Materials Chemistry Commons^™

Surface Ehancement Of Nickel Ions On Cyanide Free Immersion Gold Deposited From A Chloroauric Acid-Choline Chloride Solution On Medium-Phosphorus Nickel, Tian-Yu Xu, Shi-Ying Wang, Wen-Chang Wang, Zhi-Dong Chen

Journal of Electrochemistry

The nickel ions (Ni²⁺) were introduced into choline chloride (ChCl) cyanide free immersion gold solution to improve the surface quality of electrodeposition on medium-phosphorus nickel substrate. The addition of Ni²⁺ had no significant impact on the plating speed. However, the hyperactive corrosion of nickel substrate could be effectively alleviated by the addition of 500 mg·L^-1 NiCl₂·6H₂O, and the surface morphology of gold coating could be greatly improved. The choline chloride bath has great potential for industrial production due to its high Ni²⁺ carrying capacity (2000 mg·L^-1) and superior applicability …

Preparation Of Nis2 Nanosheet And Its Application In Asymmetric Supercapacitor, Yuan-You Wang, Ya-Nan Liu, Dang-Qin Jin

Journal of Electrochemistry

In this work, the NiS₂ nanosheets have been synthesized using Ni(OH)₂  as a precursor through a sacrificial template method. The microstructure and chemical composition of as-prepared NiS₂ were characterized by XRD, EDS, BET, SEM and TEM techniques. The results showed that both Ni(OH)₂  and NiS₂  were composed of nanoplates. The electrochemical tests revealed that NiS₂ exhibited the high specific capacitance of 1067.3 F•g^-1 at a current density of 1 A•g^-1 and excellent rate performance. Furthermore, in order to evaluate the practical application of NiS₂, an asymmetric supercapacitor, NiS₂ as …

Core-Shell Pd@Pt Ultrathin Nanowires As Durable Oxygen Reduction Electrocatalysts, Xin Wang, Yun-Jie Xiong, Liang-Liang Zou, Qing-Hong Huang, Zhi-Qing Zou, Hui Yang

Journal of Electrochemistry

This paper describes a simple CO-assisted reduction approach for the controllable synthesis of ultrathin Pd nanowires along the one-dimensional (1D) direction. Ultrathin Pt films from one to several atomic layers were successfully decorated onto ultrathin Pd nanowires by utilizing Cu UPD deposition, and followed by in-situ redox replacement reaction of UPD Cu by Pt. The core–shell structure and composition of the Pd@Pt ultrathin nanowires have been verified using transmission electron microscopy and energy dispersive X-ray spectrometry. The core–shell Pd@Pt ultrathin nanowires exhibited comparative electrocatalytic activity and improved durability for the oxygen reduction reaction in comparison with commercial Pt black. The …

Three-Dimensional Nanomaterials For Supercapacitor Applications: From Metal Oxides To Metal Phosphides, Zhi Zheng

LSU New Orleans Theses and Dissertations

Over the past few years, energy storage devices have received tremendous interest due to the increasing demand for sustainable and renewable energy in modern society. Supercapacitors are considered as one of the most promising energy storage devices because of their high power density and long cycle life. However, low energy density remains as the main shortcoming for supercapacitors. The overall performance of supercapacitors is predominantly determined by the characteristics of the electrodes. Specifically, constructing nanostructured electrode material has been proven as an efficient way to improve the performance by providing large surface area and short ionic and electronic diffusion paths. …

Investigating Scalable Manufacturing Of High-Conductivity Wires And Coatings From Ultra-Long Carbon Nanotubes, Pouria Khanbolouki

Mechanical Engineering ETDs

Carbon nanotubes (CNTs) are a promising candidate for next generation of electrical wirings and electromagnetic interference (EMI) shielding materials due to their exceptional mechanical and electrical properties. Wires and coatings from ultralong nanotubes that are highly crystalline, well-aligned and densely packed can achieve this goal. High-performance CNT conductors will be relatively lightweight and resistant to harsh conditions and therefore can potentially replace current conductors in many industries including aerospace, automotive, gas and oil.

This thesis investigates a new manufacturing approach, based on conventional solution coating and wire drawing methods, to fabricate high conductivity wires and coatings from ultra-long carbon nanotubes. …

Density Functional Investigation On Cathode/Electrolyte Interface In Solid-State Lithium Batteries, Xuelong Wang, Ruijuan Xiao, Yong Xiang, Hong Li, Liquan Chen

Journal of Electrochemistry

The rapidly expanding application of lithium ion batteries stimulates research interest on energy storage devices with higher energy density, better safety and faster charge/discharge speed. All-solid-state lithium batteries have been considered as promising candidates because of their fewer side reactions and better safety compared with conventional lithium-ion batteries with organic liquid electrolytes. Looking for well-matched electrode/electrolyte interfaces is one of the keys to ensuring good comprehensive performance of solid-state lithium batteries. In this report, with the aid of first-principles simulations, the local structure and lithium ions transportation properties of electrolyte surfaces and cathode/electrolyte interfaces are investigated. The β-Li₃PS …

Effects Of Surface Modification Modes On Proton-Over-Vanadium Ion Selectivity Of Nafion®Membrane For Application In Vanadium Redox Flow Battery, Qing-Long Tan, Hai-Ning Wang, Shan-Fu Lu, Da-Wei Liang, Chun-Xiao Wu, Yan Xiang

Journal of Electrochemistry

The effect of surface modification modes on proton-over-vanadium ion selectivity was studied by spin-coating chitosan-Phosphotungstic Acid (PWA) as a single or double layer on Nafion membrane surface. To suppress the vanadium ions permeation through the Nafion? membrane in a vanadium redox flow battery (VRFB), the single surface-modified Nafion membrane (Nafion/chitosan-PWA)S and double surface-modified Nafion membrane (Nafion/chitosan-PWA)D demonstrated a 89.9% and 92.7% reduction of vanadium ion permeability in comparison with pristine Nafion, respectively. The (Nafion/chitosan-PWA)D exhibited betterhigher selectivity between proton and vanadium ions than the (Nafion/chitosan-PWA)S at the same layer thickness. Furthermore, the columbic efficiency for the VRFB single cell based …

Surface Chemical Properties Of Mo2C, W2C, Mo2N And W2N Probed With Co, Co2 And O2 Adsorption: A Dft Analysis, Jingyun Ye, Tianyu Zhang, Lingyun Xu, Shuxia Yin, Krishanthi Weerasinghe, Pamela Ubaldo, Ping He, Qingfeng Ge

Journal of Electrochemistry

Transition metal carbides and nitrides are attractive materials for electrodes in many electrochemical energy storage and conversion applications. In the present study, we use density functional theory slab calculations to characterize the surface chemical properties of molybdenum (Mo) and tungsten (W) carbides and nitrides, namely, Mo₂C, W₂C, Mo₂N and W2N with the adsorption of CO, CO₂ and O₂. These probing molecules provide measures of in both acidity/basicity and redox property of for the surfaces of these carbides and nitrides. Our results show that Lewis basic sites were responsible for CO_{2 …}

A New Type Carbon Composited Molybdenum Doped Vanadium Oxide Nanowires As A Cathode Material For Sodium Ion Batteries, Guang-Rui Zhang, Li-Qiang Hu, Bao-Zhu Zhang

Journal of Electrochemistry

In recent years, the development of lithium ion batteries (LIBs) has been limited due to the insufficient lithium resource and increasing cost. As a promising candidate, sodium ion batteries (SIBs) with the similar electrochemical mechanism and lower cost than LIBs are developing rapidly. However, as a result of the larger radius of Na⁺ compared with Li⁺, the crystalline structures of the most electrode materials are damaged severely during the intercalation of Na⁺, which limits the electrochemical properties of SIBs. Thus, developing new types of electrode materials for SIBs is particularly important. Among the cathode materials, …

Electrocatalysis Of Nanotin Dioxide In The Battery Reaction Of Zinc-Nitrobenzene, Xu-Guo Tu, Xiang-Yu Ma, Rui-Nan He, Xiao-Juan Wang, Chen Ling, Yun-Xia Sun, Song Chen

Journal of Electrochemistry

The tin dioxide (SnO₂) nanoparticles were synthesized by using a simple hydrothermal route in the presence of tetrapropyl ammonium bromide (TPAB) as a surfactant. Accordingly, the titanium mesh based SnO₂ catalyst electrode was prepared. The morphologies and structures of SnO₂ nanostructures were characterized by scanning electron microscopy and X-ray diffraction spectrometry. The influences of reactant concentration, reaction temperature and time on the morphology of the products were investigated in detail. The electrocatalytic performance of SnO₂ for the reduction of nitrobenzene with zinc was studied. Possible formation process and growth mechanism for such hierarchical SnO_{2 …}

Characteristics And Mechanism For The Simons Electrochemical Fluorination Of Methanesulfonyl Fluoride, Wen-Lin Xu, Bao-Tong Li, Da-Wei Wang, Ya-Qiong Wang

Journal of Electrochemistry

The characteristics and mechanism for the Simons electrochemical fluorination processes were investigated during the electrochemical fluorination of CH₃SO₂F to CF₃SO₂F. The results showed that the reaction mechanism for the electrochemical fluorination of organic compounds to organic fluorides was the same as that of chemical fluorination processes using fluorinating agents such as CoF₃. The electrochemical fluorination in anhydrous HF was a heterogeneous process, and nickel fluorides on the surface of the nickel anode played the role of a mediator in the Simons process to transfer oxidation potential from the anode to …

Novel Composites Between Nano-Structured Nickel Sulfides And Three-Dimensional Graphene For High Performance Supercapacitors, Xiaomin Wang, Huanglin Dou, Zhen Tian, Jiujun Zhang

Journal of Electrochemistry

In this paper, a three-dimensional graphene (3DG) network grown on nickel foam was employed as a template for synthesizing graphene-based composite materials of supercapacitor electrode. The composites (crystal Ni₃S₂ nanorods on the surface of 3DG (abbreviated as Ni₃S₂/3DG)) were obtained through a one-step hydrothermal reaction. The morphological and structural evolution of the Ni₃S₂/3DG composites were investigated by SEM, TEM, XRD and Raman spectroscopy. Detailed electrochemical characterization showed that the Ni₃S₂/3DG-coated electrodes exhibited both a specific capacitance as high as 1825 F·g^-1 at 5 mV·s …

Comparative Studies Of Fe, Ni, Co And Their Bimetallic Nanoparticles For Electrochemical Water Oxidation, Maduraiveeran Govindhan, Brennan Mao, Aicheng Chen

Journal of Electrochemistry

The design of efficient, durable, and earth-abundant electrocatalysts via environmentally compatible strategies for the oxygen evolution reaction (OER) is a vital for energy conversion processes. Herein we report a facile approach for the fabrication of low-cost and earth abundant metal catalysts, including iron (Fe), nickel (Ni), cobalt (Co), CoNi, and CoFe nanoparticles (NPs) on titanium (Ti) substrates through a one-step electrochemical deposition. Field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) spectrocopy, X-ray photoelectron spectroscopy (XPS), and electrochemical techniques were employed to characterize these nanoparticles. Our electrochemical results revealed that among the five synthesized nanomaterials, the …

Comparison Of Oxygen Reduction Reaction Activity Of Pt-Alloy Nanocubes, Yongan Tang, Lin Dai, Shouzhong Zou

Journal of Electrochemistry

Alloying Pt with the first row non-noble transition metals has been demonstrated to increase the catalytic activity toward oxygen reduction reaction (ORR), which is the cathode reaction of the proton exchange membrane fuel cells (PEMFCs) and metal-air batteries. However, how much the ORR activity improvement comes from the alloying elements remains controversial. In this paper, the nanocubes of PtMn, PtFe, PtCo, and PtNi with the similar size and composition were prepared and their ORR activities were explored, in order to investigate the effects of alloying elements on the catalytic activity. The use of cubic shape particles minimizes the contribution to …

Resistive-Pulse Analysis Of Single Phospholipid Vesicles Using Quartz Nanochannels, Jonathan T. Cox, Bo Zhang

Journal of Electrochemistry

We report the uses of resistive-pulse method and quartz nanochannels for the detection and size analysis of single vesicles. Cylindrical shape quartz nanochannels have been used to detect single phospholipid vesicles ranging from 100 to 300 nm and polystyrene nanoparticles ranging from 170 to 400 nm in diameter. Translocations of single vesicles and nanoparticle were detected as individual square current pulses, which could be used to determine particle size. Our results show excellent agreement between the particle/vesicle sizes obtained from nanochannels and those from dynamic light scattering (DLS) and scanning electron microscopy (SEM). This electronic-based method was found to be …

Electrodeposition Of Ruo2 Layers On Tio2 Nanotube Array Toward Co2 Electroreduction, Bei Jiang, Lina Zhang, Xianxian Qin, Wenbin Cai

Journal of Electrochemistry

RuO₂/TiO₂ composite materials have multitude of electrocatalytic applications including but not limited to CO₂ reduction reaction (CO₂RR). RuO₂/TiO₂ electrodes were previously prepared by repetitive coating and thermal decomposition (TD) of a Ru(III) precursor solution on Ti substrate. In this work, electrochemical potential cycling is applied to deposit amorphous RuO₂ (α-RuO₂) layers onto TiO₂ nanotube array (TNA) (RuO₂^CV/TNA) preformed on Ti foil. SEM, GIXRD, and voltammetry are applied to characterize the structures of the resulting RuO₂^CV/TNA. Ru loading on the RuO_{2 …}

Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Marcelo I. Guzman, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali

Chemistry Faculty Publications

How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence …

Aligning Electronic Energy Levels On The Anatase Tio2(101) Surface, Jun-Jie Zhao, Jun Cheng

Journal of Electrochemistry

As one of the most commonly-used materials for photocatalysis and solar energy conversion, titanium dioxide (TiO₂) has been extensively studied for more than 40 years. Its photoelectrochemical activity crucially depends on the band positions at the interface. In this work, the valence band maximum (VBM) and conduction band minimum (CBM) of a model TiO₂ surface are computed using the standard work function method at the level of Perdew-Burke-Ernzerhof (PBE) density functional, which are then converted to the scale of the standard hydrogen electrode (SHE) by subtracting the absolute SHE potential. Comparing with the rutile TiO₂(110) …

Direct Electrochemistry Of Glucose Oxidase Based On Ws2 Quantum Dots And Its Biosensing Application, Chen-Lu Li, Hua-Ping Peng, Zhong-Nan Huang, Yi-Lun Sheng, Pei-Wen Wu, Xin-Hua Lin

Journal of Electrochemistry

In this study, a novel electrochemical glucose biosensor has been developed by immobilizing glucose oxidase (GOx) on tungsten disulfide quantum dots (WS₂ QDs) on the surface of glassy carbon electrode (GCE). Transmission electron microscopy, UV-vis spectroscopy and cyclic voltammetry were employed to characterize the morphology, structure, and electrochemical behaviors of the as-prepared WS₂ QDs and the biofilm modified electrode. The results suggested that the WS₂ QDs could accelerate the electron transfer between the electrode and the immobilized enzyme, which enabled the direct electrochemistry of GOx without any electron mediator. Besides, the immobilized GOx in WS₂ QDsfilm …

Synthesis, Characterization, And Enhanced Magnetic Properties Of Iron Carbide Nanomaterials, Brent M. Williams

Theses and Dissertations

Permanent magnets are classified as hard magnetic materials with the main purpose of generating flux for applications such as electric motors, turbines, and hard drives. High coercivity, magnetic remanence, and saturation values with high stability are some of the requirements for permanent magnets. Rare-earth magnets including neodymium and samarium based magnets are known to have superior magnetic properties due to their high magnetocrystalline anisotropy. However, due to the price of rare-earth materials development of alternate permanent magnets composed of inexpensive materials is an ongoing process. Previously cobalt carbide (Co_xC) have shown promise as a potential rare-earth free magnet …

Deconvolving The Steps To Control Morphology, Composition, And Structure, In The Synthesis Of High-Aspect-Ratio Metal Oxide Nanomaterials, Lei Yu

Theses and Dissertations--Chemistry

Metal oxides are of interest not only because of their huge abundance but also for their many applications such as for electrocatalysts, gas sensors, diodes, solar cells and lithium ion batteries (LIBs). Nano-sized metal oxides are especially desirable since they have larger surface-to-volume ratios advantageous for catalytic properties, and can display size and shape confinement properties such as magnetism. Thus, it is very important to explore the synthetic methods for these materials. It is essential, therefore, to understand the reaction mechanisms to create these materials, both on the nanoscale, and in real-time, to have design control of materials with desired …

Investigation On Laser Induced Deposition Of Cu-Based Materials At [Bmim]Bf4/Pt Electrode Interface, Min-Min Xu, Jin-Hua Mei, Jian-Lin Yao, Ren-Ao Gu

Journal of Electrochemistry

By controlling the negative potential, Cu-based materials were deposited at the [BMIm]BF₄/Pt electrode interface under the laser irradiation. The effects of laser power and irradiation time on the yield of deposition products were studied by using different laser powers and different irradiation time. The product yield could be directly determined by the size of deposition point through the observation from the optical microscope. Further mechanism study combined with the formula deduced that the thermal effect of the laser could make the electrode surface temperature rise 110 degrees, which can promote the occurrence of electrodeposition. By SEM characterization, the …

An Stm Study On The Structure Of Pt(100)/Ionic Liquid Omipf6 Interface, Jin Peng, Mian-Gang Li, Li-Qiang Xie, Jia-Wei Yan, Bing-Wei Mao

Journal of Electrochemistry

Potential-dependent structures of Pt(100)/ionic liquid 1-methyl-3-octylimidazolium hexafluorophosphate (OMIPF₆) interface have been studied by electrochemical scanning tunneling microscopy (ECSTM). The cation OMI⁺ forms ordered structure on Pt(100) surface, which exists in a potential region of about 1.2 V. When the potential is more negative than -0.6 V, it can be seen that the ordered structure transforms to disordered structure. When the potential shifts positively to +0.6 V, the desorption of cations OMI⁺ occurs, which indicates that strong electrostatic repulsion is needed to overcome chemical interaction between OMIPF6 and Pt(100) surface, leading to the desorption. The above results …

Lithium-Sulfur (Selenium) Batteries: Interface Issues And Solving Strategies, Nian-Wu Li, Ya-Xia Yin, Yu-Guo Guo

Journal of Electrochemistry

The stable interface is still a challenge for lithium-sulfur (selenium) batteries because of the low conductivity of sulfur (selenium), dissolution of polysulfide (polyselenide), volume expansion of sulfur (selenium), and lithium dendrite growth. This review describers some recent developments in lithium-sulfur (selenium) batteries and highlights our efforts in this field. The possible strategies for building stable interface in the lithium-sulfur (selenium) batteries including nano-restriction effect, chemical bonding, interface adsorption, surface coating, electrolyte optimization, and Lithium anode treatment have been discussed.

Stm Investigation Of Oxygen Reduction Reaction On Solid Interface In Fuel Cell, Zhen-Feng Cai, Bing Sun, Wen-Jie Jiang, Ting Chen, Dong Wang, Li-Jun Wan

Journal of Electrochemistry

An electrocatalyst for oxygen reduction reaction (ORR) is an important component for fuel cells. An investigation at interfacial electrochemical reactions toward ORR at a molecular scale benefits mechanistic understanding as well as rational design of catalysts. Scanning tunneling microscopy (STM) has been proven to be a powerful tool to monitor chemical reactions and to provide in-situ information about the interfacial electrochemical reactions at a molecular level. This review summarizes the recent STM studies in monitoring the interface processes such as morphological changes, molecular changes, reaction intermediates, and oxidation products. The prospects of future development in this field are outlined.

Syntheses Of Ag@Pd@Pt Nanoparticles With Tunable Shell Thickness For Electrochemical Oxidation Of Formic Acid, Xiao-Dong Lin, Du-Hong Chen, Zhong-Qun Tian

Journal of Electrochemistry

In an effort to lower cost of a catalyst, the silver (Ag) core with palladium (Pd) layer then platinum (Pt) island (Ag@Pd@Pt) nanoparticles were synthesized and the electrocatalytic activity of Ag@Pd@Pt nanoparticles on formic acid was compared with that of Au@Pd@Pt nanoparticles reported previously. The results showed that the existence of a small amount of Pt could significantly improve the activity of the catalyst. When the surface coverage of Pt approached 0.5 monolayers, the activity of Ag@Pd@Pt nanoparticles reached the maximum. Though the onset potential of the electro-oxidation was slightly more positive (about 50 mV), the overall electrocatalytic activity of …

Synthesis Of Ultrathin Co3O4 Nanoflakes Film Material For Electrochemical Sensing, Hui-Juan Wang

Journal of Electrochemistry

Ultrathin cobalt oxide (Co₃O₄) nanoflakes film material was synthesized by using an electro-deposited cobalt layer as a raw material through a simple oxidation method and followed by a heat treatment at 350 ^oC. The physical characterizations of the Co₃O₄ nanoflakes film were performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) technologies, and the electrochemical activity was measured by cyclic voltammetry (CV). As a promising material for electrochemical sensing, the as-synthesized ultrathin Co₃O₄ nanoflakes film material exhibited excellent electrochemical activity for H₂O …

Template-Assisted Hydrothermal Synthesis Of Nio@Co3O4 Hollow Spheres With Hierarchical Porous Surfaces For Supercapacitor Applications, Wen Zhou, Xue-Feng Lu, Ming-Mei Wu, Gao-Ren Li

Journal of Electrochemistry

Hollow structures have shown great potentials in a variety of important applications, such as energy conversion and storage. In order to further enhance the performance, the rational design of hollow structures with higher complexity in terms of composition and structure is highly desirable and still remains a great challenge. In this work, an efficient strategy was established for the fabrication of novel NiO@Co₃O₄ hollow spheres (HSs) with hierarchical porous surfaces by silica spheres template-assisted hydrothermal synthesis. The as-fabricated NiO@Co₃O₄ HSs showed high specific surface area of 219.68 m²·g^-1, and significant …

Micro/Nano-Structured Electrode Materials For Sodium-Ion Batteries, Shuang Yuan, Yun-Hai Zhu, Sai Wang, Tao Sun, Xin-Bo Zhang, Qiang Wang

Journal of Electrochemistry

Sodium has similar physics and chemical properties to lithium, alternatively, sodium (Na)-ion batteries have again aroused a great deal of interest recently, particularly for large-scale stationary energy storage applications due to the practically infinite sodium resources and low cost. However, the technics and materials for Na-ion batteries are immature. Therefore, development of advanced anode and cathode materials for Na-ion batteries is urgently desired but remains a great challenge. This paper briefly reviews some recent progresses in this field, addressing the morphology effects, as well as functions of carbon composite materials toward Na-ion batteries. Several electrode materials with micro/nano-structures based on …

The Study Of Dynamical Electrochemical Impedance Spectroscopy For Oxygen Reduction Reaction On Pt/C Catalyst, Kun-Ming Shi, Jian-Wei Guo, Jia Wang

Journal of Electrochemistry

With joint techniques of rotating disc electrode(RDE) and electrochemical impedance spectroscopy(EIS), and further establishment on equivalent circuit model, this paper studied oxygen reduction reaction(ORR) on commercial Pt/C catalyst in acid medium. Our results found that the dynamical interface on Pt/C consists of two independent processes: 1) the PtO reduction from Pt surface, 2) the new PtO formation from ORR, thus providing key clues for catalyst stability and activity. This also implied that the dynamical interface facilitates reconstruction for porous electrode, and matches with mass transfer. One important issue is discovered that at high overpotential, the high reaction rate for ORR …