Physical Chemistry Commons^™

Effects Of Traps On Photo-Induced Interfacial Charge Transfer Of Ag-Tio2: Photoelectrochemical, Electrochemical And Spectroscopic Characterizations, Zhi-Hao Liang, Jia-Zheng Wang, Dan Wang, Jian-Zhang Zhou, De-Yin Wu

Journal of Electrochemistry

In the field of metal-semiconductor composites based plasmon-mediated chemical reactions, a clear and in-depth understanding of charge transfer and recombination mechanisms is crucial for improving plasmonic photocatalytic efficiency. However, the plasmonic photocatalytic reactions at the solid-liquid interface of the electrochemical systems involve complex processes with multiple elementary steps, multiple time scales, and multiple controlling factors. Herein, the combination of photoelectrochemical and electrochemical as well as spectroscopic characterizations has been successfully used to study the effects of traps on the photo-induced interfacial charge transfer of silver-titanium dioxide (Ag-TiO₂). The results show that the increase of surface hydroxyl groups may …

Pulse Electroplating Of Nanotwinned Copper Using Mps-Peg Two-Additive System For Damascene Via Filling Process, Yu-Xi Wang, Li-Yin Gao, Yong-Qiang Wan, Zhe Li, Zhi-Quan Liu

Journal of Electrochemistry

High density nanotwinned copper films were pulse electroplated using an optimized electrolyte. In order to find out the influencing factors on the formation of nanotwins, series contents of MPS were added to the electrolyte during the pulse electroplating process. It was found that the copper films electroplated without MPS had large grains but a few nanotwins. And the grain size was about 0.9 μm on average, and the texture components of (110) and (111) crystal orientations were calculated as 49% and 27.8%, respectively. Differently, when 10 ppm MPS was added, the microstructure was changed to columnar grain with high density …

Effect Of Amine Additives On Thermal Runaway Inhibition Of Sic||Ncm811 Batteries, Bo-Wen Hou, Long He, Xu-Ning Feng, Wei-Feng Zhang, Li Wang, Xiang-Ming He

Journal of Electrochemistry

The high energy density of NCM batteries with high nickel content is a key advantage in replacing fossil fuels and promoting clean energy development, at the same time, is also a fundamental cause of serious safety hazards in batteries. Primary and secondary amines can lead to ring-opening polymerization of common ethylene carbonate electrolytes, resulting in an isolation layer between the cathode and the anode, and improving the thermal safety of the battery. In this work, the safety of batteries is considered both at the material level and at the cell level, based on the chemical reactions between amines and the …

The Effect Of Hydrogen Peroxide On The Corrosion Dynamics Of Carbon Steel, Kwang Soak Gabriel O'Donnell

Electronic Thesis and Dissertation Repository

The Used Fuel Container (UFC) is a key barrier in Canada’s nuclear fuel disposal plan. Understanding the radiation-induced corrosion of the carbon steel (CS) vessel is critical for predicting the long-term integrity of the UFC. Developing a mechanistic understanding of CS corrosion and the effect of solution parameters is essential.

This work investigates the effects of H₂O₂, the key radiolytic oxidant, on CS corrosion dynamics in small, stagnant solutions. Elementary processes are identified, corrosion rates are calculated, and the effects of H₂O₂ concentration are investigated. Corrosion was studied by quantifying the concentrations of …

Dinitrogen Functionalization Using A Molybdenum Atom: Bridging The Gap Between Small And Coordination Complexes Via Quantum Mechanical Methods, Maria Virginia White

Doctoral Dissertations

Chemistry devotes a significant amount of its research to understanding small molecule activation from an electronic structure perspective to help with the investigation of the reaction pathways of catalytically active substances that can promote biomimetic catalysis. A large portion of the energy used annually in our planet is used for the artificial nitrogen fixation (Haber-Bosch process), which renders dinitrogen activation a subject of study. Molybdenum, a fourth row transitional metal, has demonstrated its effectiveness as an essential component of the dinitrogen reduction catalytic process. To better understand the multiple dinitrogen molybdenum binding modes, the work described herein combines wave function …

Theoretical Studies Of Adsorption And Reactivity At The Gas-Solid Interface, Carson J. Mize

Doctoral Dissertations

Catalytic transformations of small molecules is of great interest for both laboratory and industrial practices. Two specific transformations are ethylene to ethylene oxide and combinations of azides and alkenes into aziridine molecules. Ethylene oxide is an epoxide used as a feed-stock for many bulk reactions and commercial products such as antifreeze and various sterilization techniques, while molecules with the aziridine functional group are used for many ring opening and closing techniques as well as in pharmaceuticals and other drug treatments. For production of ethylene oxide, the combination of oxygen adsorbed onto a silver crystal is the known catalysts for thus …

Chirality, Symmetry-Breaking, And Chemical Substitution In Multiferroics, Kiman Park

Doctoral Dissertations

Multiferroic materials attract significant attention due to their potential utility in a broad range of device applications. The inclusion of heavy metal centers in these materials enhances their magnetoelectric properties, yielding fascinating physical phenomena such as the Dzyaloshinskii–Moriya interaction, nonreciprocal directional dichroism, enhancement of spin-phonon coupling, and spin-orbit-entangled ground states. This dissertation provides a comprehensive survey of magnetoelectric multiferroics containing heavy metal centers and explores spectroscopic techniques under extreme conditions. A microscopic examination of phase transitions, symmetry-breaking, and structure-property relationships enhances the fundamental understanding of coupling mechanisms.

In A2Mo3O8 (A = Fe, Zn, Ni, and Mn), we use optical spectroscopy …

Advances In One-Electron Self-Interaction-Correction Methods For Accurate And Efficient Self-Interaction-Free Density Functional Calculations, Selim Romero

Open Access Theses & Dissertations

Density functional theory (DFT) is a widely used computational method for studying electronic structures of atoms, molecules, and solids. It provides an exact theory for obtaining ground state energy from the ground state density. However, since the exact exchange-correlation functional remains unknown, approximate exchange-correlation functionals called approximate density approximations (DFAs) are used. The foundation of many DFAs is the local spin density approximation (LSDA). It serves as the starting point for constructing various DFAs. However, DFAs are prone to self-interaction errors (SIE) due to the improper cancellation of the approximate exchange energy and the Coulomb energy. This issue impacts the …

Dinitroxides In Rapid Scan Electron Paramagnetic Resonance Imaging, Lukas B. Woodcock

Electronic Theses and Dissertations

Local tissue physiology is an important parameter in understanding disease behavior. Rapid Scan (RS) electron paramagnetic resonance (EPR) offers a unique, non-invasive tool for investigation of these so-called microenvironments through EPR Imaging (EPRI). Research into advancement of EPRI falls into many categories. Not least among those are advances in instrumentation and methodology. Presented here are updates to a benchtop EPRI instrument operating at 1 GHz targeted at pre-clinical EPRI applications. Newly developed methods for reducing RS-EPR background through inversion of the magnetic field are also demonstrated. EPR applications are limited in native biological systems due to the miniscule concentration of …

Electron-Transfer Mediated Photo-Switching In Nanoparticles, Liaoran Cao

All Dissertations

Previous publications from our lab demonstrated viable approaches to design a photo-switching nanoparticle with arguably superior brightness and photostability resulting in an improved resolution in localization-based microscopy, as compared to other photo-switching dyes or particles. As a follow-up, this dissertation is focused on two major tasks: first, developing nanoparticles with better photo-switching properties for super-resolution imaging; second, trying to achieve a better physical picture of the mechanisms involved in photo-switching, including polaron dynamics, charge transfer, and energy transfer. A new class of photo-switchable nanoparticles was developed by blending conjugated polymer semiconductor with fullerene-based electron acceptors, and further blending with polystyrene …

The Influence Of Allostery Governing The Changes In Protein Dynamics Upon Substitution, Joseph Hess

All Dissertations

The focus of this research is to investigate the effects of allostery on the function/activity of an enzyme, human immunodeficiency virus type 1 (HIV-1) protease, using well-defined statistical analyses of the dynamic changes of the protein and variants with unique single point substitutions ¹. The experimental data¹ evaluated here only characterized HIV-1 protease with one of its potential target substrates. Probing the dynamic interactions of the residues of an enzyme and its variants can offer insight of the developmental importance for allosteric signaling and their connection to a protein’s function. The realignment of the secondary structure elements can …

The Investigation Of Singlet Fission From The Perspective Of Hierarchy Of Pure States (Hops), Tao (James) Chen

Chemistry Theses and Dissertations

This thesis provides a preliminary investigation of singlet fission from the perspective of Hierarchy of pure states (HOPS), which provides a numerical exact solution for the investigation of a series of open quantum systems. Since the inception of the concept of singlet fission about half a century ago, this photo-physical process has attracted the attention of a multitude of researchers and has been extensively studied theoretically and experimentally. However, these previous methods for the investigation of singlet fission focus more or less on tackling the underlying mechanisms of singlet fission from the perspective of perturbation. So far, the HOPS method …

The Investigation Of Singlet Fission From The Perspective Of Hierarchy Of Pure States (Hops), Tao (James) Chen

Chemistry Theses and Dissertations

This thesis provides a preliminary investigation of singlet fission from the perspective of Hierarchy of pure states (HOPS), which provides a numerical exact solution for the investigation of a series of open quantum systems. Since the inception of the concept of singlet fission about half a century ago, this photo-physical process has attracted the attention of a multitude of researchers and has been extensively studied theoretically and experimentally. However, these previous methods for the investigation of singlet fission focus more or less on tackling the underlying mechanisms of singlet fission from the perspective of perturbation. So far, the HOPS method …

Band Alignments Of Metal/Oxides-Water Interfaces Using Ab Initio Molecular Dynamics, Yong-Bin Zhuang, Jun Cheng

Journal of Electrochemistry

Band alignments of electrode-water interfaces are of crucial importance for understanding electrochemical interfaces. In the scenario of electrocatalysis, applied potentials are equivalent to the Fermi levels of metals in the electrochemical cells; in the scenario of photo(electro)catalysis, semiconducting oxides under illumination have chemical reactivities toward redox reactions if the redox potentials of the reactions straddle the conduction band minimums (CBMs) or valence band maximums (VBMs) of the oxides. Computational band alignments allow us to obtain the Fermi level of metals, as well as the CBM and VBM of semiconducting oxides with respect to reference electrodes. In this tutorial, we describe …

Ultramicroelectrode Experiments: Principles, Fabrications And Voltmmetric Behaviors, Zhen Ma, Jia-Yang Lin, Wen-Jing Nan, Lian-Huan Han, Dong-Ping Zhan

Journal of Electrochemistry

Due to the small size at least in one dimension (< 25 μm), ultramicroelectrode (UME) has small electric-double-layer capacitance, low IR drop, rapid mass transfer rate, fast response, high signal/noise ratio and high spatiotenporal resolution. UME is qualified not only to study the kinetics of fast electrode processes, but also to act as the probe of scanning electrochemical microscopies to obtain the localized chemical or electrochemical reactivity of the substrates. Thus, UMEs play a significant role in various research domains of electrochemistry, and have become an important electrochemical experimental method. Herein, we will introduce the basic principles, a simple fabrication method and voltammetric experimental protocols of UME, providing a guide to carry out the UME experiments.

Recent Progress Of Bifunctional Electrocatalysts For Oxygen Electrodes In Unitized Regenerative Fuel Cells, Tian-Long Zheng, Ming-Yu Ou, Song Xu, Xin-Biao Mao, Shi-Yi Wang, Qing-Gang He

Journal of Electrochemistry

Unitized regenerative fuel cells (URFCs), which oxidize hydrogen to water to generate electrical power under thefuel cells (FCs) mode and electrolyze water to hydrogen under the water electrolysis (WE) mode for recycling, areknown as clean and sustainable energy conversion devices. In contrast to the hydrogen oxidation reaction (HOR) andhydrogen evolution reaction (HER) on the hydrogen electrode side, the sluggish kinetics of oxygen reduction reaction(ORR) and oxygen evolution reaction (OER) on the oxygen electrode side requires highly efficient bifunctional oxygencatalysts. Conventional precious metal oxygen catalysts combine Pt and IrO₂ with excellent ORR and OER activities toachieve bifunctional electrocatalysis performance, but …

Electrochemical Scanning Tunneling Microscopy: Taking The Initial Stage Of Cu Electrodeposition On Au(111) As An Example, Zhuo Tan, Kai-Xuan Li, Bing-Wei Mao, Jia-Wei Yan

Journal of Electrochemistry

Electrochemical scanning tunneling microscopy (ECSTM) plays an important role in the field of electrochemistry, which can obtain potential-dependent structural information of electrode surface with high spatial resolution and observe some reaction processes in electrolyte solutions, and provide a powerful way to understand the interfacial structure and electrode processes from the perspective of high spatial resolution. In this article, the study of electrodeposition of Cu on Au (111) by ECSTM is taken as an example to introduce the experimental methods required for ECSTM and share our experience with other electrochemical groups. Firstly, the working principle of STM is introduced so that …

High Resolution Intracavity Laser Absorption Spectroscopy Of Transition Metal-Containing Diatomic Molecules, Kristin Bales

Dissertations

Three transition metal-containing diatomic molecules have been studied using intracavity laser spectroscopy. Many of the transitions were recorded using a Fourier-transform spectrometer for detection, allowing collection at Doppler-limited resolution for the gas phase molecules. Several vibrational bands in two electronic transition systems of tantalum fluoride (TaF) have been analyzed, and new molecular constants provided. Transitions involving six electronic states of tungsten sulfide (WS) have been analyzed, with new and updated constants provided, including a deperturbation analysis of three vibrational bands in two of the states. Finally, a fresh perspective on two electronic states of tungsten oxide (WO) included a deperturbation …

Photophysical Properties Of Synthetic Oligomeric Phenylene Ethynylene, Hugh F. Fritz Jr.

Chemistry and Chemical Biology ETDs

Oligomeric Phenylene Ethynylenes (OPEs) are a class of synthetically prepared compounds with the basic structure of phenylene rings connected by triple-bonded carbon atoms, also known as an ethyne link. This structure can be modified by incorporating functional groups onto one or more of the phenylene rings. The addition of functional groups, such as sulfoxide or imidazole, may alter the photophysical properties in detectable ways. The photophysical techniques used in this report include fluorescence, spectroscopy in the ultraviolet and visible light range (UVVIS), and photon-based excitation using a photo chamber.

One attractive function of OPEs is their antimicrobial property. Previously published …

Adsorption Performance Of Mg0.33ni0.33co0.33fe2o4 Nanoparticles Doped With Gadolinium And Lanthanum For Lead (Ii) Removal, Mariam Rabaa, Amani Aridi, Ghassan Younes, Ramadan Awad

BAU Journal - Science and Technology

The issue of water pollution has become a major concern in recent times, and the need for effective strategies for treating contaminated water sources has become more urgent. One promising approach that has been gaining attention in the field of wastewater treatment is the use of nano-ferrites. In this regard, novel Mg_0.33Ni_0.33Co_0.33La_xFe_2-xO₄ and Mg_0.33Ni_0.33Co_0.33Gd_xFe_2-xO₄ nanoparticles (NPs), where x = 0.00, 0.01 and 0.08, were synthesized to test their adsorption performance for the removal of Pb (II). The structural …