Open Access Publications

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https://udspace.udel.edu/handle/19716/29832
Open access publications by faculty, postdocs, and graduate students in the Department of Chemical and Biomolecular Engineering

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Browsing Open Access Publications by Subject "affordable and clean energy"

Now showing 1 - 5 of 5
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    Bioderived silicon nano-quills: synthesis, structure and performance in lithium-ion battery anodes
    (Green Chemistry, 2024-03-12) Chen, Nancy; Sabet, Morteza; Sapkota, Nawraj; Parekh, Mihir; Chiluwal, Shailendra; Koehler, Kelliann; Clemons, Craig M.; Ding, Yi; Rao, Apparao M.; Pilla, Srikanth
    Cellulose nanocrystals (CNCs) are bioderived one-dimensional species with versatile surface chemistry and unique self-assembling behavior in aqueous solutions. This work presents a scientific approach to leverage these characteristics for creating CNC network templates and processing them to engineer a novel silicon (Si)-based material called silicon nano-quill (SiNQ) for energy storage applications. The SiNQ structure possesses a porous, tubular morphology with a substantial ability to store lithium ions while maintaining its structural integrity. The presence of Si suboxides in the SiNQ structure is demonstrated to be crucial for realizing a stable cycling performance. One of the defining attributes of SiNQ is its water dispersibility due to Si–H surface bonds, promoting water-based Si-graphite electrode manufacturing with environmental and economic benefits. The incorporation of only 17 wt% SiNQ enhances the capacity of graphitic anodes by ∼2.5 times. An initial coulombic efficiency of 97.5% is achieved by employing a versatile pre-lithiation. The SiNQ-graphite anodes with high active loading, when subjected to accelerated charging/discharging conditions at 5.4 mA cm−2, exhibit stable cycling stability up to 500 cycles and average coulombic efficiency of >99%. A generalized physics-based cyclic voltammetry model is presented to explain the remarkable behavior of SiNQs under fast-charging conditions.
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    Cycloaddition–dehydration continuous flow chemistry for renewable para-xylene production from 2,5-dimethylfuran and ethylene over phosphorous-decorated zeolite beta
    (Green Chemistry, 2024-07-03) Wang, Zhaoxing; Goculdas, Tejas; Hsiao, Yung Wei; Fan, Wei; Vlachos, Dionisios G.
    Continuous manufacturing of platform chemicals from lignocellulose is highly desirable for a fossil fuel independent future. We demonstrate highly selective production of para-xylene (pX) from ethylene and 2,5-dimethylfuran (DMF) in a packed bed microreactor using phosphorous-decorated zeolite beta (P-BEA), with pX selectivity up to 97% at 80% DMF conversion. We map the effect of reactor temperature, space velocity, concentration, gas-to-liquid ratio, and process pressure. Time-on-stream (TOS) and in situ regeneration studies show minimal productivity degradation over ∼5 h TOS and full productivity restoration upon regeneration for multiple cycles. Most non-selective Brønsted acidity occurs at low TOS and is attributed to the remaining trace Al bridge site. External mass transfer limitations are implicated at low space velocities. We combine the TOS data with NMR, XRD, and Raman to develop structure–performance insights into the catalyst behavior. A comparison with mesoporous P-supported materials illustrates that P-BEA is an excellent catalyst for size selectivity and long-term stability.
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    Direct Integration of Strained-Pt Catalysts into Proton-Exchange-Membrane Fuel Cells with Atomic Layer Deposition
    (Advanced Materials, 2021-07-28) Xu, Shicheng; Wang, Zhaoxuan; Dull, Sam; Liu, Yunzhi; Lee, Dong Un; Pacheco, Juan S. Lezama; Orazov, Marat; Vullum, Per Erik; Dadlani, Anup Lal; Vinogradova, Olga; Schindler, Peter; Tam, Qizhan; Schladt, Thomas D.; Mueller, Jonathan E.; Kirsch, Sebastian; Huebner, Gerold; Higgins, Drew; Torgersen, Jan; Viswanathan, Venkatasubramanian; Jaramillo, Thomas Francisco; Prinz, Fritz B.
    The design and fabrication of lattice-strained platinum catalysts achieved by removing a soluble core from a platinum shell synthesized via atomic layer deposition, is reported. The remarkable catalytic performance for the oxygen reduction reaction (ORR), measured in both half-cell and full-cell configurations, is attributed to the observed lattice strain. By further optimizing the nanoparticle geometry and ionomer/carbon interactions, mass activity close to 0.8 A mgPt−1 @0.9 V iR-free is achievable in the membrane electrode assembly. Nevertheless, active catalysts with high ORR activity do not necessarily lead to high performance in the high-current-density (HCD) region. More attention shall be directed toward HCD performance for enabling high-power-density hydrogen fuel cells.
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    Study of Cathode Gas Diffusion Architecture for Improved Oxygen Transport in Hydroxide Exchange Membrane Fuel Cells
    (Journal of The Electrochemical Society, 2022-05-04) Weiss, Catherine M.; Setzler, Brian P.; Yan, Yushan
    The high pH environment in hydroxide exchange membrane fuel cells (HEMFCs) has the potential to reach lower costs than the current proton exchange membrane fuel cells (PEMFCs), the incumbent technology. A significant difference between HEMFCs and PEMFCs is the location of water production within the cell. In PEMFCs, the water is produced on the cathode, limiting oxygen transport. In HEMFCs, the water is produced on the anode where the fuel is pure hydrogen. This allows the cathode to be optimized for oxygen transport without the presence of excess liquid water. Limiting current analysis, a technique previously used in PEMFCs, is adopted in HEMFCs to evaluate the oxygen mass transport resistances for different sections of the cathode. Through elimination of the microporous layer (MPL), gas diffusion layer (GDL), and traditional flow field and using porous nickel foam for gas distribution, the transport resistance at an operating condition of 150 kPa(g) and with the cell temperature at 80 °C was decreased from 112 s m−1 to 48 s m−1, effectively halved. The optimal configuration for performance was found with Ni foam and a GDL, eliminating the MPL and traditional flow field, which vastly improved oxygen transport while maintaining adequate electrical contact with the cathode catalyst layer.
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    Sustainable Aviation Fuel Molecules from (Hemi)Cellulose: Computational Insights into Synthesis Routes, Fuel Properties, and Process Chemistry Metrics
    (ACS Sustainable Chemistry and Engineering, 2024-08-13) Chang, Chin-Fei; Paragian, Kristin; Sadula, Sunitha; Rangarajan, Srinivas; Vlachos, Dionisios G.
    Production of sustainable aviation fuels (SAFs) can significantly reduce the aviation industry’s carbon footprint. Current pathways that produce SAFs in significant volumes from ethanol and fatty acids can be costly, have a relatively high carbon intensity (CI), and impose sustainability challenges. There is a need for a diversified approach to reduce costs and utilize more sustainable feedstocks effectively. Here, we map out catalytic synthesis routes to convert furanics derived from the (hemi)cellulosic biomass to alkanes and cycloalkanes using automated network generation with RING and semiempirical thermochemistry calculations. We find >100 energy-dense C8–C16 alkane and cycloalkane SAF candidates over 300 synthesis routes; the top three are 2-methyl heptane, ethyl cyclohexane, and propyl cyclohexane, although these are relatively short. The shortest, least endothermic process chemistry involves C–C coupling, oxygen removal, and hydrogen addition, with dehydracyclization of the heterocyclic oxygens in the furan ring being the most endothermic step. The global warming potential due to hydrogen use and byproduct CO2 is typically 0.7–1 kg CO2/kg SAF product; the least CO2 emitting routes entail making larger molecules with fewer ketonization, hydrogenation, and hydrodeoxygenation steps. The large number of SAF candidates highlights the rich potential of furanics as a source of SAF molecules. However, the structural dissimilarity between reactants and target products precludes pathways with fewer than six synthetic steps, thus necessitating intensified processes, integrating multiple reaction steps in multifunctional catalytic reactors.
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