 http://www.hindawi.com/journals/jnm/2015/321354/ Colloidal quantum dots (QDs) have gained significant attention due to their tunable band gap, simple solution processability, ease of scale-up, and low cost. By carefully choosing the materials, core-shell heterostructure QDs (HQDs) can be further synthesized with a controlled spatial spread of wave functions of the excited electrons and holes for various applications. Many investigations have been done to understand the exciton dynamics by optical characterizations. However, these spectroscopic data demonstrate that the spatial separation of the excitons cannot distinguish the distribution of excited electrons and holes. In this work, we report a simple and direct method to determine the localized holes and delocalized electrons in HQDs. The quasi-type-II CdSe-CdS core-shell QDs were synthesized via a thermolysis method. Poly(3-hexylthiophene) (P3HT) nanofiber and ZnO nanorods were selected as hole and electron conductor materials, respectively, and were combined with HQDs to form two different nanocomposites. Photoelectrical properties were evaluated under different environments via a quick and facile characterization method, confirming that the electrons in the HQDs were freely accessible at the surface of the nanocrystal, while the holes were confined within the CdSe core. Yichen Zhao, Abhilash Sugunan, Qin Wang, Xuran Yang, David B. Rihtnesberg, and Muhammet S. Toprak Copyright © 2015 Yichen Zhao et al. All rights reserved. Core-Shell Structure of Gold Nanoparticles with Inositol Hexaphosphate Nanohybrids for Label-Free and Rapid Detection by SERS Nanotechnology Thu, 27 Aug 2015 11:49:50 +0000 http://www.hindawi.com/journals/jnm/2015/857154/ Gold nanoparticles bound with inositol hexaphosphate (IP6) (AuNPs/IP6) were prepared by in situ reduction of various concentrations of IP6 (0~320 µM) through modified Frens method for surface-enhanced Raman scattering (SERS) detection. The resultant AuNPs/IP6 were subject to characterization including UV/Vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, and X-ray photoelectron spectroscopy (XPS). The results showed that AuNPs with 65 µM of IP6 would result in a core AuNPs-shell (IP6 layer) structure, which exhibited the strongest SERS signal, due to the “hot spot effect” generated from the 1-2 nm interparticle gaps of AuNPs/IP6 nanohybrids (ionic interaction of IP6 and Au+). Furthermore, the reaction kinetics of Au and IP6 were also investigated in this work. Higher concentration of IP6 (190 and 260 µM) will make AuNPs become irregularly shaped, because IP6 is a basic salt and served as a pH mediator. The morphology and distribution of AuNPs were greatly improved by addition of 65 µM of IP6. This novel AuNPs/IP6 nanohybrid showed great stability and Raman enhancement. It is promising in the application of rapid and label-free biological detection of bacteria or tumor cells. Andreas H. H. Mevold, Jin-Yuan Liu, Li-Ying Huang, Hung-Liang Liao, Ming-Chien Yang, Tzu-Yi Chan, Kuan-Syun Wang, Juen-Kai Wang, Yuh-Lin Wang, and Ting-Yu Liu Copyright © 2015 Andreas H. H. Mevold et al. All rights reserved. The Core/Shell Structure of CdSe/ZnS Quantum Dots Characterized by X-Ray Absorption Fine Spectroscopy Thu, 27 Aug 2015 11:43:45 +0000 http://www.hindawi.com/journals/jnm/2015/764712/ Understanding the chemical and physical properties of core/shell nanocrystal quantum dots (QDs) is key for their use in light-emission applications. In this paper, a single-step injection-free scalable synthetic method is applied to prepare high-quality core/shell QDs with emission wavelengths of 544 nm, 601 nm, and 634 nm. X-ray absorption fine structure spectra are used to determine the core/shell structure of CdSe/ZnS quantum dots. Moreover, theoretical XANES spectra calculated by FEFF.8.20 are used to determine the structure of Se and S compounds. The QD samples displayed nearly spherical shapes with diameters of approximately 3.4 ± 0.5 nm (634 nm), 4.5 ± 0.4 nm (601 nm), and 5.5 ± 0.5 nm (544 nm). With XANES results and MS calculations, it is indicated that sphalerite ZnS capped with organic sulfur ligands should be the shell structure. Wurtzite CdSe is the main core structure with a Cd-Se bond length of 2.3 Å without phase shift. This means that different emission wavelengths are only due to the crystal size with single-step injection-free synthesis. Therefore, single-step injection-free synthesis could generate a nearly ideal core/shell structure of CdSe/ZnS QDs capped with an organic sulfur ligand. Huijing Wei, Jing Zhou, Linjuan Zhang, Fang Wang, Jianqiang Wang, and Chan Jin Copyright © 2015 Huijing Wei et al. All rights reserved. Catalyst Nanomaterials Thu, 27 Aug 2015 08:27:33 +0000 http://www.hindawi.com/journals/jnm/2015/514309/ Ping Xu, Bo Song, Hongmei Luo, Ling Fei, and Hsing-Lin Wang Copyright © 2015 Ping Xu et al. All rights reserved. Preparation of Mesoporous Silica-Supported Chiral Amino Alcohols for the Enantioselective Addition of Diethylzinc to Aldehyde and Asymmetric Transfer Hydrogenation to Ketones Wed, 26 Aug 2015 12:02:42 +0000 http://www.hindawi.com/journals/jnm/2015/381836/ Optically active (−)-ephedrine, (−)-norephedrine, and (−)-prolinol were immobilized onto cubic mesoporous MCM-48 silica. The immobilized amino alcohols served as a heterogeneous chiral catalyst for the asymmetric addition of diethylzinc to aldehydes and transfer hydrogenation to ketones. The developed catalytic process yielded optically enriches secondary aromatic alcohols with 92–99% conversion and 70–82% enantioselectivity. Shaheen M. Sarkar, Md. Eaqub Ali, Md. Lutfor Rahman, and Mashitah Mohd Yusoff Copyright © 2015 Shaheen M. Sarkar et al. All rights reserved. Silver Nanoparticles Influence on Photocatalytic Activity of Hybrid Materials Based on TiO2 P25 Wed, 26 Aug 2015 11:45:26 +0000 http://www.hindawi.com/journals/jnm/2015/210734/ The aim of the present study consists in the obtaining of a hybrid material film, obtained using TiO2 P25 and silver nanoparticles (AgNPs). The film manufacturing process involved realization of physical mixtures of TiO2 P25 and AgNPs dispersions. The size distribution of the AgNPs proved to be a key factor determining the photodegradation activity of the materials measured using methyl orange. The best result was 33% degradation of methyl orange (MO) after 150 min. The second approach was the generation of AgNPs on the surface of TiO2 P25. The obtained hybrid material presents photocatalytic activity of 45% MO degradation after 150 min. The developed materials were characterized by UV-VIS, SEM, and DLS analyses. Tomkouani Kodom, Edina Rusen, Ioan Călinescu, Alexandra Mocanu, Raluca Şomoghi, Adrian Dinescu, Aurel Diacon, and Cristian Boscornea Copyright © 2015 Tomkouani Kodom et al. All rights reserved. Direct Synthesis of Porous Multilayer Graphene Materials Using Thermal Plasma at Low Pressure Wed, 26 Aug 2015 07:02:40 +0000 http://www.hindawi.com/journals/jnm/2015/724508/ Porous multilayer graphenes have been synthesized by decomposition of hydrocarbons in a thermal plasma jet. Products of synthesis were characterized by electron microscopy, thermogravimetry, Raman spectroscopy, and X-ray diffraction. Possibility of producing a wide range of graphene materials with different morphology and structure has been shown. Influence of the experimental conditions on mesopores structure of the synthesis products has been investigated using the method of “limited evaporation.” Ravil Amirov, Marina Shavelkina, Nariman Alihanov, Evgeny Shkolnikov, Alexander Tyuftyaev, and Natalya Vorob’eva Copyright © 2015 Ravil Amirov et al. All rights reserved. A Platinum Monolayer Core-Shell Catalyst with a Ternary Alloy Nanoparticle Core and Enhanced Stability for the Oxygen Reduction Reaction Tue, 25 Aug 2015 14:20:00 +0000 http://www.hindawi.com/journals/jnm/2015/715474/ We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core. The core-shell Pd1Ir1Ni2@Pt/C catalyst exhibits excellent oxygen reduction reaction activity, yielding a mass activity significantly higher than that of Pt monolayer catalysts containing PdIr or PdNi nanoparticles as cores and four times higher than that of a commercial Pt/C electrocatalyst. In 0.1 M HClO4, the half-wave potential reaches 0.91 V, about 30 mV higher than that of Pt/C. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst. We suggest that the porous structure resulting from the dissolution of Ni in the alloy nanoparticles may be the main reason for the catalyst’s enhanced performance. Haoxiong Nan, Xinlong Tian, Lijun Yang, Ting Shu, Huiyu Song, and Shijun Liao Copyright © 2015 Haoxiong Nan et al. All rights reserved. Synthesis of Hydrocarbons from H2-Deficient Syngas in Fischer-Tropsch Synthesis over Co-Based Catalyst Coupled with Fe-Based Catalyst as Water-Gas Shift Reaction Tue, 25 Aug 2015 14:17:52 +0000 http://www.hindawi.com/journals/jnm/2015/268121/ The effects of metal species in an Fe-based catalyst on structural properties were investigated through the synthesis of Fe-based catalysts containing various metal species such, as Mn, Zr, and Ce. The addition of the metal species to the Fe-based catalyst resulted in high dispersions of the Fe species and high surface areas due to the formation of mesoporous voids about 2–4 nm surrounded by the catalyst particles. The metal-added Fe-based catalysts were employed together with Co-loaded beta zeolite for the synthesis of hydrocarbons from syngas with a lower H2/CO ratio of 1 than the stoichiometric H2/CO ratio of 2 for the Fischer-Tropsch synthesis (FTS). Among the catalysts, the Mn-added Fe-based catalyst exhibited a high activity for the water-gas shift (WGS) reaction with a comparative durability, leading to the enhancement of the CO hydrogenation in the FTS in comparison with Co-loaded beta zeolite alone. Furthermore, the loading of Pd on the Mn-added Fe-based catalyst enhanced the catalytic durability due to the hydrogenation of carbonaceous species by the hydrogen activated over Pd. Ting Ma, Hiroyuki Imai, Tomohiro Shige, Taisuke Sugio, and Xiaohong Li Copyright © 2015 Ting Ma et al. All rights reserved. Fe3+-Exchanged Titanate Nanotubes: A New Kind of Highly Active Heterogeneous Catalyst for Friedel-Crafts Type Benzylation Tue, 25 Aug 2015 13:26:40 +0000 http://www.hindawi.com/journals/jnm/2015/738089/ Heterogeneous catalysis for Friedel-Crafts type benzylation has received much attention in recent years due to its characteristic of environmental benefits. In this paper, titanate nanotubes (TNTs) were employed as heterogeneous catalyst support, and a new kind of Fe3+-exchanged titanate nanotubes (Fe-TNTs) catalyst with highly dispersed ferric sites was constructed by an ion exchange technique. The obtained catalyst was systematically characterized by XRD, TEM, N2 adsorption, XPS, and UV-vis spectra. As expected, Fe-TNTs showed excellent catalytic activities in the benzylation of benzene and benzene derivatives. The recycling tests for Fe-TNTs were also carried out, where the reason for the gradually decreased activity was carefully investigated. Superior to some reported catalysts, the catalytic ability of used Fe-TNTs could be easily recovered by ion exchange again, indicating that Fe-TNTs herein were a highly active and durable heterogeneous catalyst for Friedel-Crafts type benzylation. These results might be helpful for the design and preparation of novel heterogeneous catalysts by combining the structural advantages of titanate nanotubes and active metal ions. Yunchen Du, Di Guo, Meiling Xiong, Yanwu Qi, Chenkui Cui, Jun Ma, Xijiang Han, and Ping Xu Copyright © 2015 Yunchen Du et al. All rights reserved.