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Full-Text Articles in Chemistry

Understanding The Role Of Atom Trapping In The Evolution Of Hydrocarbon Transformation Catalyst Morphology, Griffin Canning Dec 2020

Understanding The Role Of Atom Trapping In The Evolution Of Hydrocarbon Transformation Catalyst Morphology, Griffin Canning

Chemistry and Chemical Biology ETDs

Converting alkanes to other, more chemically and economically valuable molecules requires catalysts that can survive elevated temperatures and highly reducing environments. These environments can cause many metal-nanoparticle based catalysts to sinter rapidly, causing a loss of activity. They must also tolerate the coke formation, as well, since coke can restrict access to active sites by gas phase molecules, thus lowering catalytic activity. While there are routes to improve both the sinter and coke resistance of catalysts, an alternative strategy is to develop a protocol for regenerating the activity of the catalyst in question when coke formation or sintering becomes problematic. …


Atom Trapping And Its Role On The Nucleation & Growth Of Platinum Nanoparticles, Deepak Kunwar Nov 2020

Atom Trapping And Its Role On The Nucleation & Growth Of Platinum Nanoparticles, Deepak Kunwar

Chemistry and Chemical Biology ETDs

Diesel oxidation catalysts deactivate due to Pt sintering, a major problem in automotive industries. To make sure they operate effectively throughout the lifetime of the vehicle, automotive industries are putting an excessive amount of Pt. There is a need to develop a catalyst that serves long term performance with minimal use of Pt. Jones et al.1 demonstrated that ceria traps Pt atoms. His work generated some logical and valid questions such as what is the mechanism for the formation of anomalously large Pt particles? What is the upper limit of Pt metal loading in the form of single atoms …


Small Molecule Analog Studies Of Paramagnetic Dmso Reductase Enzyme Family Intermediates, Khadanand Kc Jul 2020

Small Molecule Analog Studies Of Paramagnetic Dmso Reductase Enzyme Family Intermediates, Khadanand Kc

Chemistry and Chemical Biology ETDs

Pyranopterin molybdenum and tungsten enzymes are expressed in numerous organisms from all domains of life. These enzymes catalyze a variety of atom, hydride, and electron transfer reactions. The enzymes are of great importance in the biogeochemical cycles of nitrogen, carbon, and sulfur. In recent years, chemists have investigated applications for some of these enzymes as industrial biocatalysts. The dimethylsulfoxide reductase (DMSOr) enzyme family is the broadest family of pyranopterin Mo enzymes. The first coordination sphere of the Mo or W-containing active site for each member of this family is made up of 4 sulfur donors from the two pyranopterin dithiolenes …


Charge Transfer And Plasmon-Pumped Molecular Excitation Mechanisms In Surface Enhanced Photochemistry, Tefera Entele Tesema May 2020

Charge Transfer And Plasmon-Pumped Molecular Excitation Mechanisms In Surface Enhanced Photochemistry, Tefera Entele Tesema

Chemistry and Chemical Biology ETDs

Photochemistry that can be driven at low incident photon flux on optically excited plasmonic nanoparticles is attracting increasing research interest because plasmon-driven reactions offer new pathways for efficient conversion of the abundant solar energy into fuel. The confinement of the electromagnetic field by plasmonic metal nanoparticle and consequent field enhancement gives a dual advantage of ultrasensitive in situ and operando spectroscopic methods to monitor enhanced field-driven photochemical transformation. Charge carrier driven either via direct or indirect excitation mechanism are well-established pathways in plasmon-driven reactions to date. However, the excitation mechanism via plasmon-pumped electron transition from an occupied molecular orbital (HOMO) …