bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards Functional Advanced Materials Using Ordered Anodic Oxides Supports and Templates
Authors: Macak Jan M. , Kohoutek Tomas , Kolar Jakub , Wagner Tomas
Published: February 2020

Synthesis of highly-ordered nanostructures of valve metal oxides has recently attracted huge scientific and technological interest motivated by their possible use in many applications. The nanoporous Al2O3 – most established member of this group of materials – has been prepared by anodic oxidation of Al under suitable electrochemical conditions nearly two decades ago into perfectly ordered, honeycomb-like porous structures [1]. Owing to the flexibility of the pore diameter/length and the relative ease of the Al2O3 dissolution, its porous membranes have been since than widely used as templating material of the choice for a range of materials [2-4].

It is the TiO2 [5] that has received the highest attention after Al2O3 motivated by its range of applications, including photocatalysis [6], water splitting [7], solar cells [8] and biomedical uses [9]. Very significant research efforts have led to reproducible synthesis of self-organized TiO2 nanotube layers by means of anodic oxidation [10-14], during which the starting Ti substrate is converted into highly-ordered nanotubular layer by anodization in suitable electrolyte.

Although many applications of the nanoporous Al2O3 and nanotube TiO2 nanotube layers have been presented, their potential for the synthesis of advanced functional nanomaterials, in particular when considering all possible shapes and geometries, has not at all been exploited.

In the presentation, we want to focus in detail on various filling routes of anodic templates and supports. We will show examples of various functional devices including some very recent results on chalcogenide-sensitized TiO2 nanotubes [15] and on the new design of resistive switching of memory switching cells using porous AAO templates [16].

References

1) H. Masuda, K. Fukuda, Science, 268 (1995) 1466.

2) H. Masuda, H. Yamada, M. Satoh, H. Asoh, M. Nakao, and T. Tamamura, Appl.
Phys. Lett. 71 (1997) 2770.

3) K. Nielsch, F. Müller, A.-P. Li, U. Gösele, Adv. Mater. 12 (2000) 582

4) H. Asoh et al., J. Electrochem.Soc. 148 (2001) B152.

5) J.M. Macak et al., Curr. Opin. Solid State Mater. Sci. 1-2 (2007) 3.

6) A. L. Linsebigler, G. Lu, J. T. Yates, Chem. Rev., 95 (1995) 735.

7) A. Fujishima and K. Honda, Nature 238 (1972) 37.

8) B.O´Regan and M.Grätzel, Nature 353 (1991) 737.

9) Y.T. Sul et al., Biomaterials, 23 (2002) 491.

10) V. Zwilling, M. Aucouturier and E. Darque-Ceretti, Electrochim. Acta 35, (1999) 921.

11) J. M. Macak, H. Tsuchiya, P. Schmuki, Angew.
Chem. Int. Ed. 44 (2005) 2100.

12) J. M. Macak, et al., Angew.
Chem. Int. Ed., 44, 7463 (2005).

13) S. Albu, A. Ghicov, J M. Macak, P. Schmuki, Phys. Stat. Sol. (RRL), 1 (2007) R65.

14) S.So, K. Lee, P.Schmuki, J.Am.Chem.Soc. 134 (2012) 11316.

15)J.M. Macak, T. Kohoutek, L. Wang, R. Beranek, Nanoscale, 5 (2013), 9541.

16) J. Kolar, J.M. Macak, K. Terabe, T. Wagner, J.Mater. Chem.C, DOI:10.1039/C3TC31969E.
Adsorption Characteristics of Thiophene on Cu and Ni(100): Role of Van Der Waals
Authors: Rojas Tomas , Matos Jeronimo , Kara Abdelkader
Published: February 2020

We apply density functional theory, with and without the inclusion of self-consistent van der Waals (vdWs) interactions (optB86, optB88, optPBE, revPBE, rPW86), to study the adsorption of thiophene (C4H4S) on Cu(100) and Ni(100). Our calculations reveal that the C4H4S molecule adsorbs, on either substrate, with its molecular plane parallel to the surface with the sulfur close to the bridge site.

The inclusion of vdWs interactions results in a significant increase in the binding energy of thiophene on Cu(100) (from 0.12 eV to up to 0.77 eV), while the adsorption height is also modified from 3.2 A down to, at most, 2.38 A, depending on the functional used. The Ni(100) case presents a similar behavior for the binding energy (enhancement from 1.56 eV to up to 2.34 eV), but the adsorption heights increase from 2.12 Å up to 2.32 Å.

In addition to adsorption geometry and energetics, we present the results and analysis of the electronic properties (charge transfer, changes in the d-band of the substrate, and change in the work function) of these two systems to complement our understanding of the molecule-substrate bonding.

Our results suggest that the adsorption characteristics are dependent on the type of functional used; opt-type functionals (optB86, optB88, optPBE) are found to produce stronger bonding as compared to PBE, revPBE and rPW86.

This work is funded by the U.S. Department of Energy Basic Energy Science under Contract No DE-FG02-11ER16243
Study of Hetero-Tunneling Gfet with an Ultra-Shallow Pocket Junction
Authors: Xu Gaobo , Xu Qiuxia , Yin Huaxiang , Wang Guilei , Liu Jinbiao , Xiong Wenjuan , Li Chunlong , Wang Dahai , Li Junfeng , Zhao Chao
Published: February 2020

Because the subthreshold swing (SS) of a MOSFET is larger than 60mV/dec at room temperature, its threshold voltage cannot be very small. This limits the scaling of power supply voltage (VDD) and the reduction of power density. Tunnel field effect transistor (TFET) can overcome this fundamental limitation, which mechanism is based in the band-to-band tunneling (BTBT). However, the drive current in TFETs is significantly lower than in MOSFETs owing to tunneling resistance which arises due to carrier tunneling. Achieving large drive current at low VDDhas been a great challenge. Green transistor (gFET) is a novel structure TFET with a heavily doped pocket in the gate-source overlap region. The pocket junction can provide large and uniform field over a substantial area, which can offer larger drive current and steeper subthreshold swing as compared to conventional tunneling transistors. And, when the pocket junction depth becomes shallower, the drive current will be improved significantly. But study reveal that gFET is only suitable for orepation at 0.5V. To further reduce Vdd, even smaller bandgap material may be employed.

In this study, a hetero-tunneling gFET with an ultra-shallow pocket junction has been developed, as shown in Fig.1. The gFET was fabricated in a 8inch (100) silicon (Si) substrate, as shown in Fig.2. After LOCOS formation, silicon-germanium (Si1-xGex) and Si cap layer were grown on Si substrate using selective epitaxy. After source implantation, an ultra-shallower pocket is formed by using of the Ge preamorphization implantation (PAI), ultra low energy implantation and spike annealing. Si1-xGex and Si have different lattice constant. Biaxially strained will be formed in the Si1-xGex/Si heterostructures. The biaxial strain will shift the conduction and valance band energy levels of semiconductors and obtain ultra low effective tunneling bandgaps, which is helpful to get smaller tunneling length and barrier height. The same current can be obtained at lower gate voltage and drain voltage. The hetero-tunneling gFET integrated with the ultra-shallow pocket junction exhibits good electrical characteristics, such as smaller subthreshold swing, higher Ion/Ioff ratio and so on.
Characterization of Changes in the Surface Properties of Silicon and Porous Silicon after Interaction with Hydroxyl Radicals
Authors: Muñoz Eduardo Carlo , Navarrete Emilio Alonso , Heyser Cristopher Alejandro , Henríquez Rodrigo Gonzalo , Schrebler Ricardo Silvio , Córdova Ricardo Alejandro
Published: February 2020

Free radicals (FR) can be formed inside cells as a result of physiological processes such as food metabolism, respiration or pollutants generated by effects such as snuff radiation, among others. Its accumulation can be harmful to nearby cells or in contact with a tissue or organ [
[i]
]. It is for this reason that various investigations have focused their interest to the detection and quantification of these FR, in order to find materials that enable in-vivo sensing these FR and in particular the hydroxyl radical (OH), because of its high oxidation potential +2.32 V [
[ii]
].

In this study we examined the changes on the surface properties of crystalline silicon (n -Si) and porous silicon (n-PS) as a function of exposition time to hydroxyl radicals generated by Fenton reaction and by means of the reaction between hydrogen peroxide electrochemically generated with iron (II) ions (electrofenton). Morphological, optical and wetting degree characterizations were performed for the evaluation of changes on the surface properties of these substrates. For morphological analysis, Atomic Force Microscope (AFM) was employed, evaluating pore size distribution on n-PS and y¡the influence of the exposition to FR. Changes in optical properties were analyzed by means of photoluminescence (PL) of n-PS exposed at OH radical at different periods and analyzing changes on the intensity of this signal. Finally, the wetting degree was analyzed by contact angles in two stages: (i) sessile drop method (ex- situ); (ii) captive bubble method (in- situ). The results obtained indicate a change in the silicon hydrophobicity/hydrophilicity as a function of exposition time to OH radicals. These changes have been associated with the dynamic surface transformation of silicon surface groups from Si - H (after cleaning treatment ) to Si - OH (after exposure to hydroxyl radical).

[[i]] Robert E. Huie and P. Neta. Chemistry of reactive oxygen species Part I. Kluwer academic publishers, (2002) New York, 33 -63pp.

[[ii]] Fritz Scholz, Gabriela López de Lara González, Leandro Machado de Carvalho, Mauricio Hilgemann, Khenia Z. Brainina, Heike Kahlert, Robert Smail Jack, and Dang Truong Minh. Angewandtechemie international edition.
46, (2007) 8079 –8081.
Electrochemical Study of the Interaction Between Silicon n–type (100) and Hydroxyl Radicals
Authors: Muñoz Eduardo Carlo , Heyser Cristopher Alejandro , Scholz Fritz , Hasse Ulrich
Published: February 2020

Semiconductor materials offer electronic properties that make them promising for being employed in the molecules detection in different environments. The present study proposes the analysis of changes in electrochemical responses of crystalline silicon (n–Si) after the interaction with hydroxyl radicals (•OH) in aqueous media.

In a first stage, the synthesis of hydroxyl radicals was done by means two procedures: (i) Fenton reaction and (ii) H2O2 photochemical decomposition using a UV digester for this purpose. Variables in these processes were time and hydrogen peroxide concentration in order to determine the dependence of these parameters on silicon–hydroxyl radical interaction.

After each immersion in radicals (separately both methods •OH of generation), it was performed a chemical cleaning treatment on silicon, which consisted: i) without further treatment; ii) HCl treatment or iii) HF treatment. This last was done to avoid the presence of silicon oxide (SiO2) on the semiconductor surface. Subsequently, n–Si was placed in a three electrodes cell: silicon as working electrode, Ag / AgCl, KCl (saturated) as a reference electrode (0.197 V vs SHE) and a platinum counter electrode. After were registered the corresponding voltammograms in a potassium chloride (KCl 0.1 M) solution at different pH values. In order to study the pH dependence on the interaction between substrate – reactive species (Si – •OH) were analyzed the current and the peak potential shift for each experimental conditions. Finally, Atomic Force Microscopy (AFM) was done to observe morphological changes in the substrate surface.
Direct in-Situ Nitridation of Nanostructured Metal Oxide Deposited Semiconductor Interfaces, the Formation of Reversibly Interacting Basic Sites
Authors: Laminack William , Baker Caitlin , Gole James L.
Published: February 2020

We study the reversible response matrices formed at room temperature as metal oxide nanostructure decorated interfaces are modified through in-situ nitridation. Nanostructured TiO2, SnOx, NiO, and CuxO (x= 1,2), in order of decreasing Lewis acidity are deposited to an n-type nanopore coated microporous porous silicon (PS) interface to direct a dominant electron transduction process for reversible chemical sensing in the absence of significant chemical bond formation. The metal oxide sensing sites can be modified to decrease their Lewis acidity in a process of amination (triethylamine) which substitutes nitrogen, providing a weak interaction to form sites of the metal oxynitrides. This trend is characterized by XPS measurements of the shift in the binding energy from that of the oxides and by infrared spectroscopy. The in-situ modification of the metal oxides deposited to the interface changes the reversible interaction with the analytes NH3 and NO. Response measurements as a function of NH3 and NO concentration demonstrate the significant effect which the nitridation and apparent oxynitride formation has on the coupling to the decorated semiconductor majority charge carriers. The relative responses of the nitridated interfaces are not simply the result of creating more basic surface sites. As the substitution of nitrogen for oxygen lowers the Lewis acidity of the metal sites the nitridated metal oxides shift on the acidity scale of effectively greater basic character. However, the analyte basicity or acidity does not change. The responses to the analyte change in distinctly different ways which are predictable within the framework of the IHSAB model. Thus, nitridation significantly changes the response matrix for a given gas and, creating a distinct new family of response matrices which are determined by the acidity/basisity of a given analyte relative to the nanostructures which decorate the PS interface. The response matrix for a given analyte due to the metal oxide decorated PS interface is therefore changed in a substantial and predictable way The results of this modification are well explained by the recently developed IHSAB model of reversible electron transduction. This work is now being extended to the study of interaction with the sulfur based analytes of the sulfides (basic) and thiols (acidic)
Quantum Dot Based Sensing Platform for Selective Detection of Volatile Organic Compounds and Biomarkers
Authors: Sarswat Prashant , Free Michael L
Published: February 2020

Diagnosing and monitoring diseases such as lung cancer often involves expensive testing in advanced stages of disease development. If a low cost method to diagnose and monitor diseases such as lung cancer were available, earlier detection and improved prognosis would result. Diseases such as lung cancer and diabetes cause changes in body chemistry that result in the release of volatile organic biomarkers that are often very distinct and different than those of healthy patients. Therefore, appropriate noninvasive and low cost analysis of patients’ breath can lead to early diagnosis and monitoring. The objective of this research is to understand and improve new non-invasive selective sensors to quantify volatile organic biomarkers for improved health monitoring. These specialized sensors consist of quantum dots, dye, and a current collector. The dye becomes colored when exposed to volatile organic biomarkers without a significant difference in color for different biomarkers. However, when the dye is tethered to quantum dots and exposed to light, the color for each biomarker is quantifiably different. The quantum dots are semiconducting and facilitate the charge transfer event, which is directly related to biomarker concentration, that can be collected using nanostructures such as titania nanotubes on titanium metal. Thus, the combination of quantum dots, dye, and a current collector creates a sensitive and selective sensor for volatile organic biomarkers (VOBs), such as those associated with a variety of diseases.
Co-Doped ZnO Nanomaterials As a Novel Platform for Hydrogen Peroxide Biosensing
Authors: Zhang Wen , Chang Yingxing
Published: February 2020

Co-doped ZnO nanomaterials have been synthesized successfully on indium tin oxide glass by direct electrochemical deposition using as a platform to immobilize horseradish peroxidase enzyme and to enhance the response of hydrogen peroxide. The crystal structures and morphology of Co-doped ZnO were characterized by X-ray diffraction and scanning electron microscopy, whereas surface electronic state and the element ratio were revealed by X-ray photoelectron spectroscopy measurements. Cyclic voltammetric and electrochemical impedance spectroscopy were carried out with the electrodes, and it was found that the Co-doped ZnO nanomaterials had good conductivity and fast electron transfer in electrocatalytic reduction. According to the amperometry response, a broad linear response was in the range of 0.05 to 1.15 mM and the detection limit was 13 mM at a signal-to-noise ratio of 3 (S/N=3) within 10 s at an applied working potential of -0.3V. The sensitivity and value for the electrode were 22.7 mA mM-1 and 2.93 mM, respectively. The proposed biosensor was not affected by other pollutants and maintained nearly 90% of its original activity after a monthly storage. These results indicate that proper doping can improve electron transfer abilities of ZnO and enable this traditional semiconductor material to have better performance in sensing applications.
Universal Electrochemical Probe for Genotyping
Authors: Tran Kristen , Borchardt Gesca , Calvo-Marzal Percy , Chumbimuni-Torres Karin Y.
Published: February 2020

DNA analysis is a fundamental topic of research leading to many studies related to the detection of disease-causing microbes, gene variations causing genetic disorders, DNA mapping, and evolutionary links between ancient and modern remains. This study uses stem-loop folded DNA (SLF-DNA) probe immobilized on the surface of an electrode as a part of tri-component sensor for detection of specific DNA. The advantages over traditional methods such as Southern and Northern Blots, or PCR amplification include the possibility to detect low quantities of unlabeled target analyte, high specificity of nucleic acid recognition and possibility to use the same immobilized DNA probe for detection of many different sequences.

In our approach hairpin shaped oligonucleotide (SLF-DNA) is immobilized onto a gold electrode and the signal of specific tag is measured. Importantly, immobilized SLF-DNA does not directly hybridize with the target analyte, but via the two adaptor strands. This design allows application of the same electrode in the same immobilized adaptor strand to be used for the detection of almost any target, relatively inexpensive adaptor should be changes to recognize a new DNA/RNA analyte. These electrochemical biosensors are simple to use, low cost, low power, portable with fast response times, and high specificity and sensitivity.
Some Observations on the Challenges of Chemical Sensor Commercialization
Authors: Wohltjen Hank
Published: February 2020

Chemical sensors continue to offer significant commercialization potential. They are an enabling technology of the ever-expanding digital world that seeks to measure (and control) our environment, our health and our manufacturing processes. The development and commercialization of chemical sensors has always been much more challenging than the development of physical sensors due to the vast number of potential measurands, the complexity of potential interferences and the (comparatively) low production volumes that existing markets will support.

This talk is aimed at aspiring entrepreneurs and will use the development of some Surface Acoustic Wave (SAW) chemical sensor products as a case history. Particular attention will be given to detailing the chronology and issues encountered in the following steps:

• initial invention and establishing the limits of the technology

• identifying suitable niche applications

• product development & system engineering

• validation and agency approvals

• production

• marketing, sales and servicing

Commercially successful products can result when the initial customer needs are deeply understood, the sensor performance exceeds market expectations, the time-to-market (and associated capital requirement) is correctly predicted and the market-acceptable selling price of the sensor is high enough to support the cost of production.
Opportunities and Challenges in Sensor Design for the Drinking and Wastewater Markets
Authors: Kroll Dan , Salzer Corey
Published: February 2020

The water and wastewater industries face many challenges in providing safe drinking water, sanitary services and environmental protection to the public. The dynamic nature of our water systems along with new regulations, emerging contaminants and increasing environmental concerns combined with the constant pressure to reduce operating costs and conserve energy make the development of sensors for the water industry a field ripe with opportunity. As with all areas of opportunity, to be successful in developing sensors for the water industry there are hurdles to overcome and pitfalls to be avoided.

Harsh environmental conditions in wastewater sensor deployment scenarios are a given, but, the severe conditions commonly encountered in drinking water applications are often not addressed with the diligence that they merit. Factors such as debris in the pipes, turbidity, fluctuating pH, various types and levels of disinfectants and other water treatment chemicals; fluctuating redox conditions and variable conductivity are just a few of the complicating elements that can hamper sensor development. Once a sensor has been developed the last hurdle has been by no means cleared.

The water industry is a notoriously reactionary group. The barriers to change are extremely large and adoption curves for new technologies tend to be extremely slow. One of the chief factors in these slow adoption rates is the glacial pace of regulatory acceptance of new methods. Even for measurements not taken for reporting purposes, the industry tends to favor methods that have EPA or other regulatory body approval. Unfortunately, this approval process can take several years (2 to 3 years for drinking water and up to 7 years for wastewater applications). There are several industry initiatives sponsored by groups, such as the Water Environment Federation, that are attempting to speed up the innovation curve in the water industry but these groups are just beginning to act and it is unknown if they will meet with success.

In this presentation, the above constraints will be discussed, as well as others, which are commonly encountered in the research and development cycle for sensors tailored to the water industry. Examples of obstacles encountered in a recent development project initiated for the use of nano-fibers in sensors for the water industry will be utilized to illustrate various points. A thorough knowledge of the technological pitfalls to be avoided as well as an understanding of the market and regulatory forces that can come into play in this market arena will lead to the development of robust sensors that serve the industry and help to ensure developers of a reasonable return on investment.
Evaluating the Corrosion Behaviour of PVD Al-Based Coatings By Characterising the Relaxation Time of the Open Circuit Potential in AC-DC-AC cyclic tests
Authors: Indeir Fahima , Leyland Adrian , Matthews Allan
Published: February 2020

A recently developed AC-DC-AC cyclic test method is used for the first time to evaluate the corrosion behaviour of PVD Al-based coatings. The technique can induce relatively rapid coating degradation as the cathodic reactions at the coating/metal interface produce OH- ions and H2 gas. The AC-DC-AC cyclic test steps involve characterising the coating properties using electrochemical impedance spectroscopy (EIS), a DC cathodic potential step (this is applied for given period of time to induce the electrochemical reactions that cause coating damage) and a potential relaxation stage (when the open circuit potential (Eoc) is monitored over a given time for the coating to reach a stable Eoc condition). This relaxation time defines when cathodic reactions stop and the processes such as electrolyte/ion travel from the coating, pore formation, corrosion reactions and double layer stabilisation that were accelerated (by DC polarisation) reach the steady state. The analysis of Eoc during AC-DC-AC cyclic test involves the regression of an expression describing the potential relaxation which includes two summed terms attributed to i) the end of cathodic reaction and ii) to expulsion of electrolyte ions from the coating. The new AC-DC-AC test technique provides a rapid evaluation of corrosion degradation behaviour of PVD AlCr(Ti) coatings in a shorter time (≤ 24hrs) than traditional EIS and SST tests (days or weeks). The influence of applied DC was determined by subjecting constant voltages of -2V -4V, and -8V to the PVD Al-based coating relative to the stable Eoc value.
Corrosion Protection Studies of Crude Glycerol-Based Waterborne Polyurethane Coatings on Steel Substrates. (oral)
Authors: Lee Yueh-Lien , Luo Xiaolan , Hu Shengjun , Li Yebo , Buchheit R.
Published: February 2020

Crude glycerol (CG), a low-value byproduct from the biodiesel industry, has a significantly different composition compared to pure glycerol. Generally, crude glycerol contains various impurities, such as methanol, water, soap, free fatty acids (FFAs), fatty acid methyl esters (FAMEs), and glycerides. In this study, the performance of crude glycerol-based waterborne polyurethane (PU) coatings synthesized using crude glycerol as a sole feedstock via a thermochemical conversion process was studied. The corrosion properties of coatings were characterized by electrochemical impedance spectroscopy (EIS), polarization measurement and salt spray test. The experimental results show that crude glycerol-based PU coatings have a considerably enhanced corrosion resistant performance of metallic substrate (phosphated steel).
Diffuse Interface Modeling and Multi-Scale Relay Simulation of Thermal Oxidation of Metals
Authors: Cheng Tianle , Wen Youhai , Hawk Jeffrey A.
Published: February 2020

The oxidation kinetics of metals/alloys at elevated temperature is essential to the corrosion-life prediction of the structural materials in advanced energy systems. The oxide film growth on metal surface typically involves coupling of chemical reaction, ion diffusion and electrostatic interaction. A diffuse interface oxidation model plus a multi-scale-relay algorithm are developed to address the essential processes and their interplay over a wide range of length/time scale during metal oxidation. As a result, the transition of growth law of oxide films across orders of magnitude in length/time is computationally captured without a priori assumptions. The results are compared to the oxidation models developed by Wagner, Kröger, Deal and Grove, and Fromhold et al. The common assumptions used in the literature such as steady state, local equilibrium and local charge neutrality and their validity are investigated.
Surface Treatment of Plastics with Ionic Liquids for Decorative Metal Deposition
Authors: Kirste Axel , Lutter Simone , Son Sunghee , Urban Tobias , Nicolini Fabio , Fischer Andreas
Published: February 2020

Surface treatment of plastics for decorative metal plating has been developed for more than 20 years and is widespread applied in automotive, electronics and faucets industries. Main advantages in contrast to the use of bulk metals are savings of weight and costs, facilitating complex geometries and superior aesthetic appearance. Most applied plastics represent acrylonitrile butadiene styrene polymers (ABS), ABS polycarbonate blends and polyamide. Etching of the plastic surface is required to enable the electroless plating of metals like nickel or copper. State of the Art for surface activation is etching with hexavalent chromic sulfuric acid. It is cost efficient, robust and reliable.[1] Generally known, hexavalent chromium causes high environmental, health and safety impact. Moreover, the scope of application to different plastics is quite limited. Therefore, a sustainable and environmental-benign replacement of this substance of very high concern is demanded in the near future. Some concepts for the replacement of chromic acid are currently under investigation. The most public approaches are the use of potassium permanganate[2] or ozone[3]. Disadvantageously, these concepts improve health, safety and environmental impact only marginally. Moreover, complex waste handling and process equipment limit the potential as suitable substitute.

We report a potential and metal-free replacement approach based on surface treatment with ionic liquids. Employed ionic liquids and additives bear substantial environmental, safety and health advantages. Beyond, they show high potential for broadening the scope of applied plastics.[4]

References:

[1] H. Midecke, J. McCaskie, N. H. Joshi, DE 19510855 A1, 1995.

[2] A. J. Königshofen, US 2003/0039754 A1, 2003.

[3] T. Bessho, K. Isami, K. Kumagai et al, US 2011/064889 A1, 2011.

[4] I. M. Malkowsky, A. Alemany, PCT Int. Appl. WO 2010/142567 A1, 2010.
Synthesis of Co-Deposited Electroless Pd-Cu Catalyst for Nitrate Reduction
Authors: Anderson Shannon , Onyeozili Edith N , Kalu Egwu Eric
Published: February 2020

Electrochemical and thermodynamic data obtained from the determination of the corrosion (or open circuit potential or oxidation/reduction) potentials of Cu and Pd in various reducing agents (formaldehyde, hypophosphite and ammonia borane) and their mixtures was used to formulate a stable electroless bath for co-deposition of Cu and Pd on Al2O3 substrate. The electrolessly deposited Pd-Cu catalyst was characterized using SEM, EDAX and BET measurements. The Pd-Cu catalyst on alumina was found to be active for nitrate reduction in aqueous solution. The activity and composition of the catalyst increased with electroless plating time up to 30 minutes whereupon the variation of metal composition was minimal. The BET measurement showed that the electroless plating decreases the BET surface area of the catalyst thereby suggesting a macroporous mechanism for nitrate reduction on electroless Pd-Cu catalyst. A comparison of the performance of supported electroless Pd-Cu catalyst versus unsupported, precipitated Pd-Cu-containing particles showed that the unsupported Pd-Cu particles reduced nitrate at a faster rate than the Al2O3 supported electroless Pd-Cu catalyst but produced more ammonia. The supported electroless Pd-Cu catalyst converted most of the nitrate in solution into preferred nitrogen gas product rather than ammonia.
Contact Resistance Measurement of Electrode on Silicon Prepared By Autocatalytic Electroless Metallization Using Metal Nanoparticles
Authors: Orita Yukiko , Yae Shinji , Atsushiba Hiroyuki , Enomoto Masato , Kimura Toshihiko , Fukumuro Naoki , Takagami Hidenori , Matsuda Hitoshi , Kato Kazuhiko , Sakamoto Susumu , Hirata Masaharu
Published: February 2020

We reported the adhesive metal-film formation by autocatalytic electroless metallization on silicon (Si) by using gold (Au) nanoparticles1). Autocatalytic electroless deposition, which is a conventional method to metalize nonmetallic substrates, has several advantages including simplicity of process, uniformity of films, and the covering of complicated structures. So, the process is expected to replace sputtering of back metal of power devices and screen-printing of thick film electrodes of solar cells. In this study, we determined contact resistance (Rc) between electrolessly deposited metal electrode and Si semiconductor by using TLM (transfer length model) method shown in Fig.1.

Figure 2 shows photo and dimension of test sample, and Fig.3 shows schematic process flow of preparing two test samples; 1. Photoresist pattern formation: 2. Au nanoparticles formation by displacement reaction using a mixture solution of HAuCl4 and HF: 3. Autocatalytic electroless deposition of nickel-phosphorus alloy (Ni-P) film for sample (A), and: 4. Electron-beam silver (Ag) deposition on electrolessly deposited Ni-P film for sample (B). The thickness of Ni-P films was 0.25 mm and Ag thickness on Ni-P film was 1.15 mm.

We measured Rt of samples and determined ρc. Rt and ρc are given by

Rt = 2Rm + 2Rc+ Rs

ρc = Rm + Rc.

Figure 4 shows TLM result of samples (A) and (B). The values of ρc were 140 mΩ cm2 in (A) and 13 mΩ cm2 in (B). These results indicate that the ρc is mainly determined by resistance of bulk metal (Rm) and the contact resistance (Rc) of these samples is lower than 13 mΩ cm2. The Rc of screen-printed-and-fired Ag electrodes of crystalline Si solar cells was reported as 2~3 mΩ cm2 lower than ρc of sample (B)2). Contact resistance (Rc) is important for devices rather than ρc
3). The Rc of electrode prepared by the autocatalytic electroless metallization using Au nanoparticles is approaching the value of conventional electrodes without any heat treatment. We also review interface structure and contacting mechanism between Au nanoparticles and Si semiconductor4).

ACKNOWLEDGEMENTS

The present work was partly supported by JSPS KAKENHI (23560875) and A-STEP from JST.

REFERENCE

1) S.Yae, et al., ECS Trans., 53(6), 99 (2013).

2) Yi Yang, et al., Energy Proc., 8, 607 (2011).

3) P.L.Hower, et al., Semicon. Semimet., 7A, 147 (1971).

4) H. Atsushiba, et al., Abst. 225th ECS meeting (D2), (2014).
Electroless Cu-Ni-Mo Catalyst for the Low Pressure Hydrogenolysis of Glycerol to Propan-1,2-Diol
Authors: Elendu Oyidia , Yeboah Yaw D. , Kalu Egwu Eric
Published: February 2020

A low pressure technique for the hydrogenolysis of glycerol to propan-1, 2-diol is being investigated in stages. The first step involves the development of a Cu-Ni-Mo/Al2O3 prepared by electroless deposition method. The technique of making Al2O3 support active for electroless deposition of copper and is reported (copper and nickel show good hydrogenolytic activity towards this reaction). Work done includes the determination of optimal metal loading, pH and temperature ranges for the supported metal catalysts and the characterization of active catalyst using XRD, TEM SEM and EDAX. Detailed microstructural and texture characterization of the Cu-Ni-Mo/Al2O3 catalysts, and their correlation with glycerol hydrogenolytic activity will be presented.
Electrochemical Characterization of Glassy Carbon/CNT/Chit Scaffold-Attached Bioﬁlms Under Linear Flow Conditions
Authors: Galicia Monica , Castaneda Homero
Published: February 2020

Improvements on carbon-base anode modified with carbon nanotubes (CNT’s) and chitosan polymer (Chit) have been accomplished for the bacteria attachment and better electron transfer in microbial fuel cells by coupling Chit to CNT’s. Arrangements of this nature can be structured into 3D macroporous scaffolds possessing large pore sizes that support bacterial colonization. This work describes the electrochemical and high surface resolution characterization of the growth of thin (<20 µm) bioﬁlms on glassy carbon electrodes modified with Chit dispersed into multiwalled carbon nanotubes (MWCNT). Cyclic Voltamperometry (CV) and Electrochemical Impedance Spectroscopy (EIS) are applied to characterize and assess the interfacial response in anaerobic conditions under laminar flow conditions. In vivo analysis of electron transfer between bacterial cells and electrodes provides insight into the main redox-active species participating in electron transfer to electrodes. CV and EIS also reveal features that are consistent with detections of multiple redox-active species appearing at the outer surfaces of this biofilm with electron transfers. The results are fitted to equivalent analogs. These techniques illustrates specifics quantiﬁable parameters and deﬁned electron transfer processes as a function of potential, electrode material, growth phase, and culture conditions.
In Situ X-Ray Absorption Spectroscopy of Lithium-Sulfur Battery Discharge/Charge Reaction Mechanisms
Authors: Wujcik Kevin , Pascal Tod , Prendergast David , Balsara Nitash P.
Published: February 2020

A necessity to the development of more efficient lithium-sulfur batteries is an understanding of the redox pathways through which soluble Li2Sx reaction intermediates are formed. Spectroelectrochemical studies of the charge/discharge reaction pathways have been complicated by difficulties faced in the assignment of Li2Sx reaction intermediates to spectral peaks. The development of spectroscopic techniques that can clearly differentiate Li2Sxmolecules and be used to perform in-situ studies of Li-S cell chemistry has become an important focus of Li-S battery research.

It has recently been shown that X-ray absorption spectroscopy (XAS) at the sulfur K-edge may be used to speciate Li2Sx molecules of different ‘x’ values.1-4 In this work, in situ XAS of Li-S cell cathodes will be used to probe cell cathodes during charge/discharge. Collected spectra provide full speciation of sulfur throughout charge/discharge processes and reveal the pathway through which polysulfide species are formed. Li-S cells consist of a PEO-based polymer electrolyte and thin film cathodes, employed to mitigate effects of X-ray overabsorption. Interpretation of collected spectra is achieved using a principal component analysis. Theoretical X-ray spectra obtained using first-principles molecular dynamics and spectral simulations of lithium polysulfides dissolved in tetraethylene glycol dimethyl ether (TEGDME) provide further support for spectral interpretation. The molecular origins of observed spectral features are elucidated.

References

(1) Wujcik, K. V., J.; Wu, C.; Pascal, T.; Marcus, M.; Cabana, J.; Prendergast, D.; Guo, J.; Salmeron, M.; Balsara, N.P. Manuscript in Preparation
2014.

(2) Pascal, T. W., K.; Velasco-Velez, J.; Wu, C. H.; Teran, A.; Kapilashrami, M.; Cabana, J.; Guo, J.; Salmeron, M.; Balsara, N. P.; Prendergast, D. Manuscript in Preparation
2014.

(3) Cuisinier, M.; Cabelguen, P.-E.; Evers, S.; He, G.; Kolbeck, M.; Garsuch, A.; Bolin, T.; Balasubramanian, M.; Nazar, L. F. The Journal of Physical Chemistry Letters
2013, 4, 3227.

(4) Patel, M. U. M.; Arčon, I.; Aquilanti, G.; Stievano, L.; Mali, G.; Dominko, R. ChemPhysChem
2014, n/a.
Local Cell Reaction Study for Lead Acid Battery
Authors: Iwai Taichi , Kitajima Daishi , Takai Shigeomi , Yao Takeshi
Published: February 2020

Introduction

Lead acid battery has been widely used for more than 100 years and still now, it is very important for vehicles. Recently, lead acid battery has been intensively studied for the energy storage because of its low cost and high power. However, despite of its long history of study, some chemical reactions in a cell has not been clarified yet. The cathode material is PbO2 which has two types of crystal structures, α- PbO2 and β- PbO2. It is reported that PbO2 exists as β- PbO2 in an acidic region and as α- PbO2 in an alkaline region[1]. However, α- PbO2 also coexists with β- PbO2 in the cathode of lead acid battery and this reason is not revealed well till now. α- PbO2 shows the better cycle performance than β- PbO2 and β- PbO2 shows the larger discharge capacity than α- PbO2
[2]. Therefore, it is important to control the ratio of these two phases for the practical use of lead acid battery.

In the open circuit, local cell reaction between electrode material and current collector (CC) will occur[3]. Till now, the effect of local cell reaction has not been studied enough. In this study, we focused on the local cell reaction between the cathode material (PbO2) and various CCs for lead acid battery. The effect on the formation of α- PbO2 was investigated.

Experiment

β- PbO2 (A Johnson Matthey Company) was mechanically crushed in the mortar for 1d. The cathode was fabricated by mixing powder of the crushed PbO2 as the active material, acetylene black as a conducting additive and PTFE as a binder at the ratio of 80:15:5 by weight. Lead plate was used as counter electrode. The electrolyte was a 30wt% sulfuric acid. Two kinds of CC, platinum mesh and lead plate were used for the cathode to compare the local cell reaction between cathode material and CC. At first, we discharged for 30min at 9mA/g and charged for 20 min at 180mA/g for 20 cycles to make the cell reaction stable. Then, we discharged the cell deeply to the cutoff voltage of 0V at 9mA/g and opened the circuit. After the rest for 1d, X-ray diffraction of the surface of cathode was measured using RINT-TTR (Rigaku co., CuKα, 200mA, 30kV) for each CC.

Results and Discussion

Fig.1 shows XRD patterns after the rest time. Upper pattern (a) shows the result when using lead plate as CC, and lower pattern (b) shows the result when using platinum mesh as CC. The peak of α- PbO2 was observed for pattern (a). However, the peak of α- PbO2 was not observed for pattern (b). In the open circuit, local cell will be formed between electrode material and CC. When using platinum mesh as CC, PbO2 works as an anode and CC works as a cathode. On the contrary, when using lead plate as CC, PbO2 works as a cathode and CC works as an anode. It is suggested that this local cell reaction will affect on the formation of α- PbO2.

References

[1] Battery Handbook, third edition, (2001) 170

[2] E. Kadlecova et al. , PIERS ONLINE, VOL.2, No.6, (2006) 648-652

[3] T. Yao, T. Iwai and H. Tagashira, PCT/JP2013/ 74165 (2013)
Optimal Charging Profile for Lithium-Ion Batteries at Subzero Temperatures
Authors: Suthar Bharatkumar , Northrop Paul W. C. , Braatz Richard D. , Subramanian Venkat R.
Published: February 2020

This presentation considers the problem of obtaining the optimal charging profile of a lithium-ion battery using physics-based thermal-electrochemical coupled models at subzero temperatures. The battery performance is usually very sensitive to temperatures at subzero environment and cannot deliver high rates of current (1). The temperature changes which arise during charging/discharging from subzero temperatures lead to significant changes in the battery dynamics throughout charging. Such major changes lead to charge/discharge behaviors that are not monotonic in voltage (2). This behavior necessitates the use of model based optimization techniques to derive optimal charging profiles which account for the changing temperatures within the cell.

This presentation will discuss optimal charging profiles derived using the thermal single particle model (3) and the reformulated thermal pseudo two dimensional model (4) at subzero temperatures. Special focus will be given to the effect of the surrounding temperature and heat transfer coefficient on performance and the calculated optimal profiles.

Acknowledgements

The work presented herein was funded in part by the Advanced Research Projects Agency – Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000275 and McDonnell International Scholar Academy at Washington University in St. Louis.

References

1. Y. Ji, Y. Zhang and C.-Y. Wang, J. Electrochem. Soc., 160, A636 (2013).

2. Y. Ji and C. Y. Wang, Electrochimica Acta, 107, 664 (2013).

3. M. Guo, G. Sikha and R. E. White, J. Electrochem. Soc., 158, A122 (2011).

4. P. W. C. Northrop, V. Ramadesigan, S. De and V. R. Subramanian, J. Electrochem. Soc., 158, A1461 (2011).

** Electrochemical Society Active Member

z vsubramanian@seas.wustl.edu
Moving Battery Models to Low-Cost Microcontrollers for Enabling Electric Transportation
Authors: Pathak Manan , Sonawane Dayaram , Suthar Bharatkumar , Rife Derek , Subramanian Venkat R.
Published: February 2020

Optimal performance of a proactive Battery Management System (BMS) needs real time knowledge of internal states of the battery such as Sate-of-Charge (SOC), State-of-Health (SOH) and battery power [1]. The effect of inaccurate state estimations may cause severe damage to the battery. The physics based battery models that could predict the internal states are inherently computationally challenging. This is difficult for implementation in dedicated microprocessors or microcontrollers with limited on-chip memory and low CPU clock. Efforts have been made in the past to come up with different low complexity and reformulated models which are capable of being implemented in microcontrollers for BMS operation [2-4].

In this work, we propose reformulated physics-based electrochemical models which are highly computationally efficient to deploy in low cost microcontrollers (like 32-bit AVR or Beagle Bone) for accurate state estimation of batteries. This talk will particularly focus on numerical simulation techniques that enable real-time simulation and optimization in microcontroller environment.

Acknowledgements

The authors acknowledge financial support provided by the US Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E), under award number DE-AR0000275.

References

[1] V. Pop, Battery Management Systems: Accurate State-of-Charge Indication for Battery Powered Applications, Dordrecht, Springer (2008).

[2] M. Farkhondeh, and C. Delacourt, Mathematical Modeling of Commercial LiFePO4 Electrodes Based on Variable Solid-State Diffusivity, J. Electrochem Soc. 159, A177 (2012).

[3] R. Klein, N. A. Chaturvedi, J. Christensen, J. Ahmed, R. Findeisen and A. Kojic, in Proceedings of the American Control Conference, p. 6618 (2010).

[4] P. W. C. Northrop, V. Ramadesigan, S. De, and V. R. Subramanian, “Coordinate Transformation, Orthogonal Collocation and Model Reformulation for Simulating Electrochemical-Thermal Behavior of Lithium-ion Battery Stacks,” J. Electrochem. Soc. 158(12), A1461-A1477 (2011).
Material and Energy Balance of Methanol Feed 1 kW SOFC Power System
Authors: Hsueh Kan-Lin , Ting Fu-Pin , Chang Yu-Ching , Huang Jar-Lu , Cheng Ya-Tang , Chang Wen-Sheng
Published: February 2020

High chemical to electric energy conversion efficiency and ease capture of carbon dioxide makes solid oxide fuel cell (SOFC) very attractive for distributed power generation using natural gas, syngas, biofuel, and methanol as the fuel. A 1 kW prototype power unit was built by ITRI/Hephase using methanol as the fuel. Fig.1 is the flow chart of 1 kW SOFC power unit. The methanol is converted into hydrogen by a reformer. Electric pre-heater is used to maintain the fuel stream temperature for reformer inlet and for SOFC anode inlet. Residue hydrogen in fuel cell exhaust is combusted in an afterburner. Heat produced from the afterburner is used to heat up the inlet air stream of SOFC. Photo of this unit is depicted on Fig. 2. “HotBox” is located at up-left portion. This unit contains afterburner, electric heater, and heat exchanger. Up-right portion is the SOFC stack. Bottom portion is the electric controller/monitor. This power unit was transferred to Taiwan Power company for long-term operation and testing.

A steady state material and energy balance was carried out throughout the entire SOFC system. The polarization curve and operating point used in the model calculation is depicted on Fig. 3. This curve was calculated from equation (1). The Vr, DVact, DVohm, DVconcare equilibrium cell voltage, voltage loss due to electrochemical reaction, voltage loss due to internal resistance, voltage loss due to concentration polarization.

Major heat fluxes among each components and temperature of each streams were calculated. Major efficiency losses were also identified. Typical result is given on Fig. 4. Experimental data were collected. This model and parameters used in the calculation will be adjusted to fit the measured result.

Authors wish to thank the financial support from BOE/MOEA (Bureau of Energy, Ministry of Economic Affairs) and NSC (National Science Council). This work was carried out by researchers under the collaboration among Hephas Energy, Industrial Technology Research Institute/Green Energy and Environment Research Laboratory, National United University, Dept. Energy Engineering, and Taiwan Power Company.