Institutional Repository
The UDSpace Institutional Repository collects and disseminates research material from the University of Delaware.
- Faculty, staff, and graduate students can deposit their research material directly into UDSpace. Faculty may use UDSpace to fulfill the University of Delaware Faculty Senate Open Access Resolution, and in many cases may use it to fulfill open access requirements from grant funding agencies.
- Departments can use UDSpace to publish or distribute their working papers, technical reports, or other research material.
- UDSpace also includes all doctoral dissertations from winter 2014 forward, and all master's theses from fall 2009 forward.
To learn more about UDSpace, and how you can make your research openly accessible to the public, visit our UDSpace Policies website.
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Recent Submissions
Linearly scaled-up plasma-water biphasic DBD microreactors: Application to hydrogen peroxide synthesis and water decontamination
(ACS Sustainable Chemistry & Engineering, 2025-11-24) Camelia, Fabio; Dimitrakellisa, Panagiotis; Vlachosa, Dionisios G.
We previously demonstrated that a modular biphasic liquid water/helium plasma reactor can efficiently produce hydrogen peroxide (H2O2). Here we demonstrate that by increasing the reactor length and thus the residence time or the applied plasma power, we can increase the outlet H2O2 concentration in the aqueous phase (an example of 39 mM is showcased) while using an argon plasma. By introducing spatially resolved optical emission spectroscopy (OES), we reveal an increasing water-produced ·OH radical concentration along the tubular reactor and correlate the ·OH production with the H2O2 concentration. High peroxide concentrations achieved through a straightforward linear reactor scale-up are suitable for green partial oxidation reactions and biochemical and environmental decontamination. This potential is exemplified by showcasing the complete and ultrafast continuous flow decolorization of an aqueous solution of highly concentrated (300 mg L–1) methylene blue (MB).
Designing Biochemical Visual Literacy Assessments: Insights from Classroom Testing and Student Interviews
(Journal of Chemical Education, 2024-11-24) Procko, Kristen; Beckham, Josh; Acevedo, Roderico; Agrawal, Swati; Austin, Shane; Burch, Charmita; Engelman, Shelly; Fox, Kristin; Genova, Lauren; Mertz, Pamela; Mitton-Fry, Rachel; Vardar-Ulu, Didem
A critical skill that biochemistry students must develop is the interpretation of molecular images, ranging from macromolecular representations to the chemical structures of the building blocks that comprise them. Such analysis requires biomolecular visual literacy, which is not often explicitly taught, and can be challenging for instructors to assess. In this work, we examine student responses to assessments designed to probe biomolecular visual literacy. Analysis of sets of assessments with classical test theory indicates that items which have undergone an iterative validation process, including expert review, perform well in classroom testing. However, the evaluation of multiple-choice and multiple-select assessment items based on classroom testing alone has limitations. Therefore, semistructured student interviews were used to explore student approaches to molecular visualization problem solving. Qualitative analysis of interview transcripts identified several common strategies among students when solving image-based questions, including relying on color in the images to answer questions, drawing on familiar terminology in the prompt, and using process-of-elimination to identify the best answer. Image complexity was identified as a common challenge for students. Instructors can craft more effective assessments by paying careful attention to the use of color in images, using terminology students are familiar with, carefully creating distractors, and using images with complexity appropriate to the learner level. This work underscores the importance of the student perspective in the design of assessments used by educators to evaluate learning.
Raman Evidence for the Mechanism of Enhanced C–C Coupling during CO2RR on CuSnx Bimetallic Electrocatalysts at Dilute Sn Levels
(Journal of The Electrochemical Society, 2025-12-01) Mishra, Mritunjay; Obetta, Emmanuel; Dauda, Monsuru Olatunji; Flake, John; Yao, Koffi P. C.
The electrochemical carbon dioxide reduction reaction (CO2RR) presents a promising method for converting CO2 into valuable fuels and chemicals, but requires electrocatalysts with high selectivity. Here, we investigate CuSnx catalysts with systematically varied Sn contents to elucidate composition-selectivity relationships. Electrolyzer testing reveals that 3%Sn-doped Cu electrocatalyst selectively produces C2 products, primarily ethanol and ethylene, whereas higher Sn contents (>3%) shift selectivity toward C1 products, predominantly formic acid. X-ray photoelectron spectroscopy suggests the coexistence in similar proportions of near neutral (Cu) and partial positive (Cuδ+) sites at low Sn contents. On the other hand, at high Sn contents, surface Cu skews towards monolithically Cu2+ states. From In-situ surface-enhanced Raman spectroscopy, at 3%Sn, abundant *COOH absorbed via carbon is detected that leads to detected high *CO coverage with electrophilicity imbalance from absorbing at Cu and Cuδ+. Two electronically dissimilar *COs then promote *CO*CO dimerization favoring C2 products. At 50% and 80% Sn, HCOO* intermediate adsorbed via oxygen is detected instead, leading to formic acid as the major product upon proton transfer. The findings experimentally validate prior computational density functional theory conclusions and provide empirical insight into the role of Sn doping in tuning the catalytic behavior of Cu for CO2RR.
2025, 49th Issue, part 2
(Newark, Del.: Chesapeake Pub. Corp., 2025-12-05) Newark post
2025, 49th Issue, part 1
(Newark, Del.: Chesapeake Pub. Corp., 2025-12-05) Newark post