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2011

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Physical Chemistry

Articles 1 - 22 of 22

Full-Text Articles in Nanoscience and Nanotechnology

Preparation And Application Of Nano-Nio As Anode In Lithium-Ion Batteries, Cheng-Dong Bai, Jia-Jia Chen, Qi Zhang, Ming-Sen Zheng, Quan-Feng Dong Nov 2011

Preparation And Application Of Nano-Nio As Anode In Lithium-Ion Batteries, Cheng-Dong Bai, Jia-Jia Chen, Qi Zhang, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

In this work, the nano-NiO material was prepared by hydrothermal method. The surface morphologies and electrochemical properties of nano-NiO material were investigated. The special nano-NiO material with porous surface assembling honeycombs(100-200nm) was obtained by using surface active agents. The discharge capacity of nano-NiO electrode up to 2385.7 mAh/g was achieved at current density of 0.1A/g in the first circle,while 1100mAh/g could be maintained after 100 circles. At current density of 2.0A/g, the discharge capacity of 600 mAh/g was obtained. And when the current density was reduced to 0.1A/g, the discharge capacity was restored to 1050 mAh/g. The nano-NiO electrode exhibited …

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Superhydrophilic/Superhydrophobic Surface Constructions On Titanium And Their Effects On Anti-Bacterial Properties, Guo-Wei Wang, Qiao-Ling Huang, Ren Hu, Chang-Jian Lin, Hao Wang, Li-Hai Zhang, Pei-Fu Tang Nov 2011

Superhydrophilic/Superhydrophobic Surface Constructions On Titanium And Their Effects On Anti-Bacterial Properties, Guo-Wei Wang, Qiao-Ling Huang, Ren Hu, Chang-Jian Lin, Hao Wang, Li-Hai Zhang, Pei-Fu Tang

Journal of Electrochemistry

The microbial infection of biomaterials often causes clinic problems and sometimes even leads to the prosthesis failure. It is, therefore, important to prevent the biomaterials from bacterial contamination. This can be done by using anti-bacteria drugs. However, this method causes physiological burdens to the patients and does not always work. To stop the contamination from the just beginning is believed to be a better choice. The first step for infection is the attachment of bacteria on the material. In this work, the thin TiO2 nanotubes array films were constructed with totally different wettabilities showing either superhydrophobic or superhydrophilic. The bacterial …

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Electrocatalytic Determination Of 15 Kinds Of Phenolic Compounds By Novel Gold Nanoparticles-Modified Glassy Carbon Electrode, Yan-Ping Cui, Wei-Xing Wang, Chang-Zhu Yang, Wen-Hong Pu Nov 2011

Electrocatalytic Determination Of 15 Kinds Of Phenolic Compounds By Novel Gold Nanoparticles-Modified Glassy Carbon Electrode, Yan-Ping Cui, Wei-Xing Wang, Chang-Zhu Yang, Wen-Hong Pu

Journal of Electrochemistry

A gold nanoparticles modified glassy carbon electrode (Au/GCE) was used to detect 15 kinds of phenolic compounds. In the cyclic voltammetry measurements, the peak currents of phenolic compounds at Au/GCE were all increased as compared with GCE and planar gold electrodes, and the oxidation potentials were determined by the activity of analytes. Besides, electrocatalysis of salicylic acid was studied at Au/GCE. The results showed that, there was a good linear relationship between the oxidation current and the concentration of salicylic acid, and the current sensitivity was 1.8 fold higher than that obtained on GCE. Trace phenolic compounds determination could be …

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Electrochemical Studies On Surface Inclusion Of Β-Cyclodextrin With Adriamycin, Jian Shi, Qi-Ping Zhang, Nan-Ping Wang Nov 2011

Electrochemical Studies On Surface Inclusion Of Β-Cyclodextrin With Adriamycin, Jian Shi, Qi-Ping Zhang, Nan-Ping Wang

Journal of Electrochemistry

The β-cyclodextrin (β-CD) modified gold electrode (β-CD/Au) was fabricated to study the electrochemical behavior of adriamycin (ADM). The results indicated that the complexing reaction of ADM with β-CD took place at the β-CD/Au surface. At 25 ℃，the complexing constant (K) was 9.54×104 L?mol-1 in pH=7.0. The K values changed regularly with temperature, and the most suitable temperature of the surface inclusion reaction was 30 ℃. The complexing reaction of ADM with β-CD at the β-CD/Au surface could undergo the quasi-reversible electrochemical reaction with the rate constant being 0.0995 s-1. The cathodic peak current (Ip) of ADM was proportional to the …

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Development Of Dehydrogenase-Based Bioanode Using Poly(Phenosafranin)-Functionalized Swcnt Nanocomposites And Its Application To Ethanol Biosensor, S. Saleh Farhana, Okajima Takeyoshi, Mao Lanqun, Takeo Ohsaka Aug 2011

Development Of Dehydrogenase-Based Bioanode Using Poly(Phenosafranin)-Functionalized Swcnt Nanocomposites And Its Application To Ethanol Biosensor, S. Saleh Farhana, Okajima Takeyoshi, Mao Lanqun, Takeo Ohsaka

Journal of Electrochemistry

A New type of dehydrogenase-based amperometric ethanol biosensor was constructed using alcohol dehydrogenase (ADH) which was immobilized on the edge-plane pyrolytic graphite (EPPG) electrode modified with poly(phenosafranin)-functionalized single-walled carbon nanotube (PPS-SWCNT). The PPS-SWCNT modified EPPG electrode was prepared by electropolymerization of phenosafranin on the EPPG electrode which was previously coated with SWCNT. The performance of the ADH/PPS-SWCNT/EPPG electrode was evaluated using cyclic voltammetry and amperometry in the presence of ethanol. The fabricated ethanol biosensor provided a reasonable sensitivity of 2.0 μA cm–2 mM–1 and a low detection limit (36 μM) for the electrocatalytic oxidation of ethanol with a linear concentration …

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Study On The Fluorescent Carbon Nanodots With Electrochemical Methods, Bao-Ping Qi, Yan-Min Long, Lei Bao, Cui Liu, Zhi-Ling Zhang, Dai-Wen Pang Aug 2011

Study On The Fluorescent Carbon Nanodots With Electrochemical Methods, Bao-Ping Qi, Yan-Min Long, Lei Bao, Cui Liu, Zhi-Ling Zhang, Dai-Wen Pang

Journal of Electrochemistry

Carbon nanodots are a new class of fluorescent nanoparticles with a carbon-based core, which possess wavelength-tunable luminescence, high photostability, resistance to photobleaching, water-solubility, and ease of bioconjugation. Owing to their attractive merits, carbon nanodots like other carbon nanomaterials such as fullerene, carbon nanotubes and graphene, have attracted much attention. In addition, carbon nanodots can be inexpensively produced by electrochemical methods with simple post-processing under mild conditions. Electrochemical approaches have unique advantages in the analysis of surface structures and luminescence mechanism of materials. In this review, recent advances in electrochemical methods used for the synthesis and luminescence mechanism of fluorescent carbon …

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Study On The Electrochemical Behaviors Of Gc Electrode Modified With Carbon Nanotube-Polyelectrolytes And Its Application For Rutin Detection, Liang Hua, Xia-Qin Wu, Rong Wang Aug 2011

Study On The Electrochemical Behaviors Of Gc Electrode Modified With Carbon Nanotube-Polyelectrolytes And Its Application For Rutin Detection, Liang Hua, Xia-Qin Wu, Rong Wang

Journal of Electrochemistry

The electrochemical behaviors of rutin and ascorbic acid at single-wall carbon nanotube and polyelectrolytes (dimethyl-diallylammonium chloride, PDDA) film modified glassy carbon electrode was investigated. The cyclic voltammetric results showed that electron transfer of rutin at PDDA/SWCNTs/GC modified electrode is an adsorption-controlled process. The separation of oxidation peak potentials of rutin and ascorbic acid was more than 200 mV. The rutin concentration in the presence of AA were detected by differential pulse voltammetry (DPV). The experimental results indicated that the PDDA/SWCNTs/GC modified electrode can be used for the detection of rutin in the presence of high concentration of AA. The DPV …

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Surface Diffusion Of Adsorptive Species On Gold Nanoelectrodes, Bao-Fa Su, Wei Wang, Dong-Ping Zhan, Bin Ren, Zhong-Qun Tian Aug 2011

Surface Diffusion Of Adsorptive Species On Gold Nanoelectrodes, Bao-Fa Su, Wei Wang, Dong-Ping Zhan, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Gold nanoelectrodes were prepared successfully by a programmed laser puller. The Faraday adsorptions of oxygen and iodine, and the underpotential deposition of lead on the gold nanoelectrodes were investigated. The results showed that the active areas of nanoelectrodes were dramatically higher than their appearant geometry areas, which is caused by the surface diffusion of adsorptive species from the nanoscale gold/electrolyte interface to the adjacent gold surface.

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The Flip-Flop Behavior Of Acetonitrile At Au Electrode Surface Investigated By Sum Frequency Generation Vibrational Spectroscopy, Zhi Huang, Xin Tang, Gang-Hua Deng, En-Cai Zhou, Hong-Fei Wang, Yuan Guo May 2011

The Flip-Flop Behavior Of Acetonitrile At Au Electrode Surface Investigated By Sum Frequency Generation Vibrational Spectroscopy, Zhi Huang, Xin Tang, Gang-Hua Deng, En-Cai Zhou, Hong-Fei Wang, Yuan Guo

Journal of Electrochemistry

The electrochemical interface between liquid acetonitrile and polycrystal gold electrode is investigated by in situ infrared visible sum frequency generation spectroscopy (SFG-VS). The structure of acetonitrile adsorbed at polycrystal gold electrode surface is studied as a function of electrode potential. The SFG spectra of CH3 group indicate acetonitrile orients in response to the electrode potential. The SFG signal of CH3 group turns lower as the electrode potential changes from -700mV to 300mV, and vanishes around the 300mV(pzc), then becomes a negative signal above 500mV, which indicates that the orientation is predominately with the CH3 group toward the metal between -700 …

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Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan May 2011

Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan

Journal of Electrochemistry

A simple and efficient electrochemical route was developed for the synthesis of flaked spindle-like CuO nanocrystals using aqueous electrolyte and Cu sacrificial anode (graphite as the cathode) in an undivided cell at a constant potential mode under room temperature. The morphologies, structure and component of CuO nanocrystals obtained were characterized by SEM, XRD, respectively. Flaked spindle-like CuO nanocrystals were successfully used to modify a GC electrode to detect H2O2 with cyclic voltammetry (CV) and amperometric (AC).The results showed that products were pure monoclinic CuO nanocrystals. The linear range for the determination of hydrogen peroxide is from 1.0 μmol?L-1 to 1.0 …

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Influence Of Tert-Butylpyridine On The Band Energetics Of Nanostructured Tio2 Electrodes And The Photoelectrochemical Properties Of Dye-Seneitized Electrodes, Shu-Ming Yang, Ji-Chao Wang, Hui-Zhi Kou, Hong-Bin Xue, Hong-Jun Wang, Yu-Ling Guo May 2011

Influence Of Tert-Butylpyridine On The Band Energetics Of Nanostructured Tio2 Electrodes And The Photoelectrochemical Properties Of Dye-Seneitized Electrodes, Shu-Ming Yang, Ji-Chao Wang, Hui-Zhi Kou, Hong-Bin Xue, Hong-Jun Wang, Yu-Ling Guo

Journal of Electrochemistry

The flat band edges (Efb) of nanostructured TiO2 electrodes in electrolyte solutions with tert-butylpyridine (TBP) of different concentrations have been determined with spectroelectrochemical technique. TBP played a role in band energetics of nanostructured TiO2 electrodes. The Efb values of -2.25, -2.46 and -2.62 V were determined in three 0.2 mol•L-1 tetrabutylammonium perchlorate (TBAP) acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L-1 TBP respectively. The addition of Li+ ions shifted Efb positively. The Efb values of -1.12, -1.22 and -1.30 V were determined in three 0.2 mol•L-1 LiClO4 acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L-1 TBP respectively. The …

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Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen May 2011

Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen

Journal of Electrochemistry

CO2 reduction on Cu(111) single crystal surfaces was studied using DFT calculations on the reaction energies and the minimum energy paths. The results indicated that the possible reaction paths for CO2 reduction on Cu(111) surface are CO2(g) + H* → COOH* → (CO +OH)*, (CO + H)* → CHO*, CHO + H → CH2O* → (CH2 + O)*, CH2* + 2H* → CH4 or 2CH2* → C2H4. On Cu(111) surface, the reaction rate is controlled by steps of CH2O* → (CH2 + O)*, CO2(g) + H* → COOH → (CO +OH)* and (CO + H)* → CHO*. In addition, the …

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Self-Assembling Organic Semiconductors With Tunable Electronic Properties Based On Novel Asymmetric Phenazine And Bisphenazine, Kyoungmi Jang May 2011

Self-Assembling Organic Semiconductors With Tunable Electronic Properties Based On Novel Asymmetric Phenazine And Bisphenazine, Kyoungmi Jang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Current demands in the area of organic semiconductors focus on both electronic and self-assembling properties. Particularly, one-dimensionally grown nanostructures of small organic semiconductors have drawn much attention for nanodevice fabrication. Self-assembly through various intermolecular interactions has been widely used to produce one-dimensionally grown nanostructures which can be induced by various methods such as rapid solution dispersion, a phase transfer method, vapor annealing, crystallization, and organogelation in conjunction with proper molecular design. Controlling the morphology of the nanostructures plays an important role in achieving desirable properties in optoelectronic device applications. While significant advancements have been made in developing molecular architectures for …

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New Interfacial Nanochemistry On Sensory Bioscaffold-Membranes Of Nanobelts, Feng Chen May 2011

New Interfacial Nanochemistry On Sensory Bioscaffold-Membranes Of Nanobelts, Feng Chen

Graduate Theses and Dissertations

Nanostructured bioscaffolds and biosensors are evolving as popular and powerful tools in life science and biotechnology, due to the possible control of their surface and structural properties at the nm-scale. Being seldom discussed in literature and long-underexploited in materials and biomedical sciences, development of nanofiber-based sensory bioscaffolds has great promises and grand challenges in finding an ideal platform for low-cost quantifications of biological and chemical species in real-time, label-free, and ultrasensitive fashion. In this study, titanate nanobelts were first of all synthesized, from hydrothermal reactions of a NaOH (or KOH solution) with TiO2 powder, to possess underexploited structure and surface …

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Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng Feb 2011

Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng

Journal of Electrochemistry

The electrochemical behavior and electrocatalytic oxidation of hydrazine on rutin multiwall carbon nanotubes modified glassy carbon electrode were studied by cyclic voltammetry.The experimental results indicated that the electrode exhibits good electrocatalytic activity to hydrazine at a reduced oxidation potential of 262 mV.The amperometric response of the modified electrode showed linear increase after successive addition of hydrazine in the concentration range of 2.5×10-6~1.0×10-4 mol·L-1 with a detection limit of 5×10-7 mol·L-1.

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Applications Of Raman Spectroscopy Technique In Lithium Ion Batteries, Liang Zhao, Yong-Sheng Hu, Hong Li, Zhao-Xiang Wang, Hong-Xing Xu, Xue-Jie Huang, Li-Quan Chen Feb 2011

Applications Of Raman Spectroscopy Technique In Lithium Ion Batteries, Liang Zhao, Yong-Sheng Hu, Hong Li, Zhao-Xiang Wang, Hong-Xing Xu, Xue-Jie Huang, Li-Quan Chen

Journal of Electrochemistry

The Raman spectroscopy has been widely used in the study of lithium ion batteries.In this short review,we gave some examples of the applications of Raman spectroscopy in the study of electrode materials including carbonaceous materials,spinel LiMxMn2-x O4,LiFePO4,as well as polymer electrolytes,room temperaturemolten salt electrolytes and the solid-electrolyte interphase layers.The advantages and disadvantages of the ex-situ and in-situ Raman spectrum techniques are discussed.Using new Raman techniques to investigate Li-ion batteries are suggested.

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A Titanium-Supported Nanoporous Pd Electrocatalyst For Methanol Oxidation, Feng-Juan Niu, Qing-Feng Yi Feb 2011

A Titanium-Supported Nanoporous Pd Electrocatalyst For Methanol Oxidation, Feng-Juan Niu, Qing-Feng Yi

Journal of Electrochemistry

Titanium-supported nanoporous palladium electrode(nanoPd /Ti) was prepared by a hydrothermal process in the presence of the ligand EDTA and using formaldehyde as reducing agent.SEM images showed that the size of Pd particles was about 60 nm and the Pd particles were connected with each other to form a three-dimensional network structure.Cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were applied to evaluate the electrocatalytic activity of the nanoPd/Ti electrode towards methanol oxidation in alkaline solution.CV results showed that the nanoPd /Ti electrode presented high anodic peak densities and a low onset potential for methanol oxidation.Also nanoPd /Ti electrode showed excellent CO tolerance …

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Rh1−Xpdxnanoparticle Composition Dependence In Co Oxidation By Oxygen: Catalytic Activity Enhancement In Bimetallic Systems, James Russell Renzas, Wenyu Huang, Yawen Zhang, Michael E. Grass, Dat Tien Hoang, Selim Alayoglu, Derek R. Butcher, Franklin Tao, Zhi Liu, Gabor A. Somorjai Jan 2011

Rh1−Xpdxnanoparticle Composition Dependence In Co Oxidation By Oxygen: Catalytic Activity Enhancement In Bimetallic Systems, James Russell Renzas, Wenyu Huang, Yawen Zhang, Michael E. Grass, Dat Tien Hoang, Selim Alayoglu, Derek R. Butcher, Franklin Tao, Zhi Liu, Gabor A. Somorjai

Wenyu Huang

Bimetallic 15 nm Rh1−xPdxnanoparticle catalysts of five different compositions and supported on Si wafers have been synthesized, characterized using TEM, SEM, and XPS, and studied in CO oxidation by O2 in two pressure regimes: atmospheric pressure and 100–200 mTorr. The RhPd bimetallic nanocrystals exhibited similar synergetic effect of increased reaction activity at both atmospheric (760 Torr) and moderate (100–200 mTorr) pressures compared with pure Pd or Rh. The magnitude of the effect depends on the relative pressures of the CO and O2 reactant gases and the reaction temperature. The catalytic activity of the nanocrystals measured at moderate pressure is directly …

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Rh1−X Pd X Nanoparticle Composition Dependence In Co Oxidation By No, James Russell Renzas, Wenyu Huang, Yawen Zhang, Michael E. Grass, Gabor A. Somorjai Jan 2011

Rh1−X Pd X Nanoparticle Composition Dependence In Co Oxidation By No, James Russell Renzas, Wenyu Huang, Yawen Zhang, Michael E. Grass, Gabor A. Somorjai

Wenyu Huang

Bimetallic 15 nm Pd-core Rh-shell Rh1−x Pd x nanoparticle catalysts have been synthesized and studied in CO oxidation by NO. The catalysts exhibited composition-dependent activity enhancement (synergy) in CO oxidation in high NO pressures. The observed synergetic effect is attributed to the favorable adsorption of CO on Pd in NO-rich conditions. The Pd-rich bimetallic catalysts deactivated after many hours of oxidation of CO by NO. After catalyst deactivation, product formation was proportional to the Rh molar fraction within the bimetallic nanoparticles. The deactivated catalysts were regenerated by heating the sample in UHV. This regeneration suggests that the deactivation was caused …

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Nonuniformity In Lattice Contraction Of Bismuth Nanoclusters Heated Near Its Melting Point, A. Esmail, M. Abdel-Fattah, Hani E. Elsayed-Ali Jan 2011

Nonuniformity In Lattice Contraction Of Bismuth Nanoclusters Heated Near Its Melting Point, A. Esmail, M. Abdel-Fattah, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The structural properties of bismuth nanoclusters were investigated with transmission high-energy electron diffraction from room temperature up to 525 ± 6 K. The Bi nanoclusters were fabricated by thermal evaporation at room temperature on transmission electron microscope grids coated with an ultrathin carbon film, followed by thermal and femtosecond laser annealing. The annealed sample had an average cluster size of ∼14 nm along the minor axis and ∼16 nm along the major axis. The Debye temperature of the annealed nanoclusters was found to be 53 ± 6 K along the [012] direction and 86 ± 9 K along the [110] …

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Precise Control Of Highly Ordered Arrays Of Nested Semiconductor/Metal Nanotubes, Diefeng Gu, Helmut Baumgart, Kandabara Tapily, Pragya Shrestha, Gon Namkoong, Xianyu Ao, Frank Müller Jan 2011

Precise Control Of Highly Ordered Arrays Of Nested Semiconductor/Metal Nanotubes, Diefeng Gu, Helmut Baumgart, Kandabara Tapily, Pragya Shrestha, Gon Namkoong, Xianyu Ao, Frank Müller

Electrical & Computer Engineering Faculty Publications

Lithographically defined microporous templates in conjunction with the atomic layer deposition (ALD) technique enable remarkable control of complex novel nested nanotube structures. So far three-dimensional control of physical process parameters has not been fully realized with high precision resolution, and requires optimization in order to achieve a wider range of potential applications. Furthermore, the combination of composite insulating oxide layers alternating with semiconducting layers and metals can provide various types of novel applications and eventually provide unique and advanced levels of multifunctional nanoscale devices. Semiconducting TiO2 nanotubes have potential applications in photovoltaic devices. The combination of nanostructured semiconducting materials …

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Investigation Of Titanium Nitride As Catalyst Support Material And Development Of Durable Electrocatalysts For Proton Exchange Membrane Fuel Cells, Bharat Avasarala Jan 2011

Investigation Of Titanium Nitride As Catalyst Support Material And Development Of Durable Electrocatalysts For Proton Exchange Membrane Fuel Cells, Bharat Avasarala

Legacy Theses & Dissertations (2009 - 2024)

The impending energy and climatic crisis makes it imperative for human society to seek non-fossil based alternative sources for our energy needs. Although many alternative energy technologies are currently being developed, fuel cell technology provides energy solutions, which satisfy a wide range of applications. But the current fuel cell technology is far from its target of large scale commercialization mainly because of its high cost and poor durability. Considerable work has been done in reducing the cost but its durability still needs significant improvement. Of the various materials in a PEM fuel cell, the degradation of electrocatalyst affects its durability …

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