Chemistry Commons^™

Investigation Of The Thermodynamics For The Removal Of As(Iii) And As(V) From Water Using Synthesized Zno Nanoparticles And The Effects Of Ph, Temperature, And Time, Helia Magali Morales, Grecia Torreblanca, Arnulfo Mar, Mataz Alcoutlabi, Thomas Eubanks, Erik Plata, Jason Parsons

Chemistry Faculty Publications and Presentations

In the present study, the removal of both As(III) and As(V) from aqueous solutions using synthesized ZnO nanomaterials was achieved. The ZnO nanomaterial was synthesized using a precipitation technique and characterized using XRD, SEM, and Raman spectroscopy. XRD confirmed the ZnO nanoparticles were present in the hexagonal wurtzite structure. SEM of the particles showed they were aggregates of triangular and spherical particles. The average nanoparticle size was determined to be 62.03 ± 4.06 nm using Scherrer’s analysis of the three largest diffraction peaks. Raman spectroscopy of the ZnO nanoparticles showed only ZnO peaks, whereas the after-reaction samples indicated that As(V) …

Synchrotron Study Of Phase Transition And Heterostructures In Metal Oxide Semiconductors, Bingyu Dong

Electronic Thesis and Dissertation Repository

Transition metal oxides, including titanium dioxide (TiO₂), zinc oxide (ZnO) and Tin dioxide (SnO₂) are widely recognized semiconducting photocatalysts. This project engages in a detailed examination of the phase transition of TiO₂ and the synthesis of heterostructured metal oxides using an eco-friendly method of ball-milling. A variety of spectroscopy and microscopy techniques have been used to analyze the products. Synchrotron-based techniques: X-ray Absorption near-edge spectroscopy (XANES), X-ray Emission Spectroscopy and X-ray excited optical luminescence (XEOL) can demonstrate the local structure and bonding. The finding highlights a phase transition in TiO₂ and the formation of …

Quantum Mechanical Studies Of Water Splitting Reaction With (Zno)3 Nanoclusters As Catalysts, Duwage C. Perera

Electronic Theses and Dissertations

With the current energy crisis, H₂ production through the water-splitting reaction has drawn attention recently. In this thesis, I studied the structural (geometry) and electronic properties (vertical detachment energy and electron affinity) of ZnO monomers and dimers using density functional theory. ZnO is a metal oxide with a 3.37 eV band gap and can be a commercially cheaper photocatalyst in hydrogen (H₂) production. The B3LYP/DGDZVP2 pair was selected after investigating different pairs of exchange functionals and basis sets to study the hydration, hydrolysis, and water-splitting reaction. The singlet-triplet energy gaps of small (ZnO)_n clusters (n=1-6) of …

Catalytic Pyrolysis Of Olive Oil Residue To Produce Synthesis Gas: The Effect Of Bulk And Nano Metal Oxides, Ebru Karadağ, Selva Bi̇lge, Yusuf Osman Donar, Ali̇ Sinağ

Turkish Journal of Chemistry

In this study, olive oil residue (OR) biomass was pyrolyzed in the presence of bulk MgO (B-MgO), nano-MgO (N-MgO), bulk ZnO (B-ZnO)), and nano-ZnO (N- ZnO) metal oxides at different temperatures (400, 600, and 800 ºC). Significant results were obtained in terms of synthesis gas formation and CO2 reduction. The efficiency distribution of the products obtained as a result of the metal oxide-based pyrolysis process and the effects of metal oxides were examined in detail. Nanometal oxides were synthesized by the hydrothermal method. Characterization of metal oxides was carried out by Brunauer?Emmett?Teller (BET), x-ray powder diffraction (XRD) analysis and scanning-electron …

Application Of The Taguchi Approach To Optimize Zno Synthesis Via Hydrothermally Assisted Sol-Gel Method, Zahra Khaghanpour, Sanaz Naghibi

Turkish Journal of Chemistry

ZnO powder was synthesized via a hydrothermally assisted sol-gel method. Synthesis variables including Zn-precursor type, pH value, time, and temperature of hydrothermal treatment were analyzed using the Taguchi approach. The experimental procedures were defined based on the L9 array for four variables in three levels. The influences of those variables on the response parameters, i.e. crystallite size, crystallinity, band gap energy ($E_{g})$, and degradation constants ($k)$, were evaluated. XRD results and $E_{g}$ values showed that ZnO wurtzite appeared to be the only crystalline phase in the samples. Taguchi analysis predicted that the optimized conditions to achieve the highest photoactivity are …

Zno/Cdo Nanocomposites For Textile Effluent Degradation And Electrochemical Detection, Mohammad Mansoob Khan Dr

Dr. Mohammad Mansoob Khan

In this report, the photocatalytic and electrochemical activity of ZnO and ZnO/CdO nanocomposites were determined. Pure ZnO and nanocomposite ZnO/CdO were prepared by a vapor to solid mechanism and were characterized by different physical and chemical techniques. The CdO-modified ZnO possessed high efficiency to degrade textile effluent. It also showed high efficiency of degradation, such as 98% for methylene blue and 93% for methyl orange. Cadmium oxide (impurity) plays an important role in achieving zinc oxide materials that exhibit UV to visible light degradation of textile effluent. Additionally, uric acid sensing performed to study the electrochemical activity revealed that ZnO/CdO …

Fabrication And Electrochemical Properties Of Graphene-Zno Nanocomposite, Chuan-Ling Men, Wan Wang, Jun Cao

Journal of Electrochemistry

In this work, the graphene-ZnO nanocomposite was successfully synthesized through a one-step solvothermal approach, using ethylene glycol as the solvent and reducing agent. The ZnO particles could be attached to the surfaces and edges of graphene sheet. The electrochemical performance of the nanocomposite was investigated by performing cyclic voltammetry, A.C. impedance and chronopotentiometry tests in 6 mol·L^-1 KOH. The results showed that the graphene-ZnO nanocomposite exhibited a nice electrochemical specific capacitance of 115 F·g^-1 determined in cyclic voltammetry test, or 71 F·g^-1 evaluated in chronopotentiometry test and good reversible charge/discharge behavior.

Formation And Analysis Of Zinc Oxide Nanoparticles And Zinc Oxide Hexagonal Prisms And Optical Analysis Of Cadmium Selenide Nanoparticles, Jared M. Hancock

Theses and Dissertations

In this dissertation, methods to synthesize ZnO are reported. First, zinc oxide nanoparticles were synthesized with small amounts of transition metal ions to create materials called dilute magnetic semiconductors (DMS). We employed a low temperature sol-gel method that produces ZnO nanoparticles of reproducible size and incorporates cobalt, nickel, and manganese ions into the nanoparticles. Conditions were controlled such that a range of amounts of Co, Ni, and Mn were incorporated. The incorporation was tracked by color changes in the white ZnO powder to blue for Co, green for Ni and yellow for Mn. XRD measurements showed the nanoparticles were on …

Formation Mechanisms And Photocatalytic Properties Of Zno-Based Nanomaterials, Natalie Herring

Theses and Dissertations

Zinc Oxide (ZnO) is one of the most extensively studied semiconductors because of its unique properties, namely, its wide band gap (3.37 eV) and high excitation binding energy (60 meV). These properties make ZnO a promising material for uses in a broad range of applications including sensors, catalysis and optoelectronic devices. The presented research covers a broad spectrum of these interesting nanomaterials, from their synthesis and characterization to their use as photocatalyts. A new synthetic approach for producing morphology controlled ZnO nanostructures was developed using microwave irradiation (MWI). The rapid decomposition of zinc acetate in the presence of a mixture …

Novel Microwave Assisted Synthesis Of Zns Nanomaterials, Suresh Pillai, Michael Seery, Damian Synnott, John Colreavy, Stephen Hinder

Articles

A novel ambient pressure microwave-assisted technique is developed in which silver and indium modified ZnS is synthesised. The as prepared ZnS is characterised by X-ray diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and luminescence spectroscopy. This procedure produced crystalline materials with particle sizes below 10 nm. The synthesis technique leads to defects in the crystal which induce mid energy levels in the band gap and lead to indoor light photocatalytic activity. Increasing the amount of silver causes a phase transition from cubic blende to hexagonal phase ZnS. In a comparative study, when the ZnS cubic blende is heated in a conventional …

A Highly Efficient Tio2-Xcx Nano-Heterojunction Photocatalyst For Visible-Light Induced Antibacterial Applications, Vinodkumar Etacheri, Michael Seery, Stephen Hinder, Georg Michlits, Suresh Pillai

Articles

Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) non-hydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 minutes of microwave irradiation exhibits a 2-fold higher visible-light induced photocatalytic activity in contrast to the standard commercial photocatalyst Evonik-Degussa P-25. Staphylococcus aureus inactivation rate constant for carbon-doped nano-heterojunctions and the standard photocatalyst was 0.0023 and -0.0081 min …

Interaction Of Ceo2 And Zno Nanoparticles Towards The Symbiotic Association Of Alfalfa (Medicago Sativa) And Sinorhizobium Meliloti In Soil, Susmita Bandyopadhyay

Open Access Theses & Dissertations

The production of engineered nanoparticles (ENPs) has rapidly increased due to their wide range of applications in the field of electronics, medicine, chemistry and biology. Consequently, concerns have risen about the environmental release and potential negative impact of NPs. A few reports have described the effects of TiO2 NPs and quantum dots upon nitrogen fixing bacteria. However, the understanding of the interaction of NPs in plant-microbe interface (symbiotic association), like alfalfa (Medicago sativa L.)-Sinorhizobium meliloti, is still in its infancy. Alfalfa is the world's most important forage crop. It grows in association with S. meliloti, which is very important in …

Determination Of The Effects Of Zno And Ceo2 Nanoparticles In Mesquite (Prosopis Juliflora) And Soybean (Glycine Max): Synchrotron And Spectroscopic Approaches, Jose Angel Hernandez Viezcas

Open Access Theses & Dissertations

The rapid growth of nanotechnology is exposing the environment to abnormal concentrations of engineered nanoparticles (NPs). There is concern about the unknown consequences of NPs on the environment and human health. This Dissertation has relied significantly on Synchrotron and other spectroscopic techniques to give insights on the effects, speciation and distribution of two metal oxide nanoparticles (ZnO, CeO2) on two plant species (Mesquite and Soybean). We evaluated the effects of ZnO (10 nm) and CeO2 (8 nm) NPs on a plant species native to the semi-arid regions of North America, Mesquite (Prosopis juliflora velutina). Mesquite plants grown in hydroponic culture …

Adsorption Of Hydrogen Onto Bare And Metal Decorated Metal Oxides, Paige Elizabeth Landry

Doctoral Dissertations

Catalytically relevant metal clusters were deposited on metal oxide supports. Palladium and gold were deposited on mixed morphology ZnO, and palladium was deposited on MgO(100). The materials were characterized with electron microscopy, photoluminescent spectroscopy, and X-ray photoelectron spectroscopy. The behavior of hydrogen on these materials, as well as bare ZnO, was studied using volumetric isotherms. The isotherms were used to determine the monolayer gas coverage, surface

area, and heats of adsorption of hydrogen on these materials over the temperature range of approximately 8-13 K. At the temperatures and pressures studied, hydrogen physically adsorbed onto the materials. Additional investigations with inelastic …

Crystallisation And Phase Transition Characteristics Of Sol-Gel-Synthesized Zinc Titanates, Suresh Pillai, Michael Seery, Nicholas Nolan

Articles

No abstract provided.

A Novel Processing Route For The Production Of Nanoparticulate Zinc Oxide Using An Isophthalate Precursor, Grainne Duffy, Declan Mccormack, Suresh Pillai

Articles

Zinc oxide nanoparticles have been processed from a novel isophthalate precursor. In contrast to those processed from an oxalate precursor, this material exhibits three-dimensional, non-directional aggregation behaviour.

Such non-directional aggregation of uniaxial crystallites may allow for the production of structures with a higher proportion of catalytically active surfaces than can be prepared through conventional sol–gel methods. XRD,

FTIR, TEM and SEM were used to characterize the synthesized materials.

Zinc oxide particles synthesized by using isophthalic acid (C6H4-1,3-(COOH)2) are found to be slightly smaller than the previously reported materials prepared through chelation with oxalic acid (H2C2O2・2H2O).

Silver Doped Titanium Dioxide Nanomaterials For Enhanced Visible Light Photocatalysis, Michael Seery, Reena George, Suresh Pillai, Patrick Floris

Articles

This paper presents a systematic study on two different preparation methods for titanium dioxide with silver. The silver can be incorporated by irradiating the reaction mixture during preparation to reduce silver ion to silver metal or by direct calcination of the sol–gel material to decompose silver nitrate to silver. Of the two methods, we found the latter produces a more effective photocatalytic material (6–50% improvement in catalytic efficiency), which is attributed to the fact that the silver is homogeneously dispersed throughout the material. The efficiency of the materials were examined using a Q-Sun solar simulator (visible light) and in Dublin …

Stability And Electrochemical Performance Of Nio Cathode Modified By Zno Additive For Mcfc In Molten Carbonates, Huang Bo

Journal of Electrochemistry

The ZnO/Ni composite cathode was fabricated by tape-casting method, which microstructures and phases were studied. The electrochemical behaviors of ZnO impregnated NiO cathodes were also evaluated in molten 62 mol%Li_2CO_3+(38 mol%) K_2CO_3eutectic at 650 ℃ by electrochemical impedance spectroscopy (EIS) as a function of ZnO content and immersion time. The ZnO impregnated nickel cathodes showed the similar porosity, pore size and morphology to the reference nickel cathode. The stability tests of ZnO impregnated NiO cathodes showed that the ZnO additive could dramatically reduce the solubility of NiO in a eutectic carbonate mixture under the standard cathode gas condition. The cathode …