Semiconductor and Optical Materials Commons^™

Design And Fabrication Of Nanostructured Electrodes For Complementary Electrochemical And Photoelectrochemical Water Splitting, Kholoud El Sayed Abousalem

Theses and Dissertations

Designing highly active, durable, and nonprecious electrodes for overall water splitting is of urgent scientific importance to realize sustainable hydrogen production. Accordingly, the need to search efficient energy production systems is of crucial necessity. In this thesis, two various systems for sustainable hydrogen production have been reported using electrochemical and photoelectrochemical pathways. In the first part of the thesis, electrochemical water splitting involving both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been established. To this end, an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn, Ni, Co phosphide catalysts directly on nickel foam via …

Engineering The Surface Of Fe3o4 Nanoparticles For Catalytic And Magnetic Applications, Natalia Da Silva Moura

LSU Doctoral Dissertations

With the rapid depletion of the U.S. energy resources coupled with population growth, heat management technologies must be improved to sustain our quality of life. Precisely, in catalysis, it is estimated that only ~50% of the energy supplied to the reactor is used for product conversion due to dissipation losses. Among the emerging technologies with a promising reduction in heat losses is induction heating, offering targeted heat delivery with magnetic nanoparticles. Under alternating magnetic fields (AMF), these nanoparticles can absorb the energy from Radio-Frequency (RF) fields and dissipate it as heat on the nanoparticle surface. This in situ heat generation …

Assessment Of Heavy Metal Concentration In Soils Around Geita The Gold Mine, Tanzania, Mariam G. Mgendi, Mkabwa L. K Manoko, W.J.S. Mwegoha, C. Southway C. Southway

Journal of Humanities and Social Sciences

Health issues related to gold mining cannot be underestimated. Gold mining produce acid mine drainage (AMD), which in turn releases heavy metals into the nearby environment, hence causing environmental pollution. Heavy metals are naturally very toxic, thus pose a great health concern especially when their concentration exceeds the recommended permissible limits. In this study, concentrations of five heavy metals—including Pb, Ni, Cr, Cu and Zn—were assessed in the soil around Geita Gold Mine (GGM). A total of 17 sampling sites were established from which the soil samples were collected at 0-15cm and 15-30cm soil depth. The concentration of both total …

Structure, Morphology And Composition-Property Elucidation Of Ni–Mo And Ni−Mo−P Nanocrystals For Water Splitting Reactions And Group Iv Alloy And Silicate Nanocrystals For Visible To Near Ir Optoelectronics, Ebtesam Hassan Abuelenein Eladgham

Theses and Dissertations

Abstract

Structure, Morphology and Composition-Property Elucidation of Ni–Mo and Ni−Mo−P Nanocrystals for Water Splitting Reactions and Group IV Alloy and Silicate Nanocrystals for Visible to Near IR Optoelectronics

by

Ebtesam Hassan Abuelenein Eladgham

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Advisor: Indika U Arachchige

Associate Professor, Department of Chemistry

Nanomaterials have gained a great attention because of their unique physical properties with size intermediate between molecular materials and extended solids. They have a large surface to volume ratio and display size tunable physical properties that was not …

Nanoflower-Like Bi2moo6/Ag3po4 In Water Treatment, Xavier Morgan-Lange, Jaeyun Moon, Kaleab Ayalew

McNair Poster Presentations

• Environmental issues continue to intensify causing natural resources such as clean water to become increasingly scarce while demand only continues to grow. • Some of the most effective measures taken appear to be bioremediation tactics and their synthetic counterparts. • A critical area of interest are semi-conducting photocatalytic nanomaterials that take advantage of the photo-electric effect and use the introduction of ultra violet (UV) and visible light to induce oxidation and reduction reaction in p-type semiconductors. This results in the decomposition of certain pollutants and/or deactivates certain microbes in water. • These materials have the potential to operate using …

Photocatalytic Mineralization Of Phenol On Fluidized Titanium Oxide-Coated Silica Gel, Guillermo J. Rincon

LSU New Orleans Theses and Dissertations

A bench-scale tubular reactor with recirculation was built in order to study the efficiency of the photocatalytic oxidation of phenol on fluidized titanium oxide-coated silica gel beads. A UV-C lamp placed along the central vertical axes of the reactor was used as source of photons. A bed of silica gel beads was fluidized by means of fluid recirculation and forced to follow upward helical flow around the lamp. Anatase was successfully synthetized on silica gel particles of average diameters 224, 357 and 461 µm, as confirmed by scanning electron micrographs, through a sol-gel technique using a titanium (iv)isopropoxide / hydrochloric …

Kinetic Study Of Photoelectrochemical Oxidation Of Lignin Model Compounds On Tio2 Nanotubes, Min Tian, Daniel Liba, Aicheng Chen

Journal of Electrochemistry

In this study, TiO₂ nanotubes were prepared via the electrochemical oxidation of titanium substrates in a non-aqueous electrolyte and their morphology and microstructures were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photoelectrochemical oxidation of two lignin model compounds, 1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanediol (DMP) and 3-hydroxy-1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanone (HDM), was investigated. A new band appeared at ~304 nm during the photoelectrochemical oxidation of DMP. The rate of DMP intermediate formation was amplified with the increase of initial concentrations, while it was diminished with increased temperature. Despite the similarity in structure between HDM and DMP, there are only small increases in absorbance …

The Investigations Of Surface Treatment Methods And Characterization Of Oxide Films On Ab5 Based Metal Hydride Electrodes Ⅰ. New NiRich Treatment Methods And Photoelectrochemical Characterization Of Oxide Films, Junmin Nan, Yong Yang, Jun Li, Zugeng Lin

Journal of Electrochemistry

Two simple and efficient surface treatment methods for AB₅ type hydrogen storage alloys were developed. The results of X-ray photoelectron spectroscopy (XPS) and cyclic voltammetric (CV) experiments showed that the hydrogen storage alloys treated by two different methods had Ni rich surface layer so that the performances of the electrodes were improved after treatment. The characterization of the oxide films which formed on the surface of electrodes through potentiodynamic oxidation with the help of photoelectrochemical microscopy (PEM) were done. The anodic photocurrent and the cathodic photocurrent related to the oxidation of hydrogen and the reduction of oxygen on the …

The Reduction Of Oxygen To Hydrogen Peroxide In An Acidic Trickle Bed Cell Using Graphite Chip Cathode, Zhaoe Lu, Guanyong Zhang, Tiangeng Zhong, Guonu Fang

Journal of Electrochemistry

The authors investigated the electrochemical reduction of oxygen to hydrogen peroxide in 0.05 mol/L H₂SO₄ solution by the trickle bed electrode using graphite chip. The bed dimension was 14×5×0.6 cm. The current efficiency and the concentration of H₂O₂ in the catholyte were determined at various current strengths and various rates of adding the electrolyte. The proper current was 0.15 A. i.e. the current density was 2.1 mA/cm² vertical cross section area of the bed. The concentration of H₂O₂ reached 7×10^-3 mol/L with the current efficiency of 0.2. If the …

Photoelectrochemical And Spectroelectrochemical Studies Oniron Oxide Ultrafine Particles, Maizhi Yang, Yongjun Ji, Wen Zhang, Shengmin Cai, Xiaojiang Lu, Zhongqun Tian, Jin Luo

Journal of Electrochemistry

In this paper, Raman spectra, photocurrent and the UV-VIS reflectance aremeasured for studying the α-Fe₂O₃ ultrafine particles adsorbed on Pt electrode. The blue shifts of Raman peaks demonstrate the size quantization effect for the particles of 50 nm in diameter ascompared with the bulk material. With the changing of the potential, the photocurrent decrcases as the UV-VIS reflectance increases, and vice-versa. Therefore, the potential not only affects the hargetransfer direcdtion in the interface of electrode/redox couple, but also influences the light absortion onthe surface of particles. According to the results of photoelectrochemistry, we suggest that the cathodic …

A Photoelectrochemical Investigation Of Zirconium Oxide Film, Maizhi Yang, Ping Wei, Di Quarto F., Piazza S., Sunseri C.

Journal of Electrochemistry

A photoelectrochemical investigation has been carried out on zirconium initialoxide film and its oxide film grownanodically at constant rate up to different thickness. Both anodicand cathedic photocurrents on the photocurrent spectrum depended on the potential, but had littlerelation with the forming anedic films or measuring solutions. Photocurrent spectrum and photocurrenttransients suggested that the oxide films on zirconium were duplex layers structure. The internal layerwas ZrO₂ and the external layer ZrO₂·(H₂O)_n. The photocurrent included photogenerated carrier ininternal and external oxide films, as well as internal photoinjection process for electrons from thesubstrate metal into the …