bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Keynote) The Use of Polyoxometallates in Proton Conducting Membranes for Electrochemical Energy Conversion
Authors: Herring Andrew M. , Kuo Mei-Chen 
Published: February 2020

Heteropoly acids (HPAs), a subclass of the polyoxometalates, are a class of proton conducting radical activating or decomposing molecules. Several types of HPAs have demonstrated the ability to improve membrane chemical stability and proton conductivity through polymer blends, but they still suffer from migration of the HPA species and only result in marginal gains. A method of covalent bonding HPAs to carbon in the catalyst layer has also shown some improvements in chemical stability, but chemical degradation mitigation within the membrane is needed. Our group has developed two membrane platforms with HPAs covalently attached and immobilized within a polymer membrane, serving as the proton conducting acid. More recently, the outstanding chemical stability of one of these platforms has been demonstrated, however, the stability demonstrated in this study was criticized for using rather thick, 80 µm membranes in sub-scale fuel cells.
In a recent study a 50 cm2 fuel cell was fabricated using a thin, 25 µm membrane with covalently attached silicotungstic acid, which was subjected to an accelerated stress test for chemical degradation and displayed an OCV decay rate of 520 µV h-1. To the authors knowledge, this is the first reported fuel cell of a larger practical area containing a hybrid HPA film and represents a significant step towards demonstrating this technology on a commercially relevant scale. The resulting data was analyzed to show the loss in OCV is mainly due to an electrical short and not increased reactant gas crossover. This study further analyzes the chemical stability observed in these membranes and proposes a mechanism for radical decomposition. A reaction mechanism is proposed utilizing reactions found in literature as well as density functional theory (DFT) calculations. The main conclusion from this work is that covalently attached HPAs could be more efficient radical scavengers with less susceptibility to migration, accumulation, and leaching when compared to the use of Ce(III) cations.
We have recently realized a method for cleaning these membrane materials, removing many of the impurities formed during synthesis and have also begun to cross-link these material to eliminate swelling and achieve a dimensionally stable films. These much-improved materials show even higher performance in fuel cells and could potentially solve many of the issues associated with the PFSA materials. In addition the HPA functionalized films have advantages in selective low area spec resistant membranes for redox flow batteries with a variety of redox couples. We all shoe that these membranes can facilitate redox flow batteries with labile vanadium substituted HPAs.
(Invited) Nanomaterial-Based Electrochemical Sensors for Environmental, Food Quality, and Medical Applications
Authors: Chen Aicheng , Manikandan Venkatesh , Liu Zhonggang 
Published: February 2020

Electrochemically based methods offer facile and reliable analytical tools, which are desirable for environment monitoring, food safety and quality assessment, and neurotransmitter analysis over conventional analytical techniques. The development of a wide array of nanomaterials has paved the way for their applicability in the design of electrochemically-based sensing devices for medical diagnostics therapeutics, and imaging, energy, the environment, and food safety. The development of nanomaterials-based electrochemical sensors has garnered enormous attention due to their capacity for analytical quantification, high sensitivity and selectivity, real-time monitoring, and ease of use.
The issue of foodborne related illnesses due to additives and contaminants poses a significant challenge to food processing industries. The robust, efficient, economical, and rapid analysis of food additives and contaminants is therefore necessary in order to minimize the risk of public health issues. In this presentation, the synthesis and applications of different nanomaterials for the electrochemical determination of some common additives and contaminants such as hydrazine, caffeic acid, sulfite, and nitrite will be highlighted. In addition, neurotransmitters are molecules that transfer chemical signals between neurons to convey messages for any action conducted by the nervous system. Neurotransmitters are medically important; the detection and analysis of these molecules play vital roles in the diagnosis and treatment of diseases. The recent development and advance on the electrochemical sensing of neurotransmitters such as nitric oxide will be presented. Moreover, mercury has been recognized as a global pollutant because of its widespread presence, and bioaccumulative and toxic nature. The fabrication of the nanoporous gold microelectrode and its application for the sensitive detection of Hg(II) will be briefly discussed.
Low-Cost Colorimetric Textile Gas Sensor for Detection of Hydrogen Sulfide
Authors: Lee Junyeop , Kim Jae Keon , Jung Daewoong 
Published: February 2020

Hydrogen sulfide(H2S) is a highly toxic, corrosive, flammable gas. It is produced from the microbial breakdown of organic matter in the absence of oxygen. H2S also occurs naturally in volcanic gases, hot springs, and industrially in waste water treatment, gas drilling, tanneries, etc. H2S is colorless, and it reacts with metal ions to form metal sulfides, which are insoluble. For example, lead(II) acetate, soluble white crystalline, is converted lead(II) sulfide(PbS) which is black colored insoluble solid when it exposed to H2S. Recently, there has been development in field of semiconducting metal-oxide sensors [1], optical sensors [2], electrochemical sensors [3] to real time, portable detection of H2S. This study aims to use of a cost-effective, easy to fabricate chemical textile sensor for the detection of H2S. Lead(II) acetate was chosen because of its white color crystalline and solubility. It is easy to recognize changes in color after exposure to harmful gas, H2S. Lead(II) acetate printed textile gas sensor demonstrated dark brown color upon exposure to the H2S under 1 ppm whereas no response was observed to other gas and ambient conditions. And the textile gas sensor was placed between a LED and photodiode to readout the electrical signal. Resistance of photodiode was increased with color change (H2S exposure). It can be noted that extremely small concentrations of H2S even under 1 ppm can be recognized and measured by naked eye and photodiode. This textile-based sensor is disposable, cost effective, easy to fabricate, and simple approach to detect H2S.
[1] G. F. Fine et al., “Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring,” Sensors, vol. 10, no. 6, pp. 5469–5502, Jun. 2010.
[2] K. Hayashi, “Optical Chemical Sensor,” IEEJ Trans. Sensors Micromachines, vol. 135, no. 8, pp. 299–304, 2015.
[3] K. E. Kramer, S. L. Rose-Pehrsson, M. H. Hammond, D. Tillett, and H. H. Streckert, “Detection and classification of gaseous sulfur compounds by solid electrolyte cyclic voltammetry of cermet sensor array,” Anal. Chim. Acta, vol. 584, no. 1, pp. 78–88, 2007.

Figure 1
(Invited) Copper(I) Oxide Semiconductor Based Systems for Photoelectrochemical Reduction of Carbon Dioxide
Authors: Kulesza Pawel J. 
Published: February 2020

There has been growing interest in the photoelectrochemical conversion of carbon dioxide (a potent greenhouse gas and a contributor to global climate change) to useful carbon-based fuels or chemicals. The reaction products are of potential importance to energy technology, food research, medical applications and fabrication of plastic materials. Given the fact that the CO2 molecule is very stable, its electroreduction processes are characterized by large over-potentials. It is often postulated that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate. In this respect, the proton availability and its mobility at the photo(electro)chemical interface has to be addressed. On the other hand, competition between such parallel processes as hydrogen evolution and carbon dioxide reduction has also to be considered. By proper combination of certain metal (Au, Ag, Cu) nanoparticles with nonstoichiometric mixed-metal (WO3+ZrO2) selective reduction of CO2 to alcohols is in acid media feasible.
Recently, we have concentrated on the development of hybrid materials by utilizing combination of metal oxide semiconductors thus capable of effective photoelectrochemical reduction of carbon dioxide. For example, the combination of conducting polymers, or titanium (IV) oxide, and copper (I) oxide has been considered before and after sunlight illumination. Application of the hybrid system composed of both above-mentioned oxides resulted in high current densities originating from photoelectrochemical reduction of carbon dioxide mostly to methanol (CH3OH) as demonstrated upon identification of final products. Among important issue is intentional stabilization, activation, and functionalization of the mixed-metal-oxide-based photoelectrochemcal interface toward better long-term performance and selectivity production of small organic molecules (C1-C4) and other chemicals. In this respect, ultra-thin films of conducting polymers (simple or polyoxometallate-derivatized) and supramolecular complexes (with nitrogen containing ligands and certain transition metal sites), sub-monolayers of metals (Cu, Au), networks of noble metal (Au, Ag) nanoparticles or layers of robust bacterial biofilms have been considered.
The photo-biocathode with Cu-containing enzyme has induced the reduction of not only oxygen but carbon dioxide as well, under illuminations with photon energies higher than silicon band gap.
In the presentation, special attention will be paid to mechanistic aspects of electroreduction of carbon dioxide, fabrication and characterization of highly selective and durable semiconductor photoelectrode materials and to importance of the reaction conditions.
(Invited) Anodic TiO2 Nanotube Layers: Efficient Photocatalyst
Authors: Sopha Hanna , Krbal Milos , Ng Siowwoon , Motola Martin , Dvorak Filip , Zazpe Raul , Prikryl Jan , Macak Jan M. 
Published: February 2020

The self-organized TiO2 nanotube layers have attracted considerable scientific and technological interest over the past 13 years motivated by their possible range of applications including photocatalysis, solar cells, hydrogen generation and biomedical uses [1,2]. The synthesis of these 1D TiO2 nanotube layers is carried out by a conventional electrochemical anodization of valve Ti metal sheet.
Among other TiO2 nanomaterials, these nanotube layers stand out due to their directionality, tunability of dimensions, ability to absorb significant amount of incident light and the possibility to utilize nanotube interiors and exteriors for decoration-coating of secondary materials.
One of the most significant applications of TiO2 nanomaterials is photocatalysis, which is very effective to decompose various pollutants (e.g. dyes) and kill bacteria [3,4].
The presentation will focus on the utilization of the nanotube layer for photocatalytic removal of various species in the liquid phase [5, 6] as well as gas phase [7]. We will also show that various secondary materials have a positive influence on photo-electrochemical properties of nanotube layers [8, 9]. Experimental details and some recent photocatalytic results will be presented and discussed.
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(Invited) Garment Integrated Sensors Created Using Reactive Vapor Deposition
Authors: Andrew Trisha L. 
Published: February 2020

Wearable sensors are uniquely suited for personalized health monitoring and activity tracking. In particular, fiber- and fabric-based sensors that can be seamlessly integrated into everyday clothing have the power to create smart garments that can monitor health statistics and alert a wearer to impending medical problems or chemical/biological threats. However, natural fibers and fabrics--which would be the preferred platform for such garment-integrated sensors--are demanding substrates, and printing electronic materials and electrochemically-active sensors onto natural fibers and fabrics is nontrivial. Solution-processed active materials either soak into natural fibers or nonhomogeneously wet their surfaces, thus creating buried/inaccessible active sites or broken conduction pathways, respectively, that prevent isolation of functioning sensors. Further, the rough and disordered structures of fibers and fabrics also attenuate the baseline bulk conductivities of any electronic material, creating troublesome series resistances that are otherwise absent in conventional, glass- or plastic-backed devices.
Our lab uses reactive vapor coating to form conjugated polymer films directly on the surface of any premade garment, prewoven fabric or fiber/yarn, without the need for specialized processing conditions, surface pretreatments, detergents or fixing agents. This feature allows for electronic coatings to be applied at the end of existing, high-throughput textile and garment manufacturing routines, irrespective of dye content or surface finish of the final textile. Further, reactive vapor coating produces conductive materials without any insulating moieties and yields uniform and conformal films on fiber/fabric surfaces that are notably wash- and wear-stable and withstand mechanically-demanding textile manufacturing routines. These unique features mean that rugged and practical textile electronic devices can be created using sewing, weaving or knitting procedures without compromising or otherwise affecting the surface electronic coating.
In this talk, we will highlight selected electronic garments and garment-integrated sensors created by melding reactive vapor deposition with traditional textile manipulation processes, including: (1) smart joint braces for movement/activity sensing; (2) fabric electrodes for bioimpedance spectroscopy; (3) fiber-based radiation monitors; and (4) garment-integrated chemiresistive sensors for detecting selected biomarkers in sweat.
(Invited) Stochastic Sensors As Screening Tools for Fast and Early Detection of Illnesses
Authors: Stefan-van Staden Raluca-Ioana 
Published: February 2020

Fast and early detection of illnesses such cancer, hepatitis and diabetes is extremely important for the life of the patient. Unfortunately, at the moment the standard methods cannot detect very small amounts of the biomarkers needed for early detection of such illnesses.
We proposed a screening method based on stochastic sensors able to perform both qualitative and quantitative determination of panels of biomarkers used in early detection of illnesses such as cancer, diabetes, and hepatitis.
Results obtained for the screening of whole blood, saliva, and urine samples from confirmed will be shown.
Bimetallic−Organic Framework-Derived Hierarchically Porous Co-Zn-N-C As Efficient Catalyst for Acidic Oxygen Reduction Reaction
Authors: Meng Zihan 
Published: February 2020

The development of highly active and cost-efficient electrocatalysts toward oxygen reduction reaction (ORR) is essential for widespread application of polymer electrolyte fuel cell (PEFC). In the present work, hierarchically structured porous Co-Zn-N-C electrocatalyst is prepared by using soft templated bimetallic-organic framework precursors.
The as-synthesized hierarchically porous catalyst presents outstanding ORR onset-potential (0.88 V vs. RHE), half-wave potential (0.78 V vs. RHE), and diffusion limiting current density (5.73 mA cm-2), that is similar to that at commercial Pt/C catalyst in acidic electrolyte. It is found that the hierarchical porous architecture is important for its excellent catalytic activity and further testifies that the hierarchically porous electrocatalyst also exhibits superior single PEFC performance with a power density of 412 mV cm-2.
The present work provides not only a facile and low cost strategy toward the preparation of hierarchically porous materials, but also inspires an approach for enhancing the ORR electrocatalytic activity of MOF-derived materials.
Pulsed Electrodeposition of Si Under Light Illumination in Ionic Liquid
Authors: Watanuki Shuei , Fukunaka Yasuhiro , Homma Takayuki 
Published: February 2020

Electrodeposition of Si has attracted much attention for its possibility to apply various areas such as photovoltaic cells and MEMS. Si thin film can be electrochemically fabricated with precise microstructural control and in a relatively simple process. However, it requires nonaqueous solvents due to very negative reduction potential of Si(IV). Ionic liquids are promising solvents for Si electrodeposition because of its unique characteristics such as nonflammable, non-volatile, and relatively wide electrochemical window. We have reported the electrochemical processing on Si thin films, nanodots, and nanopillars in trimethylhexyl ammonium bis-(trifluorosulfonyl) imide (TMHATFSI) ionic liquid containing SiCl4 as Si precursor [1-3]. Moreover, our recent paper [4] reports relatively smooth and compact Si thin films obtained by applying pulsed deposition, and smoother ones by applying light illumination additionally. Here we present the results of our work in the electrochemical processing of Si thin film with the pulsed potential modulation and light illumination. These experiments were conducted in order to promote the diffusion of precursor and light-assisted electrodeposition respectively. In the preliminary experiments, it turned out that the composition of Si film in pulse potential modulation [4] contained relatively large amount of impurities than the films potentiostatically deposited [3]. This result suggests that the oxidation currents during the rest period of pulse deposition may be partly responsible for such a larger impurity. Then, pulse potential modulation scheduling was further examined. Controlling the potential and current density considerably suppressed oxidation current. The composition of Si thin films was improved to recover to the level of potentiostatic electrodeposition. However, some cracks were still observed the surface. Thus, light illumination only in deposition time was superimposed. As a result, large cracks disappeared, and continuous and relatively smooth Si thin films with relatively low impurity were obtained.
[1] T. Homma, J. Komadina, Y. Nakano, T. Ouchi, T. Akiyoshi, Y. Ishibashi, Y. Nishimura, T. Nishida, and Y. Fukunaka, ECS Trans., 41 (2012) 9.
[2] Y. Ishibashi, T. Akiyoshi, J. Komadina, Y. Fukunaka, T. Homma, ECS Trans., 50 (2012) 117.
[3] Y. Tsuyuki, A. Pham, J. Komadina, Y. Fukunaka, T. Homma, Electrochim. Acta, 183 (2015) 49.
[4] Y. Tsuyuki, H. Takai, Y. Fukunaka, T. Homma, Jpn. J. Appl. Phys. 57 (2018) 08RB11.
Modeling Fermi Levels in Metal Functionalized TiO2 Sensors for Applications in Volatile Organic Biomarker Detection
Authors: McKinnon Lani , Saffary Yalda , Mohanty Swomitra , Prisbrey Keith 
Published: February 2020

There is a large knowledge base of characteristic volatile organic biomarkers (VOBs) that are detectable as a direct result of a particular disease. VOBs can be detected from many sources including patient breath and urine. The fabrication and testing of VOB sensors for the detection of various diseases is the topic of several ongoing projects in our research group. These VOB sensors utilize a highly specific interaction between a known VOB, a metal-functionalized titanium dioxide sensor, and an applied voltage. When designing a novel sensor for a different disease it can be extremely difficult to determine the appropriate components because the correct choice for VOB, metal, and voltage are all of great importance and each component comes with many possible options.
A simplified version of the sensor system has been examined with various combinations of VOBs and metals using modeling software that employs density function theory (DFT). Density functional calculations were performed to calculate the fermi level of TiO2 functionalized with a group of metals of different valency including Co(III), Ni(II), Fe(II), and Cu(I). The fermi level was then determined for the selected system in the presence of a known VOB. For a potential pneumonia breath sensor these VOBs included heptane, acrolein, and ethylbenzene. The more negative the fermi level became when the metal-functionalized titanium dioxide was in the presence of a particular VOB, the better the sensor was predicted to respond. Promising systems were then tested for selectivity by determining the fermi level of the sensor in the presence of compounds commonly found in breath that are not indicative of the disease. The results from this study directly apply to the fabrication of a potential pneumonia breath sensor, but are also appropriate for a broad range of applications where volatile organic compound detection is needed.
Thermal Stability Study of Commercial Lithium-Ion Batteries As a Function of Cathode Chemistry and State-of-Charge
Authors: Barkholtz Heather , Preger Yuliya , Langendorf Jill , Lamb Joshua , Chalamala Babu R. , Ferreira Summer , Ivanov Sergei 
Published: February 2020

The safety of lithium-ion batteries is mainly quantified by thermal runaway characteristics such as onset temperature, peak heating rate (HR), and maximum pressure release. This talk evaluates the materials aspects of thermal runaway of commercial lithium-ion batteries by correlating the contributions from individual cell components to thermal runaway trends. An accelerating rate calorimeter was used to define the thermal runaway behavior of three commercial 18650 lithium-ion batteries (LiCoO2, LiFePO4, and LiNixCoyAl1-x-y­O2) at various states of charge (SOC). Cells were also disassembled and the thermal properties of their component materials was evaluated by thermogravimetric analysis, differential scanning calorimetry, and temperature-resolved X-ray diffraction. Broadly, lithium-ion battery thermal runaway process begins with solid-electrolyte interface and negative active material decomposition followed by the positive active material breakdown. The experimental results show that the onset temperature is generally independent of SOC and peak HR increases with SOC as a result of cathode destabilization. Overall, LiNixCoyAl1-x-yO2 decomposes readily, and charged LiCoO2 is also metastable, although it decomposes more gradually than LiNixCoyAl1-x-y. Contrary to the layered transition metal oxides, LiFePO4 is stable to > 500oC, even when charged. The results are aimed at informing future engineering and fire protection of commercial lithium-ion batteries.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2018-3360 A