Semiconductor Nanocrystals: From Quantum Dots To Quantum Disks,
2012
University of Arkansas, Fayetteville
Semiconductor Nanocrystals: From Quantum Dots To Quantum Disks, Zheng Li
Graduate Theses and Dissertations
The bottom-up colloidal synthesis opened up the possibility of finely tuning and tailoring the semiconductor nanocrystals. Numerous recipes were developed for the preparation of colloidal semiconductor nanocrystals, especially the traditional quantum dots. However, due to the lack of thorough understanding to those systems, the synthesis chemistry is still on the empirical level. CdS quantum dots synthesis in non-coordinating solvent were taken as a model system to investigate its molecular mechanism and formation process, ODE was identified as the reducing agent for the preparation of CdS nanocrystals, non-injection and low-temperature synthesis methods developed. In this model system, we not only proved …
Derivative Couplings With Built-In Electron-Translation Factors: Application To Benzene,
2012
University of Texas Rio Grande Valley
Derivative Couplings With Built-In Electron-Translation Factors: Application To Benzene, Shervin Fatehi, Joseph E. Subotnik
School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)
Derivative couplings are the essential quantities at the interface between electronic-structure calculations and nonadiabatic dynamics. Unfortunately, standard approaches for calculating these couplings usually neglect electronic motion, which can lead to spurious electronic transitions. Here we provide a general framework for correcting these anomalies by incorporating perturbative electron-translation factors (ETFs) into the atomic-orbital basis. For a range of representative organic molecules, we find that our ETF correction is often small but can be qualitatively important, especially for few-atom systems or highly symmetric molecules. Our method entails no additional computational cost, such that ETFs are “built-in,” and it is equivalent to a …
Pcet With Bimetallic Systems,
2012
Department of Chemistry, The University of Texas at El Paso
Pcet With Bimetallic Systems, Maripaz A. Calderon, Dino Villagran
COURI Symposium Abstracts, Summer 2012
Electron-transfer (ET) is one of the simplest chemical events, yet it is a vital process for chemical reactivity. Proton-coupled electron transfer (PCET) is the concerted transfer of protons and electrons which is fundamental in chemical and biological systems and processes in electrochemistry, photosynthesis, and enzymatic activity. Similarly, mixed-valence (MV) systems are pervasive in nature and provide a platform for multiple electron transfers systems in nature. While both fields have been studied extensively, little work has been done on the intersection of the two. This project explores the elegant use of MV bimetallic systems through hydrogen-bonded networks. Using standard Schlenk and …
Novel Dyad-Fullerene Derivative Used As Acceptor With P3ht In Bulk Heterojunction Solar Cells,
2012
Saginaw Valley State University
Novel Dyad-Fullerene Derivative Used As Acceptor With P3ht In Bulk Heterojunction Solar Cells, Amber D. Berkobien, Luis Echegoyen, Maira Cerón, Danisha Rivera
COURI Symposium Abstracts, Summer 2012
Within the world of solar cells, research is rapidly uncovering potential solutions to the alternative energy issues by utilizing bulk-heterojunction cell techniques (Figure 1a) for low-cost and quick effective manufacturing. In this scope of research, a unique concept of donor-acceptor (D-A) system pairing as an acceptor within the bulk-heterojunction cell has been brought to light; a new concept of utilizing HOMO/LUMO pairings to create effective transport systems between a combination D-A acceptor and polymer donor is being optimized for maximum Photo-Conversion Efficiency (PCE). Due to a similar band gap relationship between the commonly reported PCBM and the novel dyad fullerene …
Development Of Novel Organocatalytic Cascade Reactions And Application In Organic Systheses,
2012
University of New Mexico
Development Of Novel Organocatalytic Cascade Reactions And Application In Organic Systheses, Xixi Song
Chemistry and Chemical Biology ETDs
The development of new catalytic reactions, particularly synthetically efficient cascade processes for the facile preparation of important molecular architectures, which otherwise are difficult to access via traditional methods, is of considerable significance. Toward this end, my Ph.D. work focuses on developing new organocatalytic reactions and their applications in organic syntheses. A novel direct organocatalytic stereoselective α-arylation methodology has been discovered. The cross-coupling-like products are assembled using simple enals and various brominated aromatic systems, such as p-bromophenols, bromonaphthols and 3-bromoindoles. The products have been applied in the concise photo-syntheses of [α]-annulated carbazoles. Moreover, an unexpected reaction has been identified with aliphatic …
A Proposed Palladium-Catalyzed Cycle For The Epoxidation Of Alkenes,
2012
University of New Mexico
A Proposed Palladium-Catalyzed Cycle For The Epoxidation Of Alkenes, Marie Vernell Parkes
Chemistry and Chemical Biology ETDs
Epoxides are an important chemical functional group, used in a wide variety of processes, from the small-scale production of pharmaceuticals to the large-scale production of propylene oxide. Current methods for production of epoxides require costly multi-step syntheses that use toxic or explosive reagents, result in low yields, and produce co-products that must be removed and often disposed. The development of an atom-efficient general method, preferably catalytic, for converting alkenes to epoxides using safe, cheap, and readily available molecular oxygen as the stoichiometric oxidant would be a great advance in both industrial and academic chemistry. Presented here is a proposed catalytic …
Preparation And Electrochemical Performance Of Tio2/Gns Nanocomposite As Anode Materials For Lithium-Ion Batteries,
2012
State Key Lab of Physical Chemistry of Solid Surfaces, Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
Preparation And Electrochemical Performance Of Tio2/Gns Nanocomposite As Anode Materials For Lithium-Ion Batteries, Lin-Lin Qin, Huan Zhang, Xiao-Jing Liu, Jian-Hui Xu, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong
Journal of Electrochemistry
The honeycomb-like porous TiO2/graphenes (TiO2/GNs) nanocomposite was prepared by a reflux method. SEM and TEM results showed that nanosized anatase TiO2 (about 5~10 nm) were dispersed uniformly on the surface of the GNs. The TiO2/GNs composite showed excellent rate and cycling performance: A stable charge capacity of 169.5 mAh·g-1 was obtained at 30C, and can restore to 241.7 mAh·g-1 while current went back to 1C. The stable charge capacity of TiO2/GNs nanocomposite electrode up to 201.9 mAh·g-1 was achieved at 10C in the first cycle, and could be …
An Overview Of Electrode Materials In Microbial Fuel Cells,
2012
Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063, China;
An Overview Of Electrode Materials In Microbial Fuel Cells, Su-Qin Ci, Na Wu, Zhen-Hai Wen, Jing-Hong Li
Journal of Electrochemistry
Microbial fuel cells (MFCs) are devices that can directly convert organic chemical energy into electrical energy with microbial as catalysts. MFCs are a promising bio-electrochemical system with the potential to degrade organic sewage and produce electricity. This article supplies a critical and comprehensive review for the electrode materials concerning about anode and cathode in MFCs, including the fabrications, functional modifications and surface constructions of electrode materials, as well as their applications in MFCs. Additionally, the existing problems of electrode materials in current MFCs have been demonstrated in order to provide the guideline for exploring the next-generation electrode materials for MFCs.
Protonization Of Amino Functional Groups Confined In Nanochannels,
2012
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering Nanjing University, Nanjing 210093,China
Protonization Of Amino Functional Groups Confined In Nanochannels, Hong-Li Gao, Kai-Lin Zhou, Chen Wang, Su-Juan Li, Hui Zhang, Xing-Hua Xia
Journal of Electrochemistry
Protonization process is the key step of acid-base reaction and occurs in many biological processes. Study of the protonization process of molecules and/or functional groups in confined conditions would assist understanding in the acid-base theory and confinement effect of biomolecules. In this paper, we developed a novel approach to study protonization of functional groups in porous anodic alumina array nanochannels by measuring the flux of electrochemical active probes using an Au film electrochemical detector sputtered at the end of the nanochannels. The protonization status of the surface functional groups in nanochannels can change the surface charges and further modulate the …
Preparation And Electrochemical Performance Of Tin@Mno Fibers By Coaxial Electrospinning,
2012
Qingdao University of Science and Technology, Qingdao 266042, Shandong, China;
Preparation And Electrochemical Performance Of Tin@Mno Fibers By Coaxial Electrospinning, Chao-Qun Shang, Hai-Yan Yang, Xin-Hong Zhou, Zhong-Lei Man, Peng-Xian Han, Jian-Hua Yao, Yu-Long Duan, Guang-Lei Cui
Journal of Electrochemistry
In this study, the titanium nitride (TiN) @manganese oxide (MnO) core-shell structured fibers were prepared by the coaxial electrospinning using tetrabutyl titanate and manganese acetylacetonate as raw materials, and polyvinylpyrrolidone (PVP) as the template. And then the fibers were annealed in ammonia to finally obtain the coaxial TiN@MnO fibers. XRD, FESEM, TEM, EDX and physical adsorption instrument were used to characterize the phase structure, morphology, composition and specific surface areas and pore sizes of the samples. It was demonstrated that the as-synthesized TiN@MnO fibers possessed coaxial structure with a surface area of 16 m2·g-1. As indicated …
Novel Molten-Salt Electrolysis Processes Towards Low-Carbon Metallurgy,
2012
School of Resouree and Environmental Sciences, Wuhan liniversity, Wuhan 430072, China
Novel Molten-Salt Electrolysis Processes Towards Low-Carbon Metallurgy, Wei Xiao, Hua Zhu, Hua-Yi Yin, De-Hua Wang
Journal of Electrochemistry
This review focuses on recent developments in molten-salt electrolytic metallurgical processes with respect to 1) high-efficiency metallurgical technologies via electrolytic reduction of solid oxides in molten chlorides and 2) zero-carbon-footprint electrochemical splitting metallurgical technologies. Initiating with an introduction on dynamic solid/solid/liquid three-phrase interlines electrochemistry for electrochemical reduction of solid cathode, the former aspect is discussed in terms of facilitating mass transfer throughout solid cathode, one-step production of functional alloy powders with the assistance of under-potential electroreduction of active metals and near-net-shape production of metal/alloy components. Whilst the latter is summarized by introducing some zero-carbon molten-salt electrolytic technologies including electro-splitting of …
Comments On Internal Alternating Current Resistance Test Standard And Methods Of Lithium-Ion Batteries,
2012
Weifang Wina Green Power Co., Ltd., Shouguang 262705, Shandong, China
Comments On Internal Alternating Current Resistance Test Standard And Methods Of Lithium-Ion Batteries, Ya-Li Zhang, Sen Xin, Yu-Guo Guo, Li-Jun Wan
Journal of Electrochemistry
The sustainable development of energy and environment is one of the most influential issues of this century. Batteries, especially secondary batteries are important for powering out daily life. However, in many practical applications, such as in electric vehicles and hybrid electric vehicles, batteries should be used in packs and the performance consistency of each battery in the pack should be taken into consideration. As one of the performance parameters being used to characterize the battery consistency, internal resistance is of great importance to the industrial fabrication and the use of batteries. Currently, internal resistance tests of secondary batteries, such as …
Methodological Significance Of "Property-Activity Relationship" For Catalyst Studies,
2012
Hubei Key Lab ofElectrochemical Power Sources, College of Chemistry and Moleeular Sciences, Wuhan lniversity, Wuhan 430072, China
Methodological Significance Of "Property-Activity Relationship" For Catalyst Studies, Jun-Tao Lu, Li Xiao, De-Li Wang, Yu-Bao Sun, Yan-Ge Suo, Lin Zhuang
Journal of Electrochemistry
Instead of attempting the structure-activity relationship (SAR), which is commonly regarded as the core problem for catalyst studies, this paper highlights the methodological significance of “property-activity relationship (PAR)”. The “property” here refers to an index （such as the adsorption energy of an intermediate） or a group of indexes reflecting the behavior of a catalyst which interacts with reactants or intermediates, and is a bridge between structure and activity. Because property is related to activity more directly than structure to activity, PAR should be simpler, less difficult and, therefore, more feasible to be accessed than SAR. Once the key property is …
Simple Analysis And Possible Solutions Of The Unusual Interfacial Reactions In Li-S Batteries,
2012
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China;
Simple Analysis And Possible Solutions Of The Unusual Interfacial Reactions In Li-S Batteries, Xin-Ping Ai, Yu-Liang Cao, Han-Xi Yang
Journal of Electrochemistry
Rechargeable Li-S batteries are a promising power source with realizable energy densities several times higher than current Li-ion batteries. However, the capacity utilization and cycling stability of the existing Li-S technologies are still insufficient for battery applications. The causes for the electrochemical instability of this redox system arise probably from the changes in the surface structures and electrochemical microenvironments of the Li anode and sulfur cathode during charge-discharge reactions, which includes the frustrated electron transfer in the sulfur-carbon interface, the dissoluble diffusion of the polysulfide intermediates, and the shuttle reaction inbetween the sulfur and Li electrodes. To deal with these …
Application Of First Principles Calculations In Anode Materials For Lithium Ion Batteries,
2012
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Nankai University, Tianjin 300071,China
Application Of First Principles Calculations In Anode Materials For Lithium Ion Batteries, Tian-Ran Zhang, Dai-Xin Li, Si-Qi Yang, Zhan-Liang Tao, Jun Chen
Journal of Electrochemistry
First principles calculations play an important role in the study and development of new materials for lithium batteries. In this paper, we review the application of first principles calculations in the design of anode materials, including the modeling of the interaction of lithium in the anode materials, capacity, voltage, electrochemical reaction process, diffusion, rate capability, the relationship between the structure and properties, and the experimental phenomena interpreting. Based on the discussions, we emphasize on the importance of first principles calculations and demonstrate their requirement for further development.
Preparation And Characterization Of Prussian Blue Modified Nanoelectrode,
2012
State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Preparation And Characterization Of Prussian Blue Modified Nanoelectrode, Wei Wang, Bao-Fa Su, Dong-Ping Zhan
Journal of Electrochemistry
The Pt nanoelectrodes were fabricated by using a laser-based pipet puller and the recessed nanoelectrodes were prepared by etching of disk Pt nanoelectrodes wtih high frequency ac voltage. Prussian blue microcrystal was synthesized electrochemically on the both disk and recessed Pt nanoelectrodes. The strength of mechanical adhesion for the Prussian blue microcrystal on the nanoelectrode was enhanced. A novel method for the controllable synthesis of single particle is proposed, which has potential applications in modified electrodes and single particle electrocatalysis.
On The Molecular Mechanism Of Electron Transfer Of Cytochrome C Modulated By Gold Nanoparticles In Nano-Sandwich Architecture,
2012
Department of Chemistry, Northeast Normal University, Changchun 130024, China
On The Molecular Mechanism Of Electron Transfer Of Cytochrome C Modulated By Gold Nanoparticles In Nano-Sandwich Architecture, Shou-Rui Lin, Li-Xu Wang, Xiu-E Jiang, Li-Ping Guo
Journal of Electrochemistry
The effects of adsorbed gold nanoparticles on the surface-enhanced infrared absorption (SEIRA) difference spectra of redox-induced cytochrome (Cyt) c in AuNPs/Cyt c/Au sandwich architecture were monitored by SEIRA spectroscopy. The results indicated that the intensity of SEIRA difference spectrum for the vibration of the heme was significantly increased due to the adsorption of gold nanoparticles on the Cyt c. This was induced by the electron transfer between the heme and the gold nanoparticles, which also promoted electron transfer of adsorbed protein. This study suggested a new technique for optimizing the electrochemical property of adsorbed protein.
The Electrocatalytic Performance Of Pd Catalysts Supported On Pvp Modified Mwcnts For Formic Acid Oxidation,
2012
1. State Key Laboratory of Electro-Analytical Chemistry, Laboratory of Advaneed Power Sources .Changchun Institute of Applied Chemistry, Chinese Aeademy of Seienees, Changchun 130022, China; 2. Graduate School ofthe Chinese Academy of Sciences, Beijing 100049, China
The Electrocatalytic Performance Of Pd Catalysts Supported On Pvp Modified Mwcnts For Formic Acid Oxidation, Jing Zhang, Xiao Zhao, Chang-Peng Liu, Wei Xing
Journal of Electrochemistry
In this paper the MWCNTs were modified by Poly (N-vinyl-2-pyrrolidone) (PVP) to support Pd nanoparticles, which were used as the catalyst for formic acid electrooxidation. And the performance of Pd/PVP-MWCNTs catalysts was studied by electrochemical measurements. The observations from Fourier transforms infrared spectrometer (FTIR) and transmission electron microscopy (TEM) illustrated that the Pd nanoparticles with a small size and narrow size distribution were highly dispersed on PVP-MWCNT support. Therefore, the Pd/PVP-MWCNTs catalysts showed excellent catalytic activity for formic acid electrooxidation.
Synthesis Of Spherical Ni3S4 By Solvothermal Method As Supercapacitor Electrodes,
2012
Institute of New Energy and Material Chemistry, Key Laboratory of Advanced Energy MaterialsChemistry-Ministry of Education, Nankai University, Tianjin 300071,China
Synthesis Of Spherical Ni3S4 By Solvothermal Method As Supercapacitor Electrodes, Qing-Na Huan, Li-Fang Jiao, Qing-Hong Wang, Hong-Mei Du, Jia-Qin Yang, Wen-Xiu Peng, Yi-Jing Wang, Hua-Tang Yuan
Journal of Electrochemistry
The Ni3S4 microspheres have been synthesized via a facile solvothermal method. The crystal structure and surface morphology are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microspherical Ni3S4 exhibits good electrochemical capacitance validated by electrochemical measurements. The specific capacities of 1120.6 F∙g-1 at 0.5 A∙g-1 and 433.4 F∙g-1 at 4 A∙g-1 with the capacitance retention of 89.37 % and 84.88 % were obtained after 1000 cycles, respectively. The electrochemical reaction is expected due to the transformation of Ni(OH)2 and NiOOH based on the XRD, XPS and CV …
Performnces Of Lini0.5Mn0.5O2 Thin Film Electrodes Prepared By Pulsed Laser Deposition,
2012
Nanjing liniversily ofScience and Technology, School of Materials Seience and kingineering, Nanjing 210094, China
Performnces Of Lini0.5Mn0.5O2 Thin Film Electrodes Prepared By Pulsed Laser Deposition, Yun-Hai Wan, Guo-Liang Yuan, Hui Xia
Journal of Electrochemistry
The all-solid-state thin-film Li-ion batteries with high energy density, power density and temperature stability are the ideal power sources for microelectronic devices. Developing new thin-film cathodes with large specific capacity is the key to their practical applications. The LiNi0.5Mn0.5O2 with a layered structure has a higher reversible capacity and better structural stability compared with traditional LiCoO2 cathode material. In this work, the LiNi0.5Mn0.5O2 thin film cathodes were prepared by pulsed laser deposition. The effects of substrate material and temperature on the microstructure, surface morphology and composition of the thin …
