Bulletin of the American Physical Society
Spring 2017 Meeting of the APS New England Section, held jointly with NanoWorcester
Volume 62, Number 5
Friday–Saturday, April 14–15, 2017; Worcester, Massachusetts
Session D6: Nanomaterials and Nanoparticles |
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Chair: Gang Han, UMass Medical School Room: Olin Hall 223 |
Saturday, April 15, 2017 10:15AM - 10:20AM |
D6.00001: Opening Remarks |
Saturday, April 15, 2017 10:20AM - 10:40AM |
D6.00002: Mapping the Modulus of Organic Matter in Stiff Nano-Composites across the Thermal Maturity Scale Nancy Burnham, Shannon Eichmann, David Jacobi, Mohammad Haque Hydrocarbons power modern economies, and energy companies are on mission to provide an inexpensive supply [1]. Most characterization of source rocks has been traditional, bulk, and destructive. Here, we characterize the organic matter in source rocks using non-destructive Raman spectroscopy and modulus mapping by atomic force microscopy [2]. Mapping the stiff organic matter in these nano-composites is challenging; the methods and assumptions will be explained. Subtle shifts in the Raman peaks are linked to sample maturity (i.e. propensity to yield oil and gas), yet no direct correlation between elastic modulus and maturity was found. However, intriguing variations across individual samples is an area of continued interest for future work. The use of micro- and nano-characterization techniques should contribute to the science behind ensuring a steady supply of the world's power. [1] M. Marder et al., \textit{Physics Today} \textbf{69}(7), 46 (2016) [2] S.L. Eichmann et al., \textit{submitted }(2017) [Preview Abstract] |
Saturday, April 15, 2017 10:40AM - 11:00AM |
D6.00003: Gas and vapor dependent photoluminescence changes of zinc oxide nanoparticles Sol Kim, R. M. Dulanga S. Somaratne, Sandip K. Sengupta, James E. Whitten Nanoparticulate zinc oxide (ZnO) excited by 320-340 nm light consists of a sharp ultraviolet and a broad visible emission peak. The former originates from excitonic recombination, and the latter appears due to surface defects, including oxygen vacancies. Since visible emission of ZnO nanoparticles is affected by surface states and morphology, adsorption of gases on ZnO may be monitored by measuring changes in photoluminescence (PL). In this presentation, we report recent experimental measurements in PL changes of ZnO nanoparticles upon exposure to various gases and vapors. Possible adsorption mechanisms are suggested aided by thermal gravimetric analysis and X-ray photoelectron spectroscopy. Density functional theory (DFT) calculations on zinc oxide clusters with co-adsorbed surface hydroxyls also have been studied to understand the bonding of adsorption on ZnO nanoparticles. In the case of reversible adsorption, the PL changes may be explained by the transfer of electrons to or from the conduction band, and these may directly affect excitonic recombination. For irreversible chemisorption, it is found that surface hydroxyls or lattice oxygen atoms play a key role in the surface reaction. [Preview Abstract] |
Saturday, April 15, 2017 11:00AM - 11:20AM |
D6.00004: Developing Iridium-based Alloys as Effective Catalysts for Direct Ethanol Fuel Cells Lida Namin, Aaron Deskins, Koretaka Yuge Fuel cells enable the conversion of different chemicals directly into electrical energy, and are much more efficient than conventional combustion engines. Direct ethanol fuel cells (DEFCs) use ethanol as a fuel source. However, DEFCs are not commercialized due to the lack of an efficient catalyst. Iridium alloys are promising catalysts as they possess high catalytic activity and are much cheaper than platinum, the traditional fuel cell catalyst. Synthesizing all possible alloys experimentally is a burdensome task which is not economically feasible. As a result, in this study we have developed realistic atomic models of iridium alloys in DEFCs. Since density functional theory (DFT) methods are limited by finite computation power, we used the combination of DFT with statistical physics methods, specifically, cluster expansion (CE). Our results show how theoretical methods can advance alloy development by predicting stable structures of iridium alloys. [Preview Abstract] |
Saturday, April 15, 2017 11:20AM - 11:40AM |
D6.00005: Electrospun separators for structural battery applications Wisawat Keaswejjareansuk, Jianyu Liang Lithium-ion battery (LIB) has been utilized in variety applications as energy source. Structural battery is a new approach that employs multifunctional material concept to use LIB with load-bearing capability to minimize the weight of the complete energy consumption system and maximize the efficiency. LIB usually consists of cathode, polymeric separator, and anode; in face, the separator has been known as the weakest part of conventional LIB. This work aims at creating electrospun (ES) polymer membranes (at room temperature) with nanostructures as next generation LIB separator with improved thermal resistance and mechanical properties. ES is simple, flexible also cost-effective at all scales. The ES employs the electrostatic force to control the production of nanofibers from polymer solutions. Solution and process parameters, such as type of polymer, solution concentration, acceleration voltage, and solution feed rate, have been studied to achieve the desirable membrane properties. Many characteristics of electrospun polymer membrane would affect the performance of it as the separator in LIB, including surface morphology, microstructure, thermal stability, mechanical property, and electrochemical performance. In this study scanning electron microscopy, dynamic scanning calorimetry, tensile testing and electrochemical testing have been used to characterize the ES membranes. Design of experiments techniques has also been utilized to optimize the parameters in creating separator for structural batteries. [Preview Abstract] |
Saturday, April 15, 2017 11:40AM - 12:00PM |
D6.00006: Photoanode with enhanced performance achieved by coating BiVO4 onto ZnO-templated Sb-doped SnO2 nanotube scaffold Lite Zhou, Yang Yang, Jing Zhang, Pratap Rao The performance of BiVO4 photoanodes, especially under front-side illumination, is limited by the modest charge transport properties of BiVO4. Core/shell nanostructures consisting of BiVO4 coated onto a conductive scaffold are a promising route to improving the performance of BiVO4-based photoanodes. Here, we investigate photoanodes composed of thin and uniform layers of BiVO4 particles coated onto Sb doped SnO2 (Sb:SnO2) nanotube arrays that were synthesized using a sacrificial ZnO template with controllable length and packing density. We demonstrate a new record for the product of light absorption and charge separation efficiencies ($\eta $abs \texttimes $\eta $sep) of \textasciitilde 57.3{\%} and 58.5{\%} under front- and back-side illumination, respectively, at 0.6 VRHE. Moreover, both of these high $\eta $abs \texttimes $\eta $sep efficiencies are achieved without any extra treatment or intentional doping in BiVO4. These results indicate that integration of Sb:SnO2 nanotube cores with other successful strategies such as doping and hydrogen treatment can increase the performance of BiVO4 and related semiconductors closer to their theoretical potential. [Preview Abstract] |
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