Chemistry Commons^™

Preparation Of Modified Titanium Based Pbo2 Electrode And Its Rapid Detection Of Cod, Qi Sun, Yan-He Han, Xiao-Lu Fu

Journal of Electrochemistry

In the traditional Ti/β-PbO₂ electrode, the crystal lattice difference between β-PbO₂ and Ti matrix is large, and the prepared electrode is easy to fall off and has a short service life. It needs to be modified in actual use. Based on the advantages of α-PbO₂ material and Ag material in terms of adhesion and conductivity, respectively, the above two materials are selected as the intermediate layer of Ti/β-PbO₂ electrode to improve electrode performance. In this paper, by preparing Ti/α/β-PbO₂ and Ti/Ag/β-PbO₂ electrodes …

Fundamentals Of Electrochemical Impedance Spectroscopy For Macrohomogeneous Porous Electrodes, Xiang Li, Qiu-An Huang, Wei-Heng Li, Yu-Xuan Bai, Jia Wang, Yang Liu, Yu-Feng Zhao, Juan Wang, Jiu-Jun Zhang

Journal of Electrochemistry

Electrochemical impedance spectroscopy (EIS) can be used to diagnose charge transfer reactions and mass transport in porous electrodes. The charge transfer reactions include interfacial charge accumulation and charge conduction as well as electrochemical reaction. In this paper, the complex phasor method is developed under the macrohomogeneous assumption to build an impedance model of porous electrodes for clarifying several vague expressions in the traditional approaches. The following researches are carried out: (1) Identifying characteristic parameters for the porous electrodes, including electrode electronic conductivity σ₁, electrolyte ionic conductivity σ₂, interface charge transfer conductivity g_ct, unit area …

Application Of Ti/Ruo2-Iro2-Sno2-Sb2O5 Anode In Rural Drinking Water Disinfection, Jing-Ru Guo, Xue-Jiao Zhang, Shuai Liao, Xue-Ming Chen

Journal of Electrochemistry

Sodium hypochlorite disinfection has many advantages, including reliable operation, low cost, easily available raw materials. It is, therefore, suitable for disinfection of drinking water in remote rural areas. The service life and chlorine evolution efficiency of the anode are the main factors restricting the performance of the sodium hypochlorite generator. The special conditions of frequent shutdown and low electrolyte concentration in the rural drinking water application also put forward high requirements on the performance of the anode. In this study, Ti/RuO₂-IrO₂-SnO₂-Sb₂O₅,a new-type and efficient chlorine evolution anode, was prepared by …

National Chemistry Week: From Irl To The Web, Ilayda Kelley, Daniela Mesa Sanchez

Purdue Journal of Service-Learning and International Engagement

National Chemistry Week, an outreach program initiated by the American Chemical Society (ACS), encourages scientists to bring their love of chemistry to their community. Celebrated nationwide, ACS invites businesses, schools, and individuals to organize and participate in community events to promote the value of chemistry in everyday life. The Purdue graduate student chapter of Iota Sigma Pi, a national honor society for women in chemistry, annually organizes one such celebration. On a normal year, this event is a large logistical undertaking in which 100+ volunteers go directly to over 70 local elementary school classrooms and perform a series of activities …

Developing Covalent-Organic Frameworks For Protecting Against Radiation, Megan J. Francis

Senior Theses

This research focuses on the development of lightweight, thermostable dual-function materials for secondary radiation protection and sensing by the integration of hydrogen-rich aliphatic chains inside the porous matrix of covalent-organic frameworks (COFs). The main aims of this project are the synthesis of organic linkers for forming a robust porous COF, synthesizing the porous COF through a condensation reaction, the development of hydrogen-rich aliphatic chains, and integration of aliphatic chains into COFs through click chemistry. This manuscript outlines the methodology and development of a novel self-assembled crystalline, porous material engineered to combine the functions of a shield and sensitive dosimeter. The …

Hemoglobin-Modified Core–Shell Fe3o4@Au Nanostructures For The Electrochemical Detection Of Acrylamide, Endang Saepudin, Tri Yuliani, Mochammad Arfin Fardiansyah Nasution, Munawar Khalil, Jong Wook Hong, Tribidasari Anggraningrum Ivandini

Makara Journal of Science

In this study, electrochemical detection of acrylamide using hemoglobin (Hb)-modified core–shell Fe₃O₄@Au nanostructures was conducted. Fe₃O₄ nanoparticles (~4.9 nm) and core–shell Fe₃O₄@Au (5.0–6.4 nm) nanostructures were successfully synthesized by the thermal decomposition method. Electrochemical investigation revealed that the optimum amount of Hb of 2 mg/mL could be immobilized in 0.1 M acetate buffer solution (pH = 6). Moreover, the detection of acrylamide using Fe₃O₄@Au/Hb was evaluated by the cyclic voltammetry technique. A linear calibration curve (R² = 0.98) in the concentration range of …

Effects Of Different Extraction Solvents On The Extractive Removal And Properties Of Oil Palm Empty-Fruit Bunch Cellulosic Nanofibers, Achmad Solikhin, Yusuf Sudo Hadi, Muh Yusram Massijaya, Siti Nikmatin

Makara Journal of Science

In this study, the effect of different extraction solvents on the isolation and properties of cellulosic nanofibers (CNFs) were investigated. The unextracted and different solvent-extracted CNFs formed horn-like features and irregularly aggregated nanofibers after oven drying. Scanning electron microscopy at 10000× magnification revealed the smooth external surfaces of all extracted CNFs; this finding is attributed to the limited deposition of amorphous lignocellulosic components on the fibers. All resultant CNF solutions revealed aggregation, with a particle size distribution and zeta average of 21.39–513.00 nm and 162.26–342.13 nm, respectively. Extraction with different solvents and chemical treatment yielded CNF solutions with good transparency. …

Controlling Degradation With Force And Light, Brad Davis

Dissertations

Stimuli-responsive polymers respond to changes in their environment by altering their physical and chemical properties. Their responsiveness allows them to be used as sensors, mechanical actuators, delivery systems, and can yield either elongated lifetimes through healing mechanisms or shortened lifetimes through triggered degradation. Still a growing field in polymer science, researchers seek to expand the capabilities of these materials by improving their specificity, range, and mechanisms of both the stimuli and the response. The work presented explores stimuli-responsive materials, focusing on mechanical and light stimuli, and how to gain control of the response by specific changes in the polymeric material. …

Two-Dimensional Monolayer Salt Nanostructures Can Spontaneously Aggregate Rather Than Dissolve In Dilute Aqueous Solutions, Wenhui Zhao, Yunxiang Sun, Weiduo Zhu, Jian Jiang, Xiaorong Zhao, Dongdong Lin, Wenwu Xu, Xiangmei Duan, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

It is well known that NaCl salt crystals can easily dissolve in dilute aqueous solutions at room temperature. Herein, we reported the first computational evidence of a novel salt nucleation behavior at room temperature, i.e., the spontaneous formation of two-dimensional (2D) alkali chloride crystalline/non-crystalline nanostructures in dilute aqueous solution under nanoscale confinement. Microsecond-scale classical molecular dynamics (MD) simulations showed that NaCl or LiCl, initially fully dissolved in confined water, can spontaneously nucleate into 2D monolayer nanostructures with either ordered or disordered morphologies. Notably, the NaCl nanostructures exhibited a 2D crystalline square-unit pattern, whereas the LiCl nanostructures adopted non-crystalline 2D hexagonal …

Enhanced Platinum (Ii) Drug Delivery For Anti-Cancer Therapy, Marek T. Wlodarczyk

Dissertations, Theses, and Capstone Projects

Over the years, anti-cancer therapies have improved the overall survival rate of patients. Nevertheless, the traditional free drug therapies still suffer from side effects and systemic toxicity, resulting in low drug dosages in the clinic. This often leads to suboptimal drug concentrations reaching cancer cells, contributing to treatment failure and drug resistance. Among available anti-cancer therapies, metallodrugs are of great interest. Platinum (II)-based agents are highly potent and are used to treat many cancers, including ovarian cancer (OC). Cisplatin (cis-diaminedichloroplatinum (II)) is the first Food and Drug Administration (FDA)-approved metallodrug for treatment of solid tumors, and its mechanism …

Molecular Dynamics Simulations Of Self-Assemblies In Nature And Nanotechnology, Phu Khanh Tang

Dissertations, Theses, and Capstone Projects

Nature usually divides complex systems into smaller building blocks specializing in a few tasks since one entity cannot achieve everything. Therefore, self-assembly is a robust tool exploited by Nature to build hierarchical systems that accomplish unique functions. The cell membrane distinguishes itself as an example of Nature’s self-assembly, defining and protecting the cell. By mimicking Nature’s designs using synthetically designed self-assemblies, researchers with advanced nanotechnological comprehension can manipulate these synthetic self-assemblies to improve many aspects of modern medicine and materials science. Understanding the competing underlying molecular interactions in self-assembly is always of interest to the academic scientific community and industry. …

Tools And Strategies For The Patterning Of Bioactive Molecules And Macromolecules, Daniel J. Valles

Dissertations, Theses, and Capstone Projects

Hypersurface Photolithography (HP) is a printing method for fabricating structures and patterns composed of soft materials bound to solid surfaces and with ~1 micrometer resolution in the x, y, and z dimensions. This platform leverages benign, low intensity light to perform photochemical surface reactions with spatial and temporal control of irradiation, and, as a result, is particularly useful for patterning delicate organic and biological material. In particular, surface- initiated controlled radical polymerizations can be leveraged to create arbitrary polymer and block- copolymer brush patterns. Chapter 1 will review the advances in instrumentation architectures from our group that have made these …

Synthesis, Characterization And Applications Of Europium Based Perovskite Oxide Nanoparticles, Nasim Farahmand

Dissertations, Theses, and Capstone Projects

The synthesis and characterization of nanocrystalline transition and rare-earth metal oxides have been studied widely over the past years. These materials possess unique physical, chemical, magnetic and dielectric properties which make them potential candidates for a wide range of applications such as electronics, energy storage and photocatalysis. There are a number of synthesis methods for preparing these materials, where most of them require stringent conditions such as high pressure and high temperature. However, in this study, a modified sol-gel synthesis has been used with a lower calcination temperature to make uniform nanocrystals of the transition/rare-earth metal oxide family. The focus …

Modeling Vitexin And Isovitexin Flavones As Corrosion Inhibitors For Aluminium Metal, Abdullahi Muhammad Ayuba, Umaru Umar

Karbala International Journal of Modern Science

Theoretically, the aluminium corrosion inhibitive performance of vitexin (VTX) and isovitexin (SVT) were evaluated with a view of establishing the mechanism of the inhibition process. Calculations which include the consideration of several global descriptors were studied to describe and correlate the reactivity of the molecules with the computed descriptors. First and second-order condensed Fukui functions were employed to analyze local reactivity parameters, while simulations involving the adsorbed molecules on Al (1 1 0) surface were conducted through quench dynamic simulations and the mechanism of physical adsorption was established with SVT relatively been a better inhibitor on Al surface than VTX.

High Speed Impact On Graphene Composites, Giovanny A. Espitia

Symposium of Student Scholars

Since the isolation of Graphene occurred in 2004, numerous studies attempting to exploit the properties of this carbon allotrope have been conducted. Graphene exists in a 2-D manner with sp2 bonds, which provides the allotrope with great electrical, conductive, and mechanical properties. In this paper however, we will focus on the latter in order to examine the feasibility of graphene composites for bulletproof material in the military. Pure graphene sheets count with high porosity density that leads to structural defects as well as poor mechanical properties due to physical contact being sole retainer. For this reason, the selected composite is …

Activated Carbon Pore Expansion Using Acidic Hydrothermal Method, Max Thompson

Symposium of Student Scholars

Petroleum Coke is a widely abundant, high carbon content material produced as a byproduct of the oil refining process. Its abundance makes the price per ton low and it is produced in almost all regions of the world. Due to the low price and high carbon percentage, commercial companies make large amounts of activated carbon using petroleum coke as a precursor. These activated carbons are characterized by their high surface area and can achieve widely varying pore morphology with different activation processes. The goal of this work is to achieve a homologous mesopore activated carbon material for use in super …

Solid-State Redox Synthesis Of Layered Birnessite-Type Manganese Dioxide (Δ-Mno2) As Aqueous Supercapacitor Electrodes, Armando Rodriguez Campos

Symposium of Student Scholars

Nanostructured manganese dioxides are attractive cathode materials in aqueous supercapacitors due to their low cost, environmental benign nature, high theoretical gravimetric capacitance, and power in neutral aqueous electrolytes. In this work, a layered birnessite-type manganese dioxide (δ-MnO₂) is synthesized utilizing solid-state redox method with superoxide. The effects of temperature and oxidant amount on the physicochemical properties of δ-MnO₂ are characterized using Elemental Dispersion X-ray (EDX) spectroscopy, X-ray diffraction (XRD), N₂-sorption, and Scanning Electron Microscope (SEM). The physiochemical properties that are specifically analyzed by varying synthesis conditions pertain to the chemical composition, morphology, and surface area …

Dft Study Of NiM@Pt1AuN-M-1 (N=19, 38, 55, 79; M = 1, 6, 13, 19) Core-Shell Orr Catalyst, Wen-Jie Li, Dong-Xu Tian, Hong Du, Xi-Qiang Yan

Journal of Electrochemistry

The slow kinetics of oxygen reduction reaction (ORR) limits the performance of low temperature fuel cells. Thus, it needs to design effective catalysts with low cost. Core-shell clusters (CSNCs) show promising activity because of their size-dependent geometric and electronic effects. The ORR activity trend of Ni_m@Pt₁Au_n-m-1(n = 19, 38, 55, 79; m = 1, 6, 13, 19) was studied using the GGA-PBE-PAW methods. The adsorption configurations of *O, *OH and *OOH were optimized and the reaction free energies of four proton electron (H⁺ + e^-) transfer steps …

One-Pot Synthesis Of Fe2O3@Fe-N-C Oxygen Reduction Electrocatalyst And Its Performance For Zinc-Air Battery, Hua Lin, Yi-Jin Wu, Jun-Tao Li, Yao Zhou

Journal of Electrochemistry

Oxygen reduction reaction (ORR) plays a profound role in determining cathode performance in metal-air batteries and fuel cells. Owing to its inherently sluggish kinetics, high-performance ORR catalysts which favors the scissoring of O-O bond and formation of O-H bond are a requisite. In this regard, Pt has been explored as the most efficient ORR electrocatalysts. Nevertheless, due to its expensiveness, the usage of Pt catalysts represents one of the major sources of cost in those energy conversion devices. Thus, the development of alternative ORR electrocatalysts with minimized Pt utilization has been widely pursued over the past few decades. Metal-nitrogen-carbon catalysts …

Study On Mxene-Carbon Black/Sulfur Composite In Integrated Electrode Of Lithium-Sulfur Batteries, Ye-Peng Fan, Ye-Qiang Luo, Pei-Kang Shen

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries are considered as a promising energy storage device due to their ultrahigh theoretical energy density of 2500 Wh·kg^-1 and low cost. However, the practical application of Li-S batteries is seriously limited by their low actual energy density, the shuttle effect of polysulfides (LiPSs), and the insulating nature of sulfur and lithium sulfides. Carbon materials have been developed in the design of sulfur hosts due to their adjustable pore structure and high electrical conductivity, but their non-polar surfaces have weak interactions with LiPSs. Herein, MXene-carbon black/sulfur (Ti₃C₂T_x-CB/S) composites were prepared and …

Preparation Of 3d Semi-Interpenetrated Polymer Networks Polymer Electrolyte For Lithium Metal Battery, Yun-Feng Zhang, Jia-Ying Wang, Xiao-Jie Li, Shi-Yu Zhao, Yang He, Shi-Kang Huo, Ya-Ying Wang, Chang Tan

Journal of Electrochemistry

As the next generation high-energy batteries, lithium metal battery has attracted more and more attention due to its highest specific capacity (3860 mA·h·g^-1) and the lowest anode potential (-3.04 V versus the standard hydrogen electrode, SHE). However, the safety problem caused by lithium dendrite growth is one of the biggest challenges for the commercialization of lithium metal batteries. Single ion conducting polymer electrolytes, which deliver high lithium ion transference number, represent one of the important strategies to inhibit lithium dendrite growth. However, the poor compatibility with electrodes and low ionic conductivity largely limit their practical application. In the …

Preparation And Electrochemical Evaluation Of Mos2/Graphene Quantum Dots As A Catalyst For Hydrogen Evolution In Microbial Electrolysis Cell, Hong-Yan Dai, Hui-Min Yang, Xian Liu, Xiu-Li Song, Zhen-Hai Liang

Journal of Electrochemistry

Microbial electrolysis cell (MEC) is a relatively new bioelectrochemical technology that produces H₂ and meanwhile treats organic wastewater. Cathode hydrogen evolution catalyst plays a key role in MEC. The doping of Graphene Quantum Dots (GQDs) into MoS₂ nanosheets can improve the catalytic activity of MoS₂ by creating abundant defect sites both in the edge plane and the basal plane, as well as enhancing the electrical conductivity. In this paper, using Na₂MoO₄ , cysteine and GQDs as raw materials, a series of MoS₂/GQDs composites were firstly synthesized via hydrothermal method, and then loaded …

Study On Inhibition Of Lithium Dendrite Growth By Mg(No3)2 Additive In Carbonate Electrolyte, Biao Zhang, Yi Shuai, Yu Wang, Na-Chuan Yang, Kang-Hua Chen

Journal of Electrochemistry

In the lithium-sulfurized polyacrylonitrile battery system, the formation and growth of lithium dendrites in the negative electrode seriously deteriorate the charge and discharge performance of the battery. If the growth of lithium dendrites pierces the separator and causes thermal runaway, it will also bring serious damage to the battery, causing potential safety risks. In the carbonate electrolyte that is more conducive to stabilizing the positive electrode sulfurized polyacrylonitrile material, the growth of lithium dendrites is particularly serious. In this paper, magnesium nitrate was added to the carbonate electrolyte to investigate the combined effect of nitrate and magnesium ions on the …

A Comparison In Structural Transformation Of Li[NiXCoYMnZ]O2 (X = 0.6, 0.85) Cathode Materials In Lithium-Ion Batteries, Li-Juan Li, Zhen-Dong Zhu, Juan Dai, Rong-Rong Wang, Wen Peng

Journal of Electrochemistry

In this paper, the phase transformation voltage ranges of two layered oxide ternary cathode materials, namely, Li(Ni_0.85Co_0.10Mn_0.05)O₂ (referred to Ni85, presenting high Ni content) and Li(Ni_0.6Co_0.2Mn_0.2)O₂ (referred to Ni60, presenting common low Ni content), were classified and determined. The structural differences between high Ni and common low Ni ternary materials were studied in order to understand the structure instability of high nickel material during the charging process. At the same time, the differential capacity (dQ·dV^-1) curves of Ni85 and Ni60 positive …

A Preliminary Study On Graphene Film-Metal Composites Prepared By Electrodeposition, Shuang-Juan Liu, Hai-Jing Wang, Jing Guo, Peng-Cheng Wang, Hao Zhou, Cai Meng, Han-Jie Guo

Journal of Electrochemistry

Graphene film (GF) has excellent electrical and thermal conductivity, but low strength and hardness. In order to obtain good comprehensive mechanical properties to improve the practical value of GF, the concept of preparing GF-metal composite materials was proposed. This work was conducted to preliminarily study the feasibility of using electrodeposition method to prepare GF-metal composites. Two kinds of composites, GF-Cu and GF-Cr, were successfully prepared by using GF as the cathode, and pure Cu and DSA (Dimensionally Stable Anode) as the anodes, respectively, with applying DC power externally. Employing certain electrochemical parameters, the cation in the electrolyte moved towards the …

Effect Of Conductive Additives On Electrochemical Performance Of All-Solid-State Li-S Batteries, Dong-Hao Wang, He-Feng Yan, Zheng-Liang Gong

Journal of Electrochemistry

All-solid-state lithium sulfur batteries (ASSLSBs) with inorganic solid electrolytes offer an opportunity to realize both high energy density (lithium metal ~ 3860 mAh·g^-1, sulfur ~ 1675 mAh·g^-1), safety and reliability, via eliminating the polysulfides shuttle effect and flammable liquid electrolyte. However, it still remains a huge challenge for ASSLSBs to achieve high areal active mass loading, high utilization efficiency of the active materials and good cycle stability simultaneously due to the insulating nature of sulfur and Li₂S (conductivities of sulfur and Li₂S are 5×10^-30 S·cm^-1 and 3.6×10^-7 S·cm^{-1 …}

Preparation And Characterization Of Thermoplastic Polyurethane-Based Polymer Electrolyte, Li Zhou, Lie Wu, Zhao-Ming Xue

Journal of Electrochemistry

Electrolyte still has to be improved to satisfy the increasingly rigid demands of lithium ion batteries that have higher energy densities. Thermoplastic polyurethane (TPU) has two phase structures of soft segments and hard segments, which can guarantee the electrochemical and physical performances of electrolyte for lithium ion battery. It is now creatively applied to the gel polymer electrolyte matrix of lithium ion batteries. In this paper, a novel polymer membrane based on thermoplastic polyurethane/cellulose acetate (TPU/CA) was prepared by non-solvent induced phase separation (NIPS) method. Further, the TPU/CA blending gel polymer electrolyte (GPE) was prepared by absorbing liquid electrolyte. The …

Preparation Of Coo/Rgo@Ni Foam Electrode And Its Electrocatalytic Reduction Of Co2, Qian Guo, Jia-Long Fu, Cheng-Yan Zhang, Chao-Yue Cai, Cheng Wang, Li-Hua Zhou, Rui-Bo Xu, Ming-Yan Wang

Journal of Electrochemistry

The worldwide extensive release of carbon dioxide (CO₂) has caused serious environmental pollution and unprecedented climate change problems. Thus, for the sustainable development of human society, it is very necessary to convert CO₂ to renewable fuels through clean and economical processes. The electrochemical CO₂ reduction reaction (CO₂RR) is regarded as a promising approach for the recycling of carbon resource and the generation of sustainable fuels. However, the slow kinetics and formation of multiple products in CO₂RR hinder its large-scale application. Hence, great research efforts are made to develop electrocatalysts with high product …

Storage Performance And Mechanism Of Mose2 Nanospheres In Lithium And Magnesium Ion Batteries, Yi Peng, Wei Zhang, Fang-Zhen Zuo, Hao-Ying Lv, Kai-Jun Hong

Journal of Electrochemistry

Molybdenum diselenide (MoSe₂) is a two-dimensional (2D) transition metal dichalcogenide (TMD) material, attracting wide attention in lithium ion battery (LIB) and exhibiting great potential in next-generation magnesium ion battery (MIB) due to its unique layered structure with fast ion mobility and weak van der Waals interlayer interaction. However, the reported literatures related to MoSe₂ mainly focus on the enhancement of performance in LIB without deep storage mechanisms investigations. Meanwhile,the magnesium storage capacity and mechanisms have not been explored. In this work, MoSe₂ nanospheres were synthesized via wet chemical route and followed by annealing treatment. When used …

From Small Molecules To Infinite Crystals: Probing Noncovalent Interactions Through Vibrational Spectroscopy, Sadisha Nanayakkara

Chemistry Theses and Dissertations

During my four years in the CATCO group supervised by Dr. Kraka, I have been exposed to various topics targeted to address a multitude of chemical problems, broadening our knowledge of modern chemistry research as we know it. In undertaking the age-old problem of understanding the nature of chemical bonding, I could modestly contribute with my work, using in-house tools based on vibrational spectroscopy.

First part of my dissertation is focused on inventing new methods and tools to efficiently investigate chemical bonding, followed by the study of some non-covalent interactions, imperative in catalysis and solid-state chemistry. This includes analysis of …