Percent within limits (PWL) is a commonly used quality control/quality assurance measure of highway pavement materials and construction, and it is a popular index for adjusting pay factors. However, PWL is based on the assumption of normal distribution of quality characteristics (e.g., concrete compressive strength and asphalt air voids). Skewness and kurtosis, which are common forms of statistical nonnormal distributions, can potentially bias the acceptance pay factor calculations. To examine this potential pay bias, simulations were performed to investigate the magnitude and the direction (overestimation or underestimation) of pay factor calculations. The study revealed that for both one-sided and two-sided specification limits, bias in pay factors not only did vary in magnitude but also reversed in direction over various ranges of PWL. These analyses showed that for a one-sided upper specification limit, on average, a positive skewness and kurtosis can underestimate the pay factor of an acceptable quality level population by 0.90%, and overestimates a rejectable quality level population by 3.8%. This leads to falsely penalizing acceptable products and rewarding bad products. The same was true for two-sided limits, which again varied based upon the percent of defective materials at the tails of the distribution. This is a very important issue because these biases in pay factors can easily upset the relative profit margins of the contractor. Furthermore, this may not be easily detectable without a detailed and sophisticated analysis as outlined in this paper. For multiple quality characteristics based pay factors, analyses showed that the combined magnitude of these biases was not linearly cumulative. Findings of the study indicate that bias in pay was higher for lots with fewer sublots and higher skewness and kurtosis.

Characterization of small precipitates is important for development of new alloys. One inherent  difficulty  in  characterisation  of  small  precipitates  with  electron microscopy techniques  while  the  particles  are  embedded  in  the  matrix,  is  that the surrounding bulk material will contribute to the analysed signal- limiting, for example, the quantification of the composition of particles.  In order to avoid the matrix contribution, the extraction replica technique was developed in the 1950's. Extraction replicas are made by extracting only the particles from a material onto a thin film for further analysis by scanning or transmission electron microscopy. Different types of particles can be examined by this technique, including various carbides, nitrides, oxides and borides, as well as many intermetallic phases.  In this work, direct replication techniques were compared to two-stage replication for low-alloyed steel, concluding that both are suitable for qualitative analysis, but direct replication is preferred for quantitative analysis.  Successful replication of the zirconium-based Zirlo and the stainless steel 254 SMO was performed, where the precipitated phases were isolated and the composition quantified.   Particle extraction was successful also for the zirconium-based Zircaloy-2 and two types of  aluminium  alloys,  but  no  quantification of  composition  could  be  made  due to different problems associated with etching of each alloy, showing that properchoice of etchant is crucial for the quality of the replicas. / Karaktärisering av små utskiljningar är viktigt för utveckling av nya legeringar. En svårighet  vid  karaktärisering  av  små  utskiljningar  med elektronmikroskopi när partiklarna  sitter  kvar  i  matrisen  är  att  matrisen kommer  ge  ett  bidrag till den analyserade signalen,  därför är t.ex.   möjligheterna för kvantifiering av sammansättning begränsade. För att undvika bidraget från matrisen utvecklades extraktionsrepliker  på  1950-talet.  Extraktionsrepliker  tillverkas  genom  att extrahera partiklar från ett material till en tunn film som sedan kan analyseras med hjälp av svep- eller transmissionselektronmikroskopi. Olika sorters partiklar kan  undersökas  med hjälp  av  denna  metod.     Dessa  inkluderar  olika  typer av  karbider, nitrider, borider, oxider  och  många  olika  sorters  intermetalliska partiklar. I  detta arbete  jämfördes direkta  metoder  med  tvåstegsrepliker  på låglegerat  stål. Slutsatsen  blev  att  båda metoderna  lämpar  sig  för  kvalitativ analys av små partiklar, men direkta metoder är att föredra för kvantitativ analys. Lyckade repliker tillverkades även av zirkoniumlegeringen Zirlo och det rostfria stålet  254  SMO,  där  utskiljningarna  kunde isoleras  och sammansättningen kvantifieras.   Extraktion  av  partiklar  var  lyckad  även  för zirkoniumlegeringen Zircaloy-2  samt  två  typer  av  aluminiumlegeringar, men ingen  kvantifiering  av sammansättningen  kunde  göras  på  grund  av  olika problem  relaterade  till  den valda etsmetoden för varje legering, vilket visar att valet av etsmedel ar avgörande för kvaliteten av replikerna.

<p dir="ltr">The technological drive of humanity to explore the cosmos, travel at hypersonic speeds, and pursue clean energy solutions requires ceramic scientists and engineers to constantly push materials to their functional, behavioral, and chemical extremes. Ultra-high temperature ceramics, and particularly transition metal carbides, are promising materials to meet the demands of extreme environment materials with their >4000 °C melting temperature and impressive thermomechanical behaviors in extreme conditions. The advent of the 2D version of these transition metal carbides, known as MXenes, added a new direction to design transition metal carbides for energy, catalysis, flexible electronics, and other applications. Toward extreme conditions, although MXenes remain yet unexplored, we believe that the ~1 nm flakes of MXenes gives ceramics scientists and engineers the ability to truly engineer transition metal carbides layer-by-layer at the nanoscale to endure the extreme conditions required by future harsh environment technology. Although MXenes have this inherent promise, fundamental study of their behavior in high-temperature environments is necessary to understand how their chemistry and 2D nature affects the high-temperature stability and phase behavior of MXenes toward application in extreme environments.</p><p dir="ltr">In this dissertation, we investigate the high-temperature phase behavior of 2D MXenes in high temperature inert environments to understand the stability and phase transition behavior of MXenes. In this work, we demonstrate that 1) MXenes’ transition at high-temperatures is to highly textured transition metal carbides is due to the homoepitaxial growth of these phases onto ~1-nm-thick MXenes’ highly exposed basal plane, 2) the MXene to MXene interface plays a major role in the phase behavior of MXenes, particularly toward building layered transition metal carbides using MXenes as ~1-nm-thick building blocks, and 3) Defects are the primary site at which atomic migration begins during phase transition of MXenes into these highly textured transition metal carbides, and these defects can be engineered for different phase stability of MXenes. To do so, we investigate the phase behavior of Ti₃C₂T_<em>x</em>, Ta₄C₃T_<em>x</em>, Mo₂TiC₂T_<em>x</em>, and other MXenes using a combination of <i>in situ</i> x-ray diffraction and scanning transmission electron microscopy and other <i>ex situ</i> methods, such as secondary ion mass spectrometry and x-ray photoelectron spectroscopy, with other methods. By investigating the fundamentals of the high-temperature phase behavior of MXenes, we hope to establish the basic principles behind use of MXenes as the ideal material for application in future extreme environments.</p>

Um filme polimérico utilizado na fabricação de curativos adesivos não perfurados deve ter baixo módulo de elasticidade e boa permeabilidade ao vapor d\' água. O baixo módulo de elasticidade garante sensação de maior conforto do produto em contato com a pele quando a pessoa que o está utilizando movimenta a parte do corpo sobre a qual está aplicado o curativo, principalmente a região das articulações, como joelhos e cotovelos. A importância de uma boa permeabilidade ao vapor d\' água está relacionada, principalmente em curativos não perfurados, ao fato de que a pele perde água constantemente e, se o filme polimérico não permitir a saída dessa água ao meio ambiente, ocorrerá um fenômeno denominado maceração, que é a sensibilização excessiva da pele, causada pela hiper hidratação da mesma. O presente trabalho apresenta um estudo da permeabilidade ao vapor d\' água, bem como a caracterização vibracional e térmica de um filme polimérico constituído por três polímeros diferentes, desenvolvido para substituir a poliuretana utilizada atualmente na produção de curativos adesivos não perfurados, com custo inferior. Os polímeros que constituem o filme foram caracterizados separadamente e alguns resultados obtidos, como Tm e a estrutura química dos polímeros Lotader® e Lotryl® foram comparados aos dados fornecidos pelo fabricante. Verificou-se que as propriedades de módulo de elasticidade e permeabilidade ao vapor d\' água do filme desenvolvido são inferiores às da poliuretana inviabilizando a substituição. Entretanto, o trabalho proporcionou um melhor entendimento dos fatores que influenciam o módulo de elasticidade e a permeabilidade do novo material ao vapor d\' água. / A polymeric film must have low elasticity modulus and good water vapor permeation to be used in the production of non perforated adhesive tapes. Low modulus is desirable to provide comfort sensation as the consumer moves the part of his or her body in which the tape is applied on, mainly in the articulations regions, as elbows and knees. The importance of good water vapor permeation is related, mainly in the case of non perforated adhesive tapes with the continuous loss of water by the skin. If the film does not allow the release of the water continuously lost by the skin to the environment, the skin will become very sensitiveness as a result of over hydration. This work presents a study of water permeability and a thermal and vibrational characterization of a polymeric film composed of three different polymers developed to replace the adhesive not perforated polyurethane tape providing lower cost. Besides characterization a test of Water Vapor Transmission Rate (WVTR) was performed. Each polymer present in the film composition was analyzed and the results as Tm and chemical structure of Lotader® e Lotryl® were compared with the producer data. It was verified that the properties of elasticity modulus and water vapor permeability of the new material developed are worse than polyurethane so the substitution can not be performed. However, the work provided a better understanding of the factors that influences the elasticity modulus and water vapor permeability of the new material.

Accurate statistical characterization of nanomaterials is crucial for their use in emerging technologies. This work investigates how different structural characteristics of metal nanoparticles influence the line profiles of the corresponding powder diffraction pattern. The effects of crystallite size, shape, lattice dynamics, and surface strain are all systematically studied in terms of their impact on the line profiles. The studied patterns are simulated from atomistic models of nanoparticles via the Debye function. This approach allows for the existing theories of diffraction to be tested, and extended, in an effort to improve the characterization of small crystallites. It also begins to allow for the incorporation of atomistic simulations into the field of diffraction. Molecular dynamics simulations are shown to be effective in generating realistic structural models and dynamics of an atomic system, and are then used to study the observed features in the powder diffraction pattern. Furthermore, the characterization of a sample of shape controlled Pt nanoparticles is carried out through the use of a developed Debye function analysis routine in an effort to determine the predominant particle shape. The results of this modeling are shown to be in good agreement with complementary characterization methods, like transmission electron microscopy and cyclic voltammetry.

[pt] Nos últimos anos muitos esforços foram realizados para obtenção de materiais capazes de explorar eficientemente a conversão de energia solar. Em particular, a geração de combustíveis por fotocatálise retém grande interesse devido às suas propriedades intrínsecas de promover reações com variação de energia positiva, possibilitando seu armazenamento em compostos químicos. A eficiência desses processos, entretanto, é limitada pela fotoativação dos principais fotocatalisadores no espectro UV, desperdiçando grande parte da energia solar presente no Visível. Neste trabalho foi investigada a influência no desempenho de fotoativação de heteroestruturas de titanatos de Fe e Cu crescidos sobre TiO2 para produção de gás H2 por fotólise da água utilizando luz Visível. As amostras foram preparadas segundo rota por impregnação via úmida e pós-tratamento térmico, em que óxidos metálicos foram formados na superfície de partículas de TiO2 com posterior interdifusão e formação de fases ternárias de Fe2TiO5 e Cu3TiO4. Realizou-se a caracterização dos materiais por meio das técnicas de DRX, DSC, TGA, MEV/EDS, DRS, PLS e Fisissorção de N2. Os resultados obtidos confirmaram a formação dos materiais, sugerindo a criação de heteroestruturas do tipo PN para as amostras contendo Fe e a formação de fase dopada rutilo Cu para as contendo Cu. A atividade fotocatalítica foi avaliada em teste de desempenho realizado em sistema reacional construído na execução do trabalho. Os testes permitiram identificar resultados preliminares promissores de atividade fotocatalítica para as amostras contendo Fe em sua estrutura, que demonstraram uma significativa atividade fotocatalítica no espectro Visível. / [en] In recent years many efforts have been made to obtain materials capable of efficiently exploiting the potential of solar energy conversion. In particular, the generation of fuels by photocatalysis retains great interest due to its intrinsic properties of promoting up-hill reactions, with a positive free energy variation, allowing its storage in chemical compounds. The efficiency of these processes, however, is usually limited by the photoactivation of main photocatalysts in UV spectrum, wasting much of the solar energy present in visible spectrum. This work investigates the influence on photoactivation performance of heterojunctions with Fe and Cu titanate grown on TiO2 for H2 gas production under Visible light by water-splitting. The samples were prepared according route by wet impregnation followed by post-heating treatment, where metal oxides were formed on TiO2 particles surface with subsequent interdiffusion and formation of ternary phases of Fe2TiO5 e Cu3TiO4. The materials were characterized by DRX, DSC, TGA, MEV / EDS, DRS, PLS and N2 Physisorption techniques. The results confirmed the materials sucessful preparation, suggesting the formation of PN-type heterostructures for Fe-containing samples and a rutile-Cu doped phase for Cu-containing samples. The photocatalytic activity was evaluated in a performance test using a photoreactor system built in as part of this work. The tests allowed to identify promising preliminary results for Fe-containing samples, which demonstrated a significant photocatalytic activity in the Visible spectrum.

Um filme polimérico utilizado na fabricação de curativos adesivos não perfurados deve ter baixo módulo de elasticidade e boa permeabilidade ao vapor d\' água. O baixo módulo de elasticidade garante sensação de maior conforto do produto em contato com a pele quando a pessoa que o está utilizando movimenta a parte do corpo sobre a qual está aplicado o curativo, principalmente a região das articulações, como joelhos e cotovelos. A importância de uma boa permeabilidade ao vapor d\' água está relacionada, principalmente em curativos não perfurados, ao fato de que a pele perde água constantemente e, se o filme polimérico não permitir a saída dessa água ao meio ambiente, ocorrerá um fenômeno denominado maceração, que é a sensibilização excessiva da pele, causada pela hiper hidratação da mesma. O presente trabalho apresenta um estudo da permeabilidade ao vapor d\' água, bem como a caracterização vibracional e térmica de um filme polimérico constituído por três polímeros diferentes, desenvolvido para substituir a poliuretana utilizada atualmente na produção de curativos adesivos não perfurados, com custo inferior. Os polímeros que constituem o filme foram caracterizados separadamente e alguns resultados obtidos, como Tm e a estrutura química dos polímeros Lotader® e Lotryl® foram comparados aos dados fornecidos pelo fabricante. Verificou-se que as propriedades de módulo de elasticidade e permeabilidade ao vapor d\' água do filme desenvolvido são inferiores às da poliuretana inviabilizando a substituição. Entretanto, o trabalho proporcionou um melhor entendimento dos fatores que influenciam o módulo de elasticidade e a permeabilidade do novo material ao vapor d\' água. / A polymeric film must have low elasticity modulus and good water vapor permeation to be used in the production of non perforated adhesive tapes. Low modulus is desirable to provide comfort sensation as the consumer moves the part of his or her body in which the tape is applied on, mainly in the articulations regions, as elbows and knees. The importance of good water vapor permeation is related, mainly in the case of non perforated adhesive tapes with the continuous loss of water by the skin. If the film does not allow the release of the water continuously lost by the skin to the environment, the skin will become very sensitiveness as a result of over hydration. This work presents a study of water permeability and a thermal and vibrational characterization of a polymeric film composed of three different polymers developed to replace the adhesive not perforated polyurethane tape providing lower cost. Besides characterization a test of Water Vapor Transmission Rate (WVTR) was performed. Each polymer present in the film composition was analyzed and the results as Tm and chemical structure of Lotader® e Lotryl® were compared with the producer data. It was verified that the properties of elasticity modulus and water vapor permeability of the new material developed are worse than polyurethane so the substitution can not be performed. However, the work provided a better understanding of the factors that influences the elasticity modulus and water vapor permeability of the new material.

Orientador: Antonio Jose Ramirez Londono / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-21T15:16:14Z (GMT). No. of bitstreams: 1 Santos_TiagoFelipedeAbreu_D.pdf: 110699747 bytes, checksum: 6759b8c1d313c0a5ec2220e3fd107447 (MD5) Previous issue date: 2012 / Resumo: Juntas consolidadas a topo com penetração completa, livres de defeitos, foram obtidas usando a técnica de soldagem por atrito com pino não consumível em chapas de 6 mm de espessura para os aços inoxidáveis duplex UNS S32101 e S32205 e os superduplex UNS S32750 e S32760. Testes de dobramento de raiz indicaram a penetração completa e a ausência de trincas bem como inspeção por líquido penetrante. A penetração completa foi atingida quando o aporte energético aumentou de 0,89 kJ/mm para 1,43 kJ/mm. Os testes de tração na junta soldada evidenciaram a falha no MB e o aumento da resistência mecânica da junta associada à uma boa ductilidade, exceto para o UNS S32760. Mapas de dureza mostraram o aumento da dureza em toda junta soldada em relação ao metal de base. Avaliação microestrutural mostrou um pronunciado refinamento do tamanho de grão médio de ambas as fases (ferrita e austenita) na junta soldada para os materiais estudados. A avaliação por microscopia de transmissão indicou a evolução de arranjos celulares formando contornos de grão na ferrita corroborando o mecanismo de recuperação e rescristalização dinâmica contínua. Análise por meio da técnica de EBSD mostrou elevada fração de contornos de grão do tipo 'sigma' na 'gama' indicando a recristalização dinâmica descontínua desta fase. Os AID S32205, S32750, S32760 mostraram sutis alterações na resistência à corrosão para meios com diferentes concentrações de cloretos (3,5% NaCl e 1 M NaCl). Porém, para concentrações mais altas o AISD S32760 exibiu importante decréscimo de resistência a corrosão. Este comportamento foi associado à maior fração de ferrita e a precipitação do nitreto de cromo na junta soldada. O AID S32101 mostrou diminuição da resistência à corrosão na condição como soldado / Abstract: Fully consolidated and full penetration butt joints were produced using friction stir welding (FSW) on 6 mm thick plates of UNS S32101 lean duplex stainless steel (LDSS), S32205 duplex stainless steel (DSS) and S32750 and S32760 superduplex stainless steels (SDSS) with heat input of 1.43 kJ/mm. Liquid penetrant inspection showed the full penetration obtained in the welded joints which was corroborated with the bending tests. Transverse tensile tests of the welded joints failed at the base metal revealing an overmatching weld metal. Moreover, longitudinal tensile tests of the welded joints presented an increase of the yield and tensile strength for all joints together with the elongation, but for UNS S32760, which showed a ductility reduction. Microhardness revealed a hardness increase for all the joints, while the SDSSs presented a more homogeneous hardeness areas of joint. Microstructural evaluation indicated a pronounced grain refinement in the welded joints for all the studied materials achieving down to 1 ?m grain size. Transmission electron microscopy and EBSD indicated dislocation cells evolving towards grain boundaries that corroborates the occurrence of dynamic recovery followed by continuous dynamic recrystallization for ferrite. Austenite exhibited high fraction of high angle grain bondaries associated with 'sigma' boundaries indicating the discontinuous dynamic recrystallization. DSS UNS S32205, SDSS UNS S32750, and S32760 showed good corrosion behavior for 3.5% NaCl and 1 M NaCl environments. However, with the increase of chlorides concentrations, the SDSS UNS S32760 exhibited strong decrease of corrosion performance. This behavior was associated with a combination of high ferrite fraction and chromium nitride precipitation. DSS S32101 exhibited a decrease of corrosion performance when welded / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

Dans l’industrie automobile, le véhicule électrique séduit de plus en plus de clients. Ce qui limite sa progression dans le marché est son manque d’autonomie. Une des solutions permettant d’augmenter l’autonomie d’un véhicule est de réduire sa masse en modifiant la géométrie des pièces et les matériaux utilisés. Cependant, de tels changements peuvent avoir des impacts sur la CEM du véhicule.Les travaux de cette thèse portent sur l’étude de l’allègement du blindage des batteries de traction pour véhicule électrique du point de vue de la CEM. Plusieurs méthodes de caractérisation de matériaux sont mises en place dans ce document. Une méthode innovante reposant sur l’utilisation d’une cellule TEM ou d’une stripline a été développée durant ces travaux de thèse, elle permet de mesurer la permittivité relative complexe d’un matériau diélectrique inconnu entre 1 kHz et 1 GHz. Les propriétés électromagnétiques ainsi mesurées sont insérées dans des modèles numériques 3D. Les méthodes numériques adaptées à ce type d’étude sont les différences finies dans le domaine temporel et la méthode des moments. L’étude du rayonnement de la batterie a été effectuée grâce à une maquette à l’échelle ½ en chambre semi-anéchoïque et en chambre réverbérante à brassage de mode selon des montages normatifs. Des configurations plus complexes ont ensuite été étudiées en tenant compte de l’intégration du pack-batterie dans le véhicule. / In automotive industry, electric vehicle is becoming more and more attractive for car buyers. The market penetration of electric vehicle is limited by its short range. One of the solutions to increase the range is to lower the weight of the vehicle by modifying the geometry or the material composition. Nevertheless, such changes may have consequences on the EMC of the vehicle.The work of this thesis concern the study of weight reduction of the battery shield from an EMC point of view. Several methods for materials characterization are set in this document. A method which uses a TEM cell or a stripline has been designed during this thesis to measure the complex relative permittivity of an unknown dielectric material. Then, the measured properties are inserted into numerical 3D models. The numerical techniques that fit this study are the finite differences in time domain and the method of moments. The study of radiated electromagnetic field from a battery has been performed thanks to a ½ scale model in semi anechoic chamber and mode-stirred reverberation chamber according to standard setups. More complex configurations were studied taking into account the integration of the battery-pack into the vehicle.

<div>Metal-zeolites are promising materials for passive adsorber technologies for the abatement of nitrogen oxides (NOx, x = 1,2) and aldehydes during low-temperature operation in automotive exhaust aftertreatment systems. The aqueous-phase exchange processes used commonly to prepare metal-zeolites typically require mononuclear, transition metal complexes to diffuse within intrazeolite pore networks with their solvation shells and replace extra framework cations of higher chemical potential. When metal complexes are larger than the zeolite pore-limiting diameter, this imposes intracrystalline transport restrictions; thus, complexes and agglomerates tend to preferentially deposit near the surfaces of crystallites, requiring post-synthetic treatments to disperse metal species more uniformly throughout zeolite crystallites via solid-state ion-exchange processes. Here, we address the influence of post-synthetic gas treatments and zeolite material properties on the structural interconversion and exchange of extra framework Pd in CHA zeolites with a focus on the thermodynamic, kinetic, and mechanistic factors that dictate the Pd site structures and spatial distributions that form.<br></div><div><br></div><div>Pd-amine complexes introduced via incipient wetness impregnation on CHA zeolites were found to preferentially site near crystallite surfaces. Post-synthetic treatments in flowing air results in Pd-amine decomposition and agglomeration to metallic Pd0and supersequent oxidation to PdO, before converting to mononuclear Pd²⁺cations through an Ostwald ripening mechanism at high temperatures (>550 K). Progressively higher air treatment temperatures (up to 1023 K) were found to (1) thermodynamically favor the formation of mononu-clear Pd²⁺cations relative to agglomerated PdO particles, (2) increase the apparent rate of structural interconversion to mononuclear Pd²⁺, and (3) facilitate longer-range mobility of molecular intermediates involved in Ostwald ripening processes that allow Pd cations to form deeper within zeolite crystallites to form more uniformly dispersed Pd-zeolite materials. Additionally, the controlled synthetic variation of the atomic arrangement of 1 or 2Al sites in the 6-membered ring of CHA was used to show a thermodynamic preference to form mononuclear Pd2+cations charge-compensated by 2 Al sites over [PdOH]⁺complexes at 1 Al site. Colloidal Pd nanoparticle syntheses and deposition methods were used to prepare monodisperse Pd-CHA materials to isolate the effects of Pd particle size on structuralinterconversion to mononuclear Pd²⁺under a range of external environments. Consistent with computational thermodynamic predictions, smaller Pd particle sizes favor structural interconversion to mononuclear Pd²⁺under high-temperature air treatments (598–973 K),while adding H2O to the air stream inhibits the thermodynamics but not the kinetics of mononuclear Pd²⁺formation, demonstrating that water vapor in exhaust streams may be deleterious to the long-term stability of Pd-zeolite materials for passive NOx adsorption.<br></div><div><br></div><div>The influence of metal-zeolite material properties on the adsorption, desorption, and conversion of formaldehyde, a government-regulated automotive pollutant, under realistic conditions was investigated to identify beneficial material properties for this emerging application in mobile engine pollution abatement. A suite of Beta zeolite materials was synthesized with varied adsorption site identity (Brønsted acid, Lewis acid, silanol groups, and extra framework metal oxide) and bulk site densities. All materials stored formaldehyde and converted a large fraction of formaldehyde to more environmentally benign CO and CO₂, demonstrating the efficacy of silanol defects and zeolitic supports for the storage of formaldehyde. Sn-containing zeotypes, containing either Lewis acidic framework Sn sites or extra framework SnO_x particles, resulted in the greatest selectivity to CO and CO₂ formed during formaldehyde desorption, suggests that Sn species are a beneficial component in metal-zeolite formulations for the abatement of formaldehyde in automotive exhaust streams.<br></div><div><br></div><div>This work demonstrates how combining precise synthesis of metal-zeolites of varied bulk and atomic properties with site-specific characterization and titration methods enables systematically disentangling the influence of separate material properties (e.g., Pd particle size, zeolite framework Al arrangement, silanol density, heteroatom identify) and external environment on changes to metal structure, speciation, and oxidation state. This approach provides thermodynamic, kinetic, and mechanistic insights into the factors that influence metal re-structuring under the practical conditions encountered in automotive exhaust after treatment applications and guidance for materials design and treatment strategies to form desired metal structures during synthesis and after regeneration protocols.<br></div>