Physical Chemistry Commons^™

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 …

Surface Enhanced Raman Spectroscopy (Sers) As A Nanoscale Adsorption Phenomenon: Development Of Tailored Nanomaterials For Applications In Drug Detection, Chiara Deriu

FIU Electronic Theses and Dissertations

Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique in which nanostructured substrates amplify the inherently weak Raman signal of an adsorbed species by several orders of magnitude, enabling the detection of trace compounds, up to the single molecule level. While this may be an exceptional tool for any analytical scientist, SERS is at present relegated to the role of academic sensation, and is underutilized in everyday analytical practice. The SERS community is increasingly attributing this setback to a poor understanding of nanoscale surfaces and their chemical environment; since molecular adsorption at the nanostructured surface enables SERS detection, uncertainty about …

An Atomistic Study Of The Effects On Mechanical Properties And Bonding Interactions Of Carbon Nanofillers In Nylon 6 Nanocomposites, Michael Roth

Dissertations

Polymers have potential for a wide range of applications. The effectiveness of polymers can be further enhanced through the addition of nanofillers that improve thermal, mechanical, and electrical properties of the polymer. Carbon based nanofillers such as carbon nanotube (CNT), graphene, and carbon nanofibre (CNF) are of particular interest due to their high properties and high aspect ratios. However, limited understanding of the governing interactions of these nanofillers with polymers limits the effectiveness of the final nanocomposite.

The first facet of this dissertation focuses on determining the dominating interactions between pristine CNT and graphene with nylon 6 monomer and the …

Physicochemical, Spectroscopic Properties, And Diffusion Mechanisms Of Small Hydrocarbon Molecules In Mof-74-Mg/Zn: A Quantum Chemical Investigation, Gemechis Degaga

Dissertations, Master's Theses and Master's Reports

In petroleum refining industries, the fracturing process allows for the cracking of long-chain hydrocarbons into a mixture of small olefin and paraffin molecules that are then separated via the energetically and monetarily demanding cryogenic distillation process. In an attempt to mitigate both energetic and capital consumptions, selective sorption of light hydrocarbons by tunable sorbents, such as metal-organic frameworks (MOFs), appears to be the most promising alternative for a more efficient gas separation process. MOFs are novel porous materials assembled from inorganic bricks connected by organic linkers. From a crystal engineering stand point, MOFs are advantageous in creating a range …

From Dye Sensitized Solar Cells To Organic Field Effect Transistors: A Computational Investigation Into The Structural And Electronic Properties Of Novel Phthalocyanines, Patrick J. Dwyer

Seton Hall University Dissertations and Theses (ETDs)

Phthalocyanines (Pc) have gained intense research attention in many diverse application areas due to their highly tunable electronic and structural properties through modification of the molecular periphery and metal center. Throughout this work a series of novel perfluoro-isopropyl substituted MPc have been investigated through theoretical methods. First, the synthetic mechanisms of these Pcs will be explored to gain insight into the experimentally observed Pc product distribution. By examining the electronic structure and formation energies of the various Pc precursors, we explain the product distribution as well as propose the formation of additional Pcs, which were not currently believed to form. …

Density Functional Theory Studies Of Surface-Enhanced Raman Spectroscopy In Electrochemical Interfaces, Liu-Bin Zhao, De-Yin Wu, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Quantum chemical density functional theory and Raman scattering theory were used to study the bonding mechanism and surface-enhanced Raman spectroscopy of pyridine adsorbed on transition metals (Ⅷ group) and coinage metals (IB group) . SERS studies of pyridine-metal systems have been reviewed. Chemical bonding mechanism as well as photo-driven charge transfer mechanism was considered to investigate the vibrational frequency shift and the enhancement of SERS intensity in electrochemical interfaces. Our theoretical results can be used to interpret the SERS phenomena dependent on metals,excitation wavelengths,and applied potentials.

Electrocatalysis In Polymer Electrolyte Membrane Fuel Cells, Li Li, Si-Guo Chen, Xue-Qiang Qi, Yao-Qiong Wang, Meng-Bo Ji, Lan-Lan Li, Zi-Dong Wei

Journal of Electrochemistry

This review presents the study of Chongqing University in electrocatalysis for polymer electrolyte membrane fuel cells(PEMFCs).Based on the understanding to the performance degradation of PEMFCs' catalysts,the university has being concentrated on how to increase the activity,stability and utility of noble metal catalysts.It covers the molecular design of near-surface alloy catalysts for improvement of activity to oxygen reduction reaction(ORR) and resistance to foreign poison species,selective deposition of Pt on the so-called "three-phase interface" for a high Pt utility,and invention of anti-flooding electrode against water flooding in the catalyst layer of the membrane assemble electrode(MEA),and so on.The catalytic mechanism of electrode reactions …