Publications by authors named "WEITZNER S"

Electrochemical CO reduction is a promising technology for replacing fossil fuel feedstocks in the chemical industry but further improvements in catalyst selectivity need to be made. So far, only copper-based catalysts have shown efficient conversion of CO into the desired multi-carbon (C) products. This work explores Cu-based dilute alloys to systematically tune the energy landscape of CO electrolysis toward C products.

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Naturally occurring coatings on aluminum metal, such as its oxide or hydroxide, serve to protect the material from corrosion. Understanding the conditions under which these coatings mechanically fail is therefore expected to be an important aspect of predictive models for aluminum component lifetimes. To this end, we develop and apply a molecular dynamics (MD) modeling framework for conducting tension tests that is capable of isolating factors governing the mechanical strength as a function of coating chemistry, defect morphology, and variables associated with the loading path.

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The activity and product selectivity of electrocatalysts for reactions like the carbon dioxide reduction reaction (CORR) are intimately dependent on the catalyst's structure and composition. While engineering catalytic surfaces can improve performance, discovering the key sets of rational design principles remains challenging due to limitations in modeling catalyst stability under operating conditions. Herein, we perform first-principles density functional calculations adopting implicit solvation methods with potential control to study the influence of adsorbates and applied potential on the stability of different facets of model Cu electrocatalysts.

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Bare aluminum metal surfaces are highly reactive, which leads to the spontaneous formation of a protective oxide surface layer. Because many subsequent corrosive processes are mediated by water, the structure and dynamics of water at the oxide interface are anticipated to influence corrosion kinetics. Using molecular dynamics simulations with a reactive force field, we model the behavior of aqueous aluminum metal ions in water adsorbed onto aluminum oxide surfaces across a range of ion concentrations and water film thicknesses corresponding to increasing relative humidity.

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Ionic liquids possess compelling properties and vast chemical diversity, promising unprecedented performance and tunability for advanced electrochemical applications in catalysis, sensing, and energy storage. However, with broad tunability comes intractable, multidimensional parameter spaces not easily traversed by empirical approaches, limiting both scientific understanding and technological breakthroughs with these novel materials. In this Communication, we propose an extensible figure of merit that co-optimizes key ionic liquid properties, including electrochemical stability window, viscosity, and molecular ion size with respect to pore sizes of nanoporous electrodes typically utilized in electrochemical technologies.

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Article Synopsis
  • Ion (de)hydration is crucial for processes like corrosion and energy storage, but its kinetics are hard to predict using traditional methods.
  • Current approaches rely on static measures like hydration energy, which don't adequately reflect the dynamics of the hydration shell affecting ion transfer rates.
  • This study introduces dynamic metrics from molecular dynamics simulations, providing a better understanding of hydration shell properties and their impact on ion (de)hydration, indicating that dynamic descriptors are essential for accurately describing these processes.
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Cu-based catalysts currently offer the most promising route to actively and selectively produce value-added chemicals via electrochemical reduction of CO (eCOR); yet further improvements are required for their wide-scale deployment in carbon mitigation efforts. Here, we systematically investigate a family of dilute Cu-based alloys to explore their viability as active and selective catalysts for eCOR through a combined theoretical-experimental approach. Using a quantum-classical modeling approach that accounts for dynamic solvation effects, we assess the stability and activity of model single-atom catalysts under eCOR conditions.

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Bridging polymer design with catalyst surface science is a promising direction for tuning and optimizing electrochemical reactors that could impact long-term goals in energy and sustainability. Particularly, the interaction between inorganic catalyst surfaces and organic-based ionomers provides an avenue to both steer reaction selectivity and promote activity. Here, we studied the role of imidazolium-based ionomers for electrocatalytic CO reduction to CO (COR) on Ag surfaces and found that they produce no effect on COR activity yet strongly promote the competing hydrogen evolution reaction (HER).

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Engineering the electrolyte microenvironment represents an attractive route to tuning the selectivity of electrocatalytic reactions beyond catalyst composition and morphology. However, harnessing the full potential of this approach requires understanding the interplay between voltage, electrolyte composition, and adsorbate binding within the electrical double layer, which is absent from the usual theoretical approaches. In this work, we apply a recently developed density functional theory (DFT)-continuum approach based on the effective screening medium method and reference interaction site model (ESM-RISM) to explore electrolyte effects with an enhanced description of the electrochemical interface.

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The catalytic performance of multimetallic electrodes is often attributed to a beneficial combination of ligand, strain, and ensemble effects. Understanding the influence of the electrochemical environment on the stability of the alloy surface structure is thus a crucial component to the design of highly active and durable electrocatalysts. In this work, we study the effects of an applied voltage to electrocatalytic Pd-Au/Au(111) surface alloys in contact with a model continuum electrolyte.

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Purpose: Sinonasal undifferentiated carcinoma (SNUC) is a rare and aggressive malignancy of the paranasal sinuses and nasal cavity. Of the few reported series, most indicate a dismal prognosis. In this report, the clinical presentation, histopathologic criteria used for diagnosis, mode of treatment, and outcome are evaluated in seven patients with SNUC.

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We report 5 cases of simple cyst of the testis, the largest series to date, and review the literature. Included are 2 autopsy cases, a case of a multilocular simple cyst and 1 case treated nonoperatively. Based on our experience, simple cyst of the testis should be suspected particularly in an enlarged but otherwise palpably normal testis.

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Mucormycosis of the nasal cavity and paranasal sinuses is an aggressive, life-threatening condition characterized by fulminant destruction of soft tissues and bone, vascular invasion, and thrombosis. Patients who have this infection generally are immunosuppressed or diabetic. The most effective treatment is immediate surgical debridement of all involved tissue, along with systemic antifungal agents.

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Primary lymphoma of the kidney is extremely rare; most lymphomatous renal masses represent extension from adjacent sites of disease or involvement by generalized disease (4,9,12). Three men and one woman, 45 to 71 years of age, presented with solitary renal masses clinically thought to be renal cell carcinoma. Each experienced abdominal pain, one with hematuria and one with "B" symptoms.

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Cutaneous malignant melanoma sometimes metastasizes to the upper respiratory and digestive tracts. It may cause significant local symptoms such as airway obstruction and dysphagia, and, in some cases, may represent the initial manifestation of disseminated disease. Of the 8,823 patients with cutaneous malignant melanoma seen at The University of Texas-M.

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I have reported three cases of asymptomatic osseous choristoma of the tongue and reviewed the 38 previously reported cases, 80% of which occurred in women and in patients less than 40 years old. Most osseous choristomas are located in the posterior third of the tongue and primarily in the vicinity of the foramen cecum and/or circumvallate papillae. Derivation from a remnant of the cartilaginous matrix of the second and third branchial arches is the favored hypothesis of origin.

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A case of ectopic salivary gland tissue in the submucosa of the rectum adjacent to a hyperplastic polyp is described. The two previously reported cases of ectopic salivary gland tissue in the rectum were different in that ectopic gastric mucosa was also present. The 16 cases of ectopic tissue in the rectum noted in the world medical literature are reviewed.

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We have described a case of multiple metastases in the hypopharynx found at autopsy in a 43-year-old woman with carcinoma of the breast. No symptoms related to the hypopharyngeal lesions were recorded. A metastasis, although rare, should be included in the differential diagnosis of a hypopharyngeal lesion since it may clinically mimic a benign neoplasm or primary carcinoma.

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A case of adenocarcinoma of the prostate in a twenty-seven-year-old man is reported. He responded initially to cobalt radiation to the prostate, but metastases developed subequently and he died thriteen months after the histologic diagnosis was made. Three of the 4 previously documented cases in men below age thirty who also presented with symptoms of obstruction of the lower urinary tract or bone pain died four, five, and twelve months later.

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