Orientador: Vitor Baranauskas / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-11T10:03:42Z (GMT). No. of bitstreams: 1 Roos_Mathias_M.pdf: 4816472 bytes, checksum: 51a357faa29ccbd01723b1d6ca5abf27 (MD5) Previous issue date: 2007 / Resumo: Na primeira parte deste trabalho amostras de diamante poli-cristalino dopado com boro foram crescidas por deposição química a vapor assistida por filamento quente. As características de emissão de campo foram investigadas. A dopagem (NB) em amostras diferentes foi variada pelo controle da concentração B/C no fluxo de gases durante o processo de crescimento. Os campos limiares (Eth) para emissão de campo foram medidos e relacionados com as concentrações B/C usadas. Assim, a influência das bordas entre os grãos, a dopagem e a morfologia da superfície na emissão de campo foram investigadas. A saturação da dopagem foi observada para altas concentrações B/C. O transporte de cargas através das bordas entre os grãos e as propriedades locais de emissão na superfície foram modeladas por dois mecanismos que afetam a emissão de campo. Correntes de emissão de 500 nA·cm-2 foram obtidas para campos elétricos de 8 V·µm-1. Na segunda parte desta tese, a construção de um novo sistema de ultra alto vácuo (UHV) para realizar medições de emissão de campo é descrita. A construção inclui o projeto integral de uma câmara de UHV com sistema de bombas, conjunto de manipuladores, suportes mecânicos e a infraestrutura do laboratório / Abstract: In the first part of this thesis, the study of field emission properties of hot filament chemical vapor deposited boron doped polycrystalline diamond is described. The doping level (NB) of different samples was varied controlling the B/C concentration in the gas feed during the growth processes. The threshold field (Eth) for electron emission in dependence on different B/C concentrations was measured and the influence of grain boundaries, doping level and surface morphology on the field emission properties was investigated. For high B/C ratios doping saturation was observed. Carrier transport through conductive grains and local emission properties of surface sites figured out to be two independent limiting effects on field emission. Emitter currents of 500 nA·cm-2 were obtained using electric fields less than 8 V·µm-1. In the second part the construction of a new UHV system for field emission measurements is described, including the complete project of a UHV chamber with pump system, manipulators and sample transfer system, mechanical supports and the infrastructural requirements of the laboratory / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Nos últimos 30 anos o crescimento paralelo das Ciências de Superfície tradicionais, em ambiente de ultra-alto vácuo (UHV), com a Eletroquímica levou ao nascimento de um novo campo interdisciplinar: Física de Superfície e Eletroquímica. Técnicas de ambas as áreas dão informações complementares e assim, quando realizadas em conjunto podem fornecer muitas respostas em nível atômico, estrutural e eletrônico quando o eletrodo está em contato com a solução eletrolítica. A intenção primordial dessa Dissertação foi o estudo fundamental das fases ricas em oxigênio presentes na superfície de Ru(0001) através de caracterizações eletroquímicas e morfológicas utilizando um sistema que permitiu o acoplamento de uma célula eletroquímica miniatura de fluxo a câmaras de UHV. Inicialmente exibi-se a modificação e a construção de equipamentos necessários para a preparação do sistema binário Au-Pt(111) e do óxido monocristalino Ru2O(110). Imagens de STM em escala morfológica mostraram o crescimento anisotrópico do filme de RuO2(110) sobre um substrato monocristalino de Ru(0001). Resultados obtidos através da técnica de Voltametria Cíclica na eletrooxidação de CO em RuO2(110) corroboraram cálculos teóricos sobre a estrutura da superfície quando esta em ambiente úmido. Superfícies modelos baseadas em ouro, crescido epitaxialmente sobre um substrato de Pt(111), foram preparadas no sistema de UHV. Dados eletroquímicos foram correlacionados às composições superficiais destas, mostrando o efeito do substrato prevalecendo sobre o efeito eletrônico. / In the last 30 years the parallel growth of the traditional Surface Science, under UHV environment, and Electrochemistry gave rise to a new interdisciplinary field: Surface Science and Electrochemistry. Techniques from both sciences give complementary information. Thus, in tandem, they are able to elucidate many atomic, structural and electronic phenomena, of an electrode in contact with a solution. The main goal of this Dissertation was the fundamental study of the Oxygen-rich Ru(0001) surface through electrochemical and morphologic characterizations using a coupled system which allowed the attachment of a miniature flow cell to UVH-chambers. Initially it is shown the construction and modifications of required equipments for the preparation of the binary system Au-Pt(111) and single crystal RuO2(110) oxide. Attainable morphological STM images demonstrated the anisotropic growth of the RuO2(110) over a Ru(0001) substrate. Results of the electrooxidation of CO on RuO2(110), obtained by means of Cyclic Voltammetry, corroborated theoretical calculations concerning the oxide superficial structure in a humid environment. Model surfaces based on Au, epitaxialy grown on a Pt(111) substrate, were prepared under UHV conditions. Electrochemical data and superficial composition were correlated, confirming that the substrate effect overcomes electronic strain effects.

A global shift towards reducing carbon (CO2) emissions in the automotive industry while increasing fuel efficiency and range security has triggered the exploration of new processing routes and material alternatives for automotive components. To achieve such goals, manufacturing processes such as high vacuum high pressure die casting (HV-HPDC) have gained attention in recent years to fabricate cast Al alloys for structural automotive components. HV-HPDC allows for increased and more economical production as compared to other manufacturing methods due to the minimal steps involved in the process. Higher degrees of tolerance and precision can be upheld with HV-HPDC, ceasing the need for secondary operations to form the component into desired complex shapes. In this research, the effect of pre-solidified grains (PSG) and heightened metal residence time on the microstructure and mechanical properties were investigated in a new heat-treatable casting alloy, (Al-1.1wt%Fe-4.7wt%Zn-0.95wt%Mg)-0.07wt%Ti, also known as Nemalloy HE700 alloy, manufactured via HV-HPDC. Developed at McMaster University in conjunction with Nemak USA/CAN and CanmetMATERIALS, Nemalloy HE700 alloy is intended for structural automotive applications with its higher strength and increased light weighting capabilities. Nemalloy HE700 serves as a suitable candidate to replace existing Al-Si alloys such as Aural-5 (Al-8wt%Si-Mg-Mn), currently used in the market today. As-cast test plate castings adhering to two geometries: a 3-step plate geometry (nominal plate thicknesses of 3 mm, 2.5 mm, and 2.3 mm) and a singular plate (2.5 mm) with increasing shot delay intervals of 3 additional seconds to a total of 10 seconds from normal operating conditions (i.e., 1, 4, 7, and 10 seconds) were fabricated with the intention of increasing PSG content within the final cast components to study the underlying effects. Experimental efforts through metallography revealed that, much like traditional high pressure die cast (HPDC) components, PSG gravitated toward the centers of the castings in all operating conditions with heightened agglomerations and potential abnormal grain growth in higher delay samples. Moreover, distributions of PSG became more dispersed through the cross-sections as the delay time was increased. Size distributions of PSG adhered to a standard characteristic grain of 100 µm to sizes of 1000+ µm. Larger sizes of PSG grew substantially in equivalent circular diameter (ECD) and extent in higher delay interval samples. Affected area percentage as a result of an increase in PSG content uncovered higher degrees of porosity presenting themselves as shrinkage and gas porosities in the microstructure. A rise in gas porosity size and quantity was realized with higher delay intervals. Uniaxial mechanical testing of tensile specimens from both geometries indicated a directional relationship of PSG where samples were increasingly more brittle and demonstrated adverse mechanical properties when testing was performed parallel to the metal flow direction as opposed to when performed perpendicularly. Moreover, Nemalloy HE700 alloy exhibited a lower propensity of formation of PSG than Aural-5 in higher levels of shot delay times, primarily due to compositional and differing solidification behaviours of the two alloys. The research presented characterizes the nature of PSG formation in HV-HPDC Al alloys with increased metal residence time and the resultant adverse effects on performance. As efforts shift toward manufacturing structural Al components using HV-HPDC, a greater understanding of such effects will aid in alloy development, die mould design, and disseminate information on HV-HPDC to produce components of heightened quality. Additionally, the resultant findings aim to address gaps in current literature as automotive manufacturers transition from non-structural HPDC components to structural HV-HPDC products for commercial use. / Thesis / Master of Applied Science (MASc)

No description available.

The growth of Co (0001) films and Cr2O3 (0001)/Co (0001) has been investigated using surface analysis methods. Such films are of potential importance for a variety of spintronics applications. Co films were directly deposited on commercial Al2O3 (0001) substrates by magnetron sputter deposition or by molecular beam epitaxy (MBE), with thicknesses of ~1000Å or 30Å, respectively. Low Energy Electron Diffraction (LEED) shows hexagonal (1x1) pattern for expected epitaxial films grown at 800 K to ensure the hexagonally close-packed structure. X-ray photoemission spectroscopy (XPS) indicates the metallic cobalt binding energy for Co (2p3/2) peak, which is at 778.1eV. Atomic force microscopy (AFM) indicates the root mean square (rms) roughness of Co films has been dramatically reduced from 10 nm to 0.6 nm by optimization of experiment parameters, especially Ar pressure during plasma deposition. Ultrathin Cr2O3 films (10 to 25 Å) have been successfully fabricated on 1000Å Co (0001) films by MBE. LEED data indicate Cr2O3 has C6v symmetry and bifurcated spots from Co to Cr2O3 with Cr2O3 thickness less than 6 Å. XPS indicates the binding energy of Cr 2p(3/2) is at 576.6eV which is metallic oxide peak. XPS also shows the growth of Cr2O3 on Co (0001) form a thin Cobalt oxide interface, which is stable after exposure to ambient and 1000K UHV anneal.

Diborane (B2H6) is a hydride gas often employed in high-purity industrial surface processes such as chemical vapor deposition or epitaxial layer growth. The use of diborane at industrial scales is complicated by the formation of higher-order borane contaminants in pure diborane gas via a complex series of gas-phase reactions. An advanced, rationally designed sorbent could stabilize diborane through interfacial interactions, dramatically reducing the decomposition rate without permanently trapping the molecule. However, the design of such a sorbent would require a nuanced understanding of diborane's fundamental surface chemistry, about which little is known. In the work presented in this thesis, a novel ultra-high vacuum (UHV) system was designed and employed to characterize the fundamental interactions of diborane with a variety of surfaces. In situ Fourier-transform infrared (FTIR) spectroscopy and temperature-programmed desorption (TPD) experiments were used in conjunction with density-functional theory (DFT) calculations to elucidate binding geometries and interaction mechanisms. On non-functionalized model surfaces such as CaF2 or amorphous carbon, diborane adsorbed only at cryogenic temperatures. Hydroxylated surfaces such as amorphous silica (SiO2) adsorbed significantly more diborane, which remained at slightly higher temperatures. FTIR spectra indicated the presence of hydrogen bonding between diborane and surface hydroxyl groups. DFT calculations revealed that the interaction takes the form of a novel bifurcated dihydrogen bond. In contrast with previous reports, diborane exhibited only weak interactions with the surface hydroxyl groups of silica. DFT calculations further elucidated that the irreversible reaction of diborane with surface hydroxyls is only possible in the presence of a second nucleophile (such as adventitious water). On the metal-organic framework (MOF) UiO-66 NH2, unique chemistry was observed in which diborane reacted with the –NH2 groups of the MOF linkers, yielding stable surface-bound products. DFT calculations determined the reaction mechanism to be dissociative adsorption of diborane, resulting in two amine-bound –BH3 moieties. Importantly, it was found that these fragments persisted at room temperature and could only leave the surface via the reverse reaction. The discovery that diborane can be stored as separate fragments that re-combine to yield the parent molecule has important implications for the development of new diborane sorbents. We hypothesize that surfaces designed with fixed, precisely spaced nucleophiles could enable the reversible storage of diborane. / Doctor of Philosophy / Diborane (B2H6) is a useful but hazardous gas employed in both academia and industry, often in processes that require ultra-high-purity source gases. However, diborane reacts with itself at room temperature, making the contamination of pure diborane very difficult to avoid. This problem could potentially be solved with a specially designed solid material that would sequester diborane without destroying it, but the design of such a material would require a much better understanding of diborane's chemistry with surfaces than currently exists. In this work, we employed ultra-high vacuum (UHV) methods to study the interactions between diborane and a variety of surfaces, with the ultimate goal of determining guiding principles for the design of diborane-stabilizing sorbents. Among the materials we studied were inorganic carbon, silica (SiO2), and a class of advanced microporous materials known as metal-organic frameworks (MOFs). Inorganic materials were found not to interact meaningfully with diborane. A novel hydrogen bond was discovered between diborane and the surface of silica, but the interaction was found to be too weak to provide significant stabilization. Most MOFs behaved similarly to silica. The MOF UiO-66-NH2, however, was found to react with diborane. Through a combination of computer simulations and UHV experiments, the precise nature of the reaction was determined. On the surface of UiO 66 NH2, diborane splits into two surface-bound BH3 molecules, where it is trapped until the reaction reverses. Importantly, it was found that BH3 can only leave the surface by recombining into diborane—effectively storing diborane on the surface to be released later. We hypothesize that this useful chemistry is due to the fixed distance between chemical groups on the MOF surface. This discovery suggests a promising strategy for the design of advanced diborane sorbents.

Detailed understanding of the kinetics and mechanisms of heterogeneous reactions between gas-phase nitrate radicals, a key nighttime atmospheric oxidant, and organic particles will enable scientists to predict the fate and lifetime of the particles in the atmosphere. In an effort to acquire knowledge of interfacial reactions of nitrate radical with organics, model surfaces are created by the spontaneous adsorption of methyl-/vinyl-/hydroxyl-terminated alkanethiols on to a polycrystalline gold substrate. The self-assembled monolayers provide a well-defined surface with the desired functional group (-CH3, H2C=CH-, or HO-) positioned precisely at the gas-surface interface. The experimental approach employs in situ reflection-absorption infrared spectroscopy (RAIRS) to monitor bond rupture and formation while a well-characterized flux of NO3 impinges on the organic surface. Overall, the reaction kinetics and mechanisms were found to depend on the terminal functional group of the SAM and incident energy of the nitrate radical (NO3). For reactions of the H2C=CH-SAM with NO3, the surface reaction kinetics obtained from RAIRS reveals that the consumption rate of the terminal vinyl groups is nearly identical to the formation rate of a surface-bound nitrate species and implies that the mechanism is one of direct addition to the vinyl group rather than hydrogen abstraction. Upon nitrate radical collisions with the surface, the initial reaction probability for consumption of carbon-carbon double bonds was determined to be (2.3 ± 0.5) -- 10-3. Studies of reactions of HO-SAM with the effusive source of NO3 suggest that the reaction between NO3 and the HO-SAM is initiated by hydrogen abstraction at the terminal - 'CH2OH groups with the initial reaction probability of (6 ± 1)-- 10-3. An Arrhenius plot was obtained to measure the activation energy of the H abstraction from the HO-SAM. Further, for reactions of the HO-SAM with the high incident energy of NO3 molecules created by molecular beam, the reaction probability for H abstraction at the hydroxyl terminus was determined to be ~0.4. The significant increase in the reaction probability was attributed to the promotion in the ability of NO3 abstracting hydrogen atom at the methylene groups along hydrocarbon chains. The reaction rates of NO3 with the model organic surfaces that have been investigated are orders of magnitude greater than the rate of ozone reactions on the same surfaces which suggests that oxidation of surface-bound organics by nighttime nitrate radicals may play an important role in atmospheric chemistry despite their relative low concentration. X-ray photoelectron spectroscopy (XPS) data suggests that oxidation of the model organic surfaces by NO3 leads to the production of organic nitrates, which are stable for a period time. In addition, the effect of background gases on reactions of NO3 with model organic surfaces needs further investigations at atmospheric pressures. The results presented in this thesis should help researchers to predict the fate and environmental impacts of organic particulates with which nitrate radicals interact. / Ph. D.

Metal oxide and metal oxide-supported metal nanoparticles can adsorb and decompose chemical warfare agents (CWAs) and their simulants. Nanoparticle activity depends on several factors including chemical composition, particle size, and support, resulting in a vast number of materials with potential applications in CWA decontamination. Current instrumentation in our laboratory used to investigate fundamental gas-surface interactions require extensive time and effort to achieve operating conditions. This thesis describes the design and construction of a high-throughput, high vacuum surface analysis instrument capable of studying interactions between CWA simulants and nanoparticulate surfaces. The new instrument is small, relatively inexpensive, and easy to use, allowing for expeditious investigations of fundamental interactions between gasses and nanoparticulate samples. The instrument maintains the sample under high vacuum (10?⁷-10?⁹ torr) and can reach operating pressures in less than one hour. Thermal control of the sample from 150-800 K enables sample cleaning and thermal desorption experiments. Infrared spectroscopic and mass spectrometric methods are used concurrently to study gas-surface interactions. Temperature programmed desorption is used to estimate binding strength of adsorbed species. Initial studies were conducted to assess the performance of the instrument and to investigate interactions between the CWA simulant dimethyl methylphosphonate (DMMP) and nanoparticulate silicon dioxide. / Master of Science

Understanding interfacial interactions at the molecular level is important for interpreting and predicting the dynamics and mechanisms of all chemistry processes. A thorough understanding of the interaction dynamics and energy transfer between gas molecules and surfaces is essential for the study of various chemical reactions. The collisions of diatomic molecules on organic surfaces are crucial to the study of atmospheric chemistry. Molecular beam scattering experiments performed in ultra-high vacuum chambers provide insight into the dynamics of gas-surface interactions. Many questions remain to be answered in the study of gas-surface interfacial chemistry. For example, what affects the energy transfer between gas molecules and surfaces? How do intermolecular forces affect the interfacial interaction dynamics? We have approached these questions by scattering diatomic gas molecules from functionalized self-assembled monolayers (SAMs). Our results indicate that the intermolecular forces between gas molecules and surfaces play an important role in the energy transfer processes. Moreover, the stronger the intermolecular forces, the more often the incident molecules come into thermal equilibrium with the surface. Furthermore, most of the previous approaches toward understanding gas-surface interaction dynamics considered the interactions as independent incidents. By scattering O2, N2, CO and NO on both CH3- and OH- terminated SAM, we found a correlation between the gas-surface interactions and a bulk property, solubility. Both being strongly affected by intermolecular forces, the gas-surface energy transfer and solubility of gases in surface-similar solvents (water for OH-SAM, n-hexane for CH3-SAM) have a positive correlation. This correlation facilitates the understanding of interfacial dynamics at the molecular level, and helps predict the outcome of the similar-size gas collisions on surfaces. / Master of Science

A molecular-level understanding of gas-surface energy exchange and reaction mechanisms will aid in the prediction of the environmental fate of pollutants and enable advances toward catalysts for the decomposition of toxic compounds. To this end, molecular beam scattering experiments performed in an ultra-high vacuum environment have provided key insights into the initial collision and outcome of critical interfacial processes on model systems. Results from these surface science experiments show that, upon gas-surface collisions, energy transfer depends, in subtle ways, on both the properties of the gas molecules and surfaces. Specifically, model organic surfaces, comprised of long-chain methyl- and hydroxyl-terminated self-assembled monolayers (SAMs) have been employed to test how an interfacial hydrogen bonding network may affect the ability of a gas-phase compound to thermally accommodate (typically, the first step in a reaction) with the surfaces. Results indeed show that small organic compounds transfer less energy to the interconnected hydroxyl-terminated SAM (OH-SAM) than to the organic surface with methyl groups at the interface. However, the dynamics also appear to depend on the polarizability of the impinging gas-phase molecule. The π electrons in the double bond of ethene (C2H4) and the triple bond in ethyne (C2H2) appear to act as hydrogen bond acceptors when the molecules collide with the OH-SAM. The molecular beam scattering studies have demonstrated that these weak attractive forces facilitate energy transfer. A positive correlation between energy transfer and solubilities for analogous solute-solvent combinations was observed for the CH3-SAM (TD fractions: C2H6 > C2H4 > C2H2), but not for the OH-SAM (TD fractions: C2H6 > C2H2 > C2H4). The extent of energy transfer between ethane, ethene, and ethyne and the CH3-SAM appears to be determined by the degrees of freedom or rigidity of the impinging compound, while gas-surface attractive forces play a more decisive role in controlling the scattering dynamics at the OH-SAM. Beyond fundamental studies of energy transfer, this thesis provides detailed surface-science-based studies of the mechanisms involved in the uptake and decomposition of chemical warfare agent (CWA) simulants on or within metal-organic frameworks (MOFs). The work presented here represents the first such study reported in with traditional surface-science based methods have been applied to the study of MOF chemistry. The mechanism and kinetics of interactions between dimethyl methylphosphonate (DMMP) or dimethyl chlorophosphate (DMCP), key CWA simulants, and Zr6-based metal-organic frameworks (MOFs) have been investigated with in situ infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD), and DFT calculations. DMMP and DMCP were found to adsorb molecularly (physisorption) to the MOFs through the formation of hydrogen bonds between the phosphoryl oxygen and the free hydroxyl groups associated with Zr6 nodes or dangling -COH groups on the surface of crystallites. Unlike UiO-66, the infrared spectra for UiO-67 and MOF-808, recorded during DMMP exposure, suggest that uptake occurs through both physisorption and chemisorption. The XPS spectra of MOF-808 zirconium 3d electrons reveal a charge redistribution following exposure to DMMP. Besides, the analysis of the phosphorus 2p electrons following exposure and thermal annealing to 600 K indicates that two types of stable phosphorus-containing species exist within the MOF. DFT calculations (performed by Professor Troya at Virginia Tech), were used to guide the IR band assignments and to help interpret the XPS features, suggest that uptake is driven by nucleophilic addition of a surface OH group to DMMP with subsequent elimination of a methoxy substituent to form strongly bound methyl methylphosphonic acid (MMPA). With similar IR features of MOF-808 upon DMCP exposure, the reaction pathway of DMCP in Zr6-MOFs may be similar to that for DMMP, but with the final product being methyl chlorophosphonic acid (elimination of the chlorine) or MMPA (elimination of a methoxy group). The rates of product formation upon DMMP exposure of the MOFs suggest that there are two distinct uptake processes. The rate constants for these processes were found to differ by approximately an order of magnitude. However, the rates of molecular uptake were found to be nearly identical to the rates of reaction, which strongly suggests that the reaction rates are diffusion limited. Overall, and perhaps most importantly, this research has demonstrated that the final products inhibit further reactions within the MOFs. The strongly bound products could not be thermally driven from the MOFs prior to the decomposition of the MOFs themselves. Therefore, new materials are needed before the ultimate goal of creating a catalyst for the air-based destruction of traditional chemical nerve agents is realized. / Doctor of Philosophy / A molecular-level understanding of gas-surface energy exchange and reaction mechanisms will aid in the prediction of the environmental fate of pollutants and enable advances toward catalysts for the decomposition of toxic compounds. Our gas-surface scattering experiments performed in an ultra-high vacuum environment have provided key insights into the outcome of critical interfacial processes on model systems. Results show that energy transfer upon gas-surface collisions depends on both the properties of the gas molecules and surfaces. Due to the formation of interfacial hydrogen bonding network in hydroxyl-terminated surface, the small organic compounds transfer less energy to it than to the organic surface with methyl groups at the interface. The dynamics also appear to depend on the properties of the impinging gas-phase molecule. The π electrons in the double bond of ethene and the triple bond in ethyne act as hydrogen bond acceptors when the molecules collide with the hydroxyl-terminated surface. The attractive forces facilitate energy transfer. A positive correlation between energy transfer and solubilities for analogous solute-solvent combinations was observed for the methyl-terminated surface, but not for the hydroxyl-terminated surface. The extent of energy transfer between ethane, ethene, and ethyne and the methyl-terminated surface appears to be determined by the degrees of freedom or rigidity of the gas, while gas-surface attractive forces play a more decisive role in controlling the scattering dynamics at the hydroxyl-terminated surface. Furthermore, this thesis provides detailed surface-science-based studies of the mechanisms involved in the uptake and decomposition of chemical warfare agent (CWA) simulants on or within metal-organic frameworks (MOFs). Dimethyl methylphosphonate (DMMP) and dimethyl chlorophosphate (DMCP), key CWA simulants, physisorbed to the MOFs through the formation of hydrogen bonds between the phosphoryl oxygen and the free hydroxyl groups associated with inorganic nodes or dangling -COH groups on the surface of crystallites. The infrared spectra for UiO-67 and MOF-808 suggest that uptake occurs through both physisorption and chemisorption. The XPS spectra of MOF-808 zirconium 3d electrons reveal a charge redistribution following exposure to DMMP. Besides, the analysis of the phosphorus 2p electrons following exposure and thermal annealing to 600 K indicates that two types of stable phosphorus-containing species exist within the MOF. DFT calculations suggest that uptake is driven by nucleophilic addition of a surface OH group to DMMP with subsequent elimination of a methoxy substituent to form strongly bound methyl methylphosphonic acid (MMPA). With similar IR features of MOF-808 upon DMCP exposure, the reaction pathway of DMCP in MOFs may be similar to that for DMMP, but with the final product being methyl chlorophosphonic acid (elimination of the chlorine) or MMPA (elimination of a methoxy group). The rates of product formation suggest that there are two distinct uptake processes. The rate constants for these processes were found to be nearly identical to the rates of physisorption, which suggests that the reaction rates are diffusion limited. Overall, this research has demonstrated that the final products inhibit further reactions within the MOFs. The strongly bound products could not be thermally driven from the MOFs prior to the decomposition of the MOFs themselves. Therefore, new materials are needed before the ultimate goal of creating a catalyst for the air-based destruction of traditional chemical nerve agents is realized.