bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrically-Conductive Polymer Composites for Injection-Molded Bipolar Plates
Authors: Chiappazzi Nicholas A , Kypta Chadwick J , Schriner Gregory R , Young Brian A , Santamaria Anthony D. , Hollinger Adam S
Published: December 2020

Bipolar plates are one of the primary components of polymer electrolyte membrane fuel cells. These plates deliver reactants to electrodes, remove reaction byproducts, transfer heat, provide mechanical stability, and conduct electrical current. While graphite is the most commonly used material for fabrication of bipolar plates, the machining costs associated with graphite are a major drawback to mass production. In addition, graphite-based plates make the greatest contribution to the weight of the fuel cell stack. For this reason, we are exploring electrically-conductive polymer composites as an alternative to the traditional metal alloys commonly used for fuel cell bipolar plates. Polymer composites can reduce both the weight and cost of the bipolar plate, while still providing sufficient electrical properties. The main objective of this research is to injection mold polymer composites that will meet United States Department of Energy technical targets for bipolar plate electrical conductivity (> 100 S/cm). In this study, conductive fillers (carbon fiber and carbon nanotubes) were added to nylon at various weight percentages, ranging from 0 to 50%, in order to determine the optimal filler-to-polymer ratio. Sample compositions were then compared by measuring electrical conductivity using a four-point probe method. Conductivities greater than 150 S/cm were achieved, exceeding the US DOE technical target.
Enhanced Photocatalytic Activity from Tungsten and Fluoride Dual Modified Titanium Dioxide
Authors: Zhang Xiao LI , Liu Zhongyuan
Published: December 2020

Possessing promoted chemical reactions under ultraviolet or visible light, photocatalysis is one of the most promising and feasible technologies in advanced oxidation processes. Due to the advantages of low cost, earth-abundance, non-toxicity and high resistance to corrosion/photocorrosion, titanium dioxide has become an excellent candidate for environmental and sustainable applications in our daily life and industrial sectors. TiO2 nanoparticles with large specific surface area offer abundant active sites and suitable band edge position, which makes them one of the most desired materials for photocatalytic applications. In the current work, a dual functional one-pot synthesis strategy involving tungsten doping and trace-level fluorination has been developed. Combined characteristic analyses and density functional calculation (DFT) suggest that the noteworthily improved photocatalysis under both ultraviolet and visible lights can be attributed to rapid charge separation and transfer due to the successfully narrowed bandgap from tungsten doping and a localized spatial charge separation by surface F-adsorption.
Structure-Controlled Perovskite Thin Layer Formation on Au Single-Crystal Substrate via Self-Assembled Monolayer of 4-Aminothiophenol
Authors: Takahari Mami , Kondo Toshihiro
Published: December 2020

1. Introduction

In order to solve recent energy and environmental problems, construction of a photoelectric conversion device using a perovskite structure has recently attracted much attention because perovskite structure absorbs visible light very much [1]. In this type of photoelectric conversion device, it is necessary to construct on a solid substrate while maintaining the perovskite structure. In order to improve efficiency, moreover, it is important to control the interfacial structure between the solid substrate and the perovskite film by an atomic dimension. In the present study, we tried to construct a perovskite layer on a Au(100) single-crystal substrate while maintaining the perovskite structure completely and control the interfacial structure between the substrate and the perovskite layer by using a self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) by an atomic level.

2. Experimental

Au(100) single-crystal as a substrate and 4-ATP having an amino terminal group as a SAM molecule were chosen. After annealed and quenched the Au(100) substrate, it was immersed in the hexane solution containing 1 mM 4-ATP for 3 hours at room temperature (RT). Then, the 4-ATP SAM modified Au(100) substrate was sequentially immersed in each DMF solution containing 1 mM PbBr2 and 1 mM MABr for 24 hours for 3 cycles, followed by heating at 135 °C, and then MAPbBr3 perovskite thin films were constructed on 4-ATP SAM modified Au(100) surface [2]. The structure and composition of 4-ATP SAM modified Au(100) substrate after immersion in each solution were evaluated by X-ray photoelectron spectroscopy (XPS) and the crystal structure of the constructed perovskite thin film was evaluated by surface x-ray diffraction (SXRD) as compared with XRD of the corresponding perovskite crystal.

3. Results & Discussion

Figure 1 shows the SXRD profile of the perovskite thin film and the XRD profile of the perovskite crystal. In the SXRD profile, only the (0kl) reflections such as (002) and (012) of the perovskite crystal, which was indicated by triangles in Fig. 1(a), and no diffraction peaks of the (hkl) (h is not zero) reflections such as (112) and (122), which was indicated by stars in Fig. 1(b), were observed. Based on these results, it is indicated that the constructed perovskite thin film was grown along the [100] direction, and we can conclude that it is succeeded to construct the structure-controlled perovskite thin film on the Au(100) surface.

References

[1]A. K. Jena, A. Kulkarni, and T. Miyasaka, Che
m. Rev. 119 (2019) 3036.

[2]L. Zuo, Q. Chen, N. D. Marco, Y. T. Hsieh, H. Chen, P. Sun, S. Y. Chang, H. Zhao, S. Dong, and Y. Yang, Nano Lett.17 (2017) 269.

Figure Captions

Fig. 1 (a) SXRD profile of the perovskite thin film constructed on Au(100) in the present study. (b) Powder XRD profile of the synthesized perovskite powder.

Figure 1
Mechanism of Potential Oscillation (Named Oscillation K) Induced By pH Increase at Electrode Surface in “H2O2-H2so4-Pt Electrode” System
Authors: Okada Haruki , Mukouyama Yoshiharu
Published: December 2020

Electrochemical oscillations are attractive phenomena from the viewpoint of dynamic self-organization of molecular systems. In general, an N-shaped negative differential resistance (N-NDR) plays a crucial role for the appearance of oscillations because it gives rise to an oscillatory instability. Most of the oscillations can be classified into an N-NDR type or “hidden” N-NDR (HN-NDR) type oscillator. The former shows current oscillations under potential controlled conditions and hysteresis loops under current controlled conditions, whereas the latter shows not only current oscillations but also potential oscillations. Thus, an electrochemical system that shows potential oscillations mostly falls into an HN-NDR type oscillator.

Interestingly, the reduction of H2O2 at Pt electrodes in H2SO4 solution shows eleven types of electrochemical oscillations, named sequentially from A to K [1-3]. Oscillations H, I, J, and K appear when a salt such as Na2SO4 and K2SO4 is added to the solution. In the presence of the alkali metal ions originated from the salt, the transport rate of H+ to the electrode surface decreases because the electromigration of H+ is inhibited by the metal ions. Thus, the local pH at the electrode surface becomes strongly basic during the H2O2 reduction even though the electrolyte solution is strongly acidic (e.g., 0.1 M H2SO4). In the vicinity of the electrode surface, H2O2, which is a weak acid with a pK
a of 11.7, dissociates to form HO2
- ion. The ion is electrochemically reduced to OH- or oxidized to O2, leading to the appearance of the oscillations.

In this work, the extent of the local pH increase is estimated by using a numerical simulation and the mechanisms of oscillation K is studied based on the simulation.

REFERENCES

[1] Y. Mukouyama, H. Kawasaki, D. Hara, Y. Yamada, S. Nakanishi, J. Electrochem. Soc.,
164 (2017) H1.

[2] Y. Mukouyama, H. Kawasaki, D. Hara, Y. Yamada, S. Nakanishi, J. Electrochem. Soc.,
164 (2017) H675.

[3] R. Mizuochi, M. Kikuchi, Y. Yamada, Y. Mukouyama, S. Nakanishi, ECS Meeting Abstracts, MA2018-02, 2122 (2018).

FIGURE CAPTION

Figure 1 Current (j) - potential (U) curves for 0.1 M H2SO4 + 0.3 M H2O2 + x M Na2SO4 where x = (top) 0 and (bottom) 0.1, measured (left) under potential controlled conditions and (right) under current controlled ones.

Figure 1
Comparative Oscillatory Electro-Oxidation of Formic Acid on Palladium and on Platinum
Authors: Melle Baptista Gabriel , Romano Rafael , Altair Thiago , Varela Hamilton
Published: December 2020

The electro-oxidation of formic acid has been extensively studied, mainly because of two reasons. From the applied perspective, formic acid has been pointed out as one of the most promising molecules to be used in fuel cells. On the other hand, from the fundamental perspective, it has been used as a model system to study the electro-oxidation of other small organic molecules [1,2]. Despite the large amount of studies concerning the electro-oxidation of formic acid, some mechanistic issues remain to be well understood. In this work, we report a comparative study of the electro-oxidation of formic acid on polycrystalline platinum and palladium electrodes under oscillatory regime. The experiments were performed under potential control mode, with an external resistance coupled between the working electrode and the potentiostat. All results are shown in terms of Phi potential, that is, the electrode potential compensated by the external resistance. On platinum, the oscillations develop between ~0.58 and ~0.80 V, with an oscillatory frequency in the range of 0.78 – 1.49 Hz. As a general trend, the potential slowly increases from ~0.58 to ~0.62 V, followed by a sudden increase to ~0.80 V. On palladium, a very different behavior was observed in oscillation’s waveforms and frequencies. The oscillations develop between ~0.25 and ~0.55 V, with an oscillatory frequency in the range of 0.17 – 0.20 Hz. At the beginning, there is an abrupt increase in the electrode potential from ~0.25 to ~0.38 V. After that, the potential slowly increases until ~0.55 V, when it falls abruptly to ~0.25 V, and the process restart. Overall, the results suggest that the surface chemistry underlying the dynamics of formic acid electro-oxidation on palladium and on platinum is considerably different, particularly under oscillatory regime. Results suggest that the surface poisoning due carbon monoxide adsorption on palladium system is different when compared to platinum, even though the reaction steps for oxidation is similar in both systems. The low frequency oscillations observed on palladium indicates a slower poisoning process on its surface. Consequently, provide us perspectives on mechanistic aspect of this system, not yet treated in much detail. Thus, a broad discussion about the mechanistic issues of those systems will be presented.

References

[1] X. Yu, P.G. Pickup, Recent advances in direct formic acid fuel cells (DFAFC), J. Power Sources. 182 (2008) 124–132. doi:10.1016/j.jpowsour.2008.03.075.

[2] A. Calderón-Cárdenas, F.W. Hartl, J.A.C. Gallas, H. Varela, Modeling the triple-path electro-oxidation of formic acid on platinum: Cyclic voltammetry and oscillations, Catal. Today. (2019). doi:10.1016/j.cattod.2019.04.054.
(Invited) Low-cost 3D Gel Printer as Soft and Wet Industrial Materials Easy Realizer Developed by Virtue of RepRap Open Source Project
Authors: Saito Azusa , Yamazaki Yuta , Watanabe Yosuke , Shiblee MD Nahin Islam , Khosla Ajit , Ogawa Jun , Kawakami Masaru , Furukawa Hidemitsu
Published: December 2020

Soft hydrogel, which contains a amount of water and also has a unique touch feeling, will be required for practical applications around soft-matter robotics including the medical field because it has an unique softness that is close to the living body and has a biocompatibility. Among them, our SWEL developed RepRap SWIM-ER, a desktop type 3D gel printer that enables 3D free-formation of soft hydrogels. The RepRap SWIM-ER is a device that can shape the soft hydrogels into a desired shape by moving a laser pointer as the light source and irradiating the gel solution in the bathtub with ultraviolet light for photo-induced gelation. This 3D gel printer can be realized at low cost because it utilizes the results of the RepRap open source project to design the device and control it with software.

Furukawa established the “Soft 3D Co-creation Consortium” (URL: https://soft3d-c.jp) in April 2018. Considering the members of this consortium as test users, we will provide a desktop type 3D gel printer RepRap SWIM-ER. First, in the field of research and development, we will use the 3D printing of soft hydrogel materials and share the practical use cases among the consortium members At the same time, we are planning to standardize the several methods concerning both the material design of 3D gel printers and the evaluation of shaped objects.

Figure 1
(Invited) Scanning Microscopic Light Scattering with Machine Learning for Quality Assurance of 3D-Printed Hydrogels
Authors: Furukawa Hidemitsu , Ogawa Jun , Watanabe Yosuke , Shiblee MD Nahin Islam , Khosla Ajit , Kawakami Masaru
Published: December 2020

Scanning microscopic light scattering (SMILS) is a powerful tool for the characterization of soft and wet matter, including polymer gels, polymer solutions, and the dispersion of nanometer particles. Specially the SMILS has a special advantage to overcome the inhomogenities of the soft and wet matter. For example, the network structure of polymer gels is so stable that the inhomogenities due to the fluctuation under the formation of chemical reaction, i.e. gelation, tends to be fixed in the network structure. This kind of the static inhomogeneites causes the position dependence of the observation of the polymer gels in the experiment of light scattering. The SMILS is able to scan the sample of the soft and wet matter and observes many data in different positions in the same sample to obtain the space-averaged data of the time-averaged correlation functions of scattered photons. Then the SMILS determine the ensemble-averaged correlation function.

However, through the actual experiences of the SMILS experiments, we knew that the set of many data in different positions has several bad data due to dust, stray light, and mechanical vibration. By thinning the set of data to remove the bad data, the net result of the ensemble-averaged correlation function tends to improve very well. In the previous studies, we sometimes obtained the 30-100 data in different positions and thinned out the data to remove the 1-70% based on the judgement of the observer. There is a problem that the thinned data may depend on the observer.

To overcome this problem, we tried to apply machine learning for the SMILS experiments. In the machine-learning procedure, artificial intelligence was made to learn the thinning operation of the observer as a teacher so that the same thinning operation as the observer could be performed. The below-shown figure shows one of the results of this procedure. It is shown that the raw ensemble-averaged correlation function has the ambiguous four peaks of relaxation modes. However the thinned correlation function by the machine-learning procedure will improve and show only one nice-seeming peak. We will exam the reliability of this novel automation procedure especially for the 3D-printed hydrogel samples and will establish the novel AI-aimed SMILS system to be applied for quality assurance of 3D-printed hydrogels in near future.

Figure 1
(Invited) 3D Printing of Polymer Composite Electrolytes for Li Batteries
Authors: Shahbazian-Yassar Reza
Published: December 2020

Polymer-based batteries offer new opportunities to transform the traditional manufacturing of Li ion batteries. This presentation provides an overview on efforts in the PI's lab to manufacture thermally safe and high energy density batteries using 3D printing techniques. In the first part of this presentation, I will showcase our 3D printing work for PVDF-based polymer electrolytes reinforced with TiO2 nanoparticles. We utilized elevated temperature printing technique to avoid the use of solvents that are often detrimental to the final printed structures due to the need for their evaporation resulting in shrinkage and structural collapse. We controlled the mechanical properties and shear properties of our electrolytes by controlling the concentration of TiO2 and use of ionic liquids to achieve 3D printing. The printed electrolyte make strong adhesion with the electrode material evidenced by low interfacial resistance across the electrode-electrolyte interface. The printed full batteries demonstrated successful cycling indicating of their potential for high cycle applications. In addition, we developed PEO-based polymer electrolytes reinforced with 2D materials in order to control the rheological properties of the ink electrolyte. The printed structures showed better thermal management indicating that the alignment of 2D materials can be an effective approach to control the printing of polymer batteries.
(Invited) 3D Printing and Wireless Power Transfer Systems for Soft Robotics Applications
Authors: Oruganti Sai Kiran , Khosla Ajit
Published: December 2020

Wireless power transfer (WPT) to electrical and electronic systems is an attractive substitute to conductor wiring [1]. The problem of delivery of power to multiple sensors in an environment is well known. The conductors of these power supplies are susceptible to breakage, short circuit, electronic signal cross talk, among others [2]. Perhaps a major challenge would be in the area of soft robotics, where flexible sensors are desired. In these areas a physical wiring is going to compromise the physical flexibility of the sensors. A free positioning WPT system is going to allow the necessary flexibility as there is no physical conductor and the transceivers need not be perfectly aligned for efficient delivery of power[3].

References

[1] S. K. Oruganti and F. Bien, "Flexible wireless energy transfer systems by carbon fiber as a dielectric material: Study and experiments," 2013 IEEE Wireless Power Transfer (WPT), Perugia, 2013, pp. 159-162, doi: 10.1109/WPT.2013.6556907.

[2] S. K. Oruganti, O. Kaiyrakhmet and F. Bien, "Wireless power and data transfer system for internet of things over metal walls and metal shielded environments," 2016 URSI Asia-Pacific Radio Science Conference (URSI AP-RASC), Seoul, 2016, pp. 318-320, doi: 10.1109/URSIAP-RASC.2016.7601321.

[3] Oruganti, S.K., Liu, F., Paul, D. et al. Experimental Realization of Zenneck Type Wave-based Non-Radiative, Non-Coupled Wireless Power Transmission. Sci Rep 10, 925 (2020). https://doi.org/10.1038/s41598-020-57554-1
2D and 3D Control of Lipid Bilayer Membranes for Molecular Sensors
Authors: Yoshida Kazunari , Mitsumori Ryohei , Horii Keitaro , Takashima Akito , Nishio Izumi
Published: December 2020

The lipid bilayer structure is the main component of cell membranes, therefore, the physical properties of such structure have been studied for many years. Recently, the applications of lipid bilayers have been studied, in addition to fundamental studies. For instance, a transistor-like device was developed (Ma et al., ACS Omega, 2019).

As a part of such studies, we show the 2D and 3D control of lipid bilayer membranes. The first one is the effect of local anesthetics, Dibucaine hydrochloride molecules, on the phase behavior of ternary lipid membranes, which corresponds to the 2D control of lipid bilayer membranes (Yoshida et al., MedChemComm, 2015). The lipid membranes composed of a saturated phospholipid, unsaturated phospholipid, and cholesterol induce lateral phase separation. We revealed that the phase behavior is affected by the insertion of local anesthetic molecules into bilayer structures. Another one is the effect of toxic polar molecules, acetonitrile molecules, on the shape of lipid bilayer vesicles, which corresponds to the 3D control of lipid bilayer membranes (Yoshida et al., Colloids Interfaces, 2018). Insertion of acetonitrile molecules induces the membrane deformation.

We are trying to utilize such behaviors for soft and bio-inspired molecular sensors. We show the trials for such applications.
Diuranium(IV) Carbide Cluster U2C2 Stabilized inside Fullerene Cages
Authors: Abella Guzman Laura
Published: December 2020

Novel actinide cluster fullerenes, U2C2@I
h(7)-C80 and U2C2@D
3h(5)-C78, were synthesized and fully characterized by mass spectrometry, single crystal X-ray crystallography, UV-vis-NIR , Raman spectroscopy, IR spectroscopy, as well as density functional and multireference wavefunction calculations. The encapsulated U2C2 is the first example of a uranium carbide cluster featuring two U centers bridged by a C≡C unit. The U-C bond distances in these U2C2 clusters are in the range between 2.130-2.421 Å. While the U2C2cluster in U2C2@C80 adopts a butterfly-shaped geometry with a U-C2-U dihedral angle of 112.716 °and a U-U distance of 3.855 Å, the U-U distance in U2C2@C78 is 4.164 Å and the resulting U-C2-U dihedral angle is increased to 149.084 °. The combined experimental and quantum-chemical results suggest that the formal U oxidation state is +IV in the U2C2 cluster, and each U center transfers three electrons to the C2n cage and one electron to C2. Different from the strong U=C covalent bonding reported for U2C@C80, the U-C bonds in U2C2 are less covalent and predominantly ionic. The C-C triple bond is somewhat weaker than in HCCH and the C-C
-bonds undergo donation bonding with the U centers. This study demonstrates that the combination of the unique encapsulation effect of fullerene cages and the variable oxidation states of actinide elements can lead to the stabilization of novel actinide clusters which are not accessible by conventional synthetic methods.

Figure 1
Utilization of Hard Carbon As a Substitute for Graphite As Efficient Lithium Battery Anode Material
Authors: Dada Oluwaseun John
Published: December 2020

Lithium battery anode plates were made from sugar processed into hard carbon by high temperature carbonization in an autoclave. Sucrose was dissolved in water at 60 ⁰C, mixed thereafter with naphthalene. The hard carbon is purifies with HCl and distilled water. Nano-hard carbons1,2 are 3-dimensional and notably larger than the 2-dimensional graphenes3-5. Anode plates were prepared by homogenizing the sonicated graphene in PVDF saturated NMP (0.53% NMP; 4% super-P carbon black; and 2.25wt% PVDF) for 1 hr. The anode slurry was coated on the copper plates using automatic doctor blade film coater at a speed of 100mm/min. Anode plates were dried at 80 ⁰C for and cured for 120 ⁰C for 2 hrs and 24 hrs respectively, in vacuum oven. Coin cells of NMC//HC were made and tested in CT2001A. The capacity of 48 µm thick and 28.2 g/m2 anode cycled at 1C was ~49.70 mAhg-1, which is a replaceable anode material for lithium-ion batteries to 67 µm thick and 33.9 g/m2 graphite anode with a capacity of 60.62 mAhg-1.
Au/Cdots Nanohybrids As Efficient Electro-Catalysts for Hydrogen Evolution Reaction
Authors: Nguyen Ngoc Anh , Nguyen Van-Toan , Ngo Quang-Tung , Trinh Van-Huy , Choi Ho Suk
Published: December 2020

In this study, we report a facile method to synthesize carbon dots (Cdots) from rice straw and then use it as a directly reducing agent as well as a stabilizer to produce Au@Cdots nanohybrids. Rice straw-derived Cdots possesses oxygenated groups, which act as an electron-donating source to reduce Au3+ to Au0. The strong Au-carbon interaction propels a high electron transfer for Au@Cdots electrocatalyst towards enhanced-performance in hydrogen evolution reaction (HER). When Au@Cdots electrocatalyst is used for the HER process, the HER activity is maintained stable for 2000 cycles. The overpotential is 150 mV at a current density of 10 mA.cm-2, which is the outstanding HER performance for Au nanohybrids as a non-Pt HER electrocatalyst.
Durability of Graphene-Supported Iron Phthalocyanine in Acidic and Basic Media: A Theoretical Study
Authors: Orellana Walter , Tasca Federico
Published: December 2020

The oxygen reduction reaction (ORR) is a crucial chemical process, which contributes significantly to the energy efficiency of fuel cells and metal-air batteries. Although Pt and its alloys are known as the most efficient catalysts for ORR, its high costs and scarcity limits their applications. Alternatively, Fe–N–C catalysts have attracted the most interest owing to their low-cost and facile preparation methods. Metal macrocycles, such as iron phthalocyanines (FePc), are the precursors most widely used to prepare the ORR catalysts in fuel cells and metal-air batteries. However, limited progress has been made in improving their electrocatalytic activity and durability. In particular, FePc has demonstrated to suffer from severe degradation in the acidic fuel cell environments, commonly attributed to demetalation and/or degradation by ORR intermediates. The typical life cycle for FePc catalysts is less than 100 cycles in either acidic or basic media.

In this work we use ab initio molecular dynamic (MD) simulations to investigate the degradation of graphene-supported FePc in acidic and basic media at operational conditions. The acidic media includes hydrochloric, acetic, sulfuric and phosphoric acids, whereas the basic media includes sodium hydroxide. The solution concentration in all cases is 1M. The MD simulations were performed by dispersion-corrected DFT calculations, using periodic boundary conditions, at 80°C through a simulation time of 2 ps. Our results show that demetalation is not the cause of the FePc degradation, instead we find that for acetic and hydrochloric acids, the acid anion binds to the Fe center, with binding energies of -1.1 and -6.5 eV, respectively. The formation of this ligand would hinder the O2 adsorption on the metal center, limiting the FePc catalytic activity. On the contrary, for phosphoric and sulfuric acids, as well as for basic media, the ion-Fe binding is energetically unlikely, enabling the O2-metal interaction. Therefore, our results suggest that the catalytic activity and degradation of FePc are connected to the acidic media involved.

This work was supported by ANID/FONDECYT under Grant No. 1170480
Synthesis and Characterization of Nanocrystalline Boron-Doped Diamond Electrodes: Towards Electrochemical Reduction of CO2
Authors: Ashcheulov Petr , Hak Ondrej , Taylor Andrew , Davydova Marina , More-Chevalier Joris , Mortet Vincent
Published: December 2020

The continuous increase of atmospheric carbon dioxide (CO2) concentration along with pollution of waters by organic wastes have led the scientific community to investigate novel strategies to address these worldwide environmental problem. Electrochemical methods are a promising approach to convert CO2 into a variety of useful chemicals and to remove contaminants from wastewater [1,2]. Nevertheless, it is necessary to develop inexpensive and chemically robust electrodes with long life-time in harsh electrochemical conditions for these processes to be efficient and economically viable.

Boron-doped diamond (BDD) has been recently shown to be a promising material for electrochemical reduction of CO2 into formic acid and formaldehyde [3]. In contrast to thick microcrystalline BDD films, thin nanocrystalline BDD layers (thickness of 100 - 500 nm) provide a higher degree of flexibility in material properties, e.g. due to a variable diamond/non-diamond content, and allows efficient bottom-up nanostructuring, e.g. BDD growth on porous templates [4].

In this work, we investigate nanocrystalline boron-doped diamond and composite BDD/SiC electrodes synthesized via microwave plasma enhanced chemical vapor deposition (MW PE CVD) method at different deposition temperatures (250 - 750°C) towards electrochemical reduction of CO2 in water-based electrolytes [5]. Fabricated electrodes were characterized by a variety of techniques, including Raman spectroscopy, scanning electron microscopy imaging and electrical conductivity measurements. Electrochemical properties of nanocrystalline BDD electrodes of various thickness, boron content and electrical conductivity were studied.

This work has been supported by the Grant Agency of the Czech Republic (GACR) contract 19-09784Y.

[1] I. Sirés et al., Environ Sci Pollut Res (2014) 21: 8336.

[2] A. Goeppert et al., Chem. Soc. Rev. (2014), 43, 7995-8048.

[3] K. Nakata et al., Angew. Chem. Int. Ed. (2014), 53, 871 –874.

[4] V Petrák et al., Carbon (2017), 114, 457.

[5] A. Taylor et al., J. Alloys. Compd., (2019) 800, 327-333
Cost-Effective and Eco-Friendly Carbon-Based Nanomaterials in Wearable Energy Storage Devices
Authors: Das Himadri Tanaya
Published: December 2020

The growing concerns of pollution and subsequent climate change have garnered researchers and enthusiasts all over the world to strive forward towards a sustainable and renewable energy economy. Nevertheless the energy production is not sufficient enough until, it is stored and utilised adequately. Henceforth, the electrochemical energy storage devices such batteries and supercapacitors have find a prominent place in the list. Quite recently, wearable energy storage devices can be a game changing for the energy storage industries. Thus, the search of competent electrodes for potential device is incalculable. The nanomaterials based electrodes are attracting the interest of scientist because of their efficient capacity in energy storage.

In the nanomaterials, the physical and chemical properties can be extensively tuned by parameters such as morphology, distributions, composites etc. Besides that the electrolyte in an energy storage device also plays a vital role for the operating potential and cycle life of the device. The conductive electrolyte provides pathway for easy ion movements during charge and discharge of device. The carbon-based nanomaterials such as graphene, carbon quantum dots, activated carbon etc., can be used as negative electrode. These can be also used as positive electrodes when composite with some metal oxides, hydroxides or sulphides. These electrode materials can be synthesised by chemical methods or by carbonising the natural products such as dry leaves, fruits, peals, milk etc. Most interesting process to extract carbon is recycling the wastes viz., tyres, shoot, dry cells etc. to have an eco-friendly environment. Thus realize highly stable device, the development of carbon-based electrode materials is imperative. In this work, generation of efficient carbon-based electrodes by recycling of waste for energy storage devices will be presented in details.

The wearable energy storage devices are emerging area for future electronics technology. Wearables are not just a smartwatch, but a whole range of wearable devices, including biosensors, biomedical equipment, renewable charged devices etc. These devices have tremendous potential to improve quality of life and safety. Researchers and industries are involved in developing carbon-based electrodes for wearable sensors and self-powered devices to create a new generation of wearables with high outcomes to meet the consumer demand. Henceforth, the generated carbon-based materials can be potential electrodes in wearable energy storage devices.

Key words: Nanomaterials, Recycling, Carbon, Energy, Wearable Electronics, Capacity
Corrosion Enhancement of the AISI 304 Stainless Steel Using a High Power Diode Laser and Large Pulsed Electron Beam
Authors: Park Hyung Wook
Published: December 2020

The large pulsed electron beam (LPEB) has been widely used for surface modification of metals, alloys, polymers and composites due to its unique interaction mechanisms with materials. Especially for metals, it can simultaneously improve mechanical characteristics and chemical stabilities during rapid melting and re-solidification processes inducing a phase transformation at the re-solidified layer. However, generation of craters has been reported to adversely affect surface quality. It is important to reduce the craters following the LPEB irradiation for the effective protection of pitting corrosion on the surface of stainless steels. In this study, a hybrid surface modification method using a high power diode laser (HPDL) and LPEB is proposed to reduce the generation of craters during the LPEB irradiations. The size and density of craters generated during the LPEB irradiations were effectively reduced following the hybrid surface treatment using HPDL. The corrosion resistance was significantly improved by reducing craters and phase transformation. The passive region on the re-solidified layer after the HPDL-assisted LPEB irradiation showed much wider range comparing to the bare surface of stainless steels. Furthermore, the pitting potential was also significantly modified from less than 0 mV/SCE to over 800 mV/SCE following the hybrid irradiations. After the corrosion tests, the depth of corroded pits was also significantly reduced by 75 % after the hybrid surface modification. To conclude, the HPDL-assisted LPEB irradiation has resulted in superior surface profile and improved pitting corrosion resistance as well as the general corrosion resistance following the elimination of non-metallic inclusions on the surface.
Reduction Behavior of Rusted Carbon Steel in Metallic Cation-Containing Solutions
Authors: Omoto Atsushi , Tsuchiya Hiroaki , Hanaki Koushu , Yamashita Masato , Fujimoto Shinji
Published: December 2020

In Japan, huge infrastructures such as bridges and pipelines have been built, especially since high economic growth period in 1960s. For such infrastructures, carbon steel has been extensively used due to the superior mechanical properties as well as low cost. However, as carbon steel easily corrodes in most atmospheric environments, various countermeasures against atmospheric corrosion have been proposed and carried out. It is well-known that atmospheric corrosion proceeds by repeated processes of the cathodic reaction of FeOOH to magnetite and the air oxidation of formed magnetite. The repeated processes enhance the cathodic reaction, accelerating an anodic dissolution of underlying steel. Therefore, suppressed reduction of FeOOH is expected to result in suppressed corrosion reaction on carbon steel. In our previous work, a simple immersion of rusted steels in metallic cation containing solutions was found to modify the structures of rusts on carbon steel, leading to drastic decrease in corrosion rate. The present work reports effects of metallic cations on reduction behavior of rusts grown on carbon steel.
Atomic-Scale Coordination Effects on the Initial Stage of Passive Film Formation in Fe-Cr Alloys
Authors: Xie Yusi , Liu Minglu , Aeillo Ashlee , Sieradzki Karl
Published: December 2020

The self-healing passivation behavior Fe-Cr alloys serve as a model for the development of corrosion resistant alloys and coatings. Both first principles-based calculations [1,2], neutron scattering [3] and Mössbauer spectroscopy [4] studies demonstrated that in FepCr1-p alloys, the atomic-scale distribution of Cr atoms in the BCC lattice depends on both composition and thermal history. These studies showed that there is an inversion in the Warren Cowley short range order (SRO) parameter [5] that occurs for 1-p ≅ 0.11 At. Cr compositions, less than this value, the alloys show a tendency toward ordering while at higher Cr compositions the alloys show a tendency for clustering. In terms of a simple regular solution model, this behavior is determined by the interaction parameter, ΔE = [EFe-Cr - 1/2(EFe-Fe + ECr-Cr)], where the E’s are nearest neighbor bond energies taken to be negative. Then for ΔE < 0 the system tends to short-range order, while for ΔE > 0, clustering behavior is expected. In order to study these atomic scale coordination effects on passivation, FepCr1-p alloys were heat-treated according to the protocols used in the neutron scattering and Mössbauer spectroscopy studies. The behaviors of these alloys were compared to that of their random solid solution counterparts. Linear sweep voltammetry and chronoamperometry were used to characterize the initial stage of passivation in these two sets of alloys. Our results reveal some subtle yet significant differences in their passivation behaviors [6]. These results are interpreted within the context of the percolation conjecture suggested by Sieradzki and Newman [7].

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Corrosion of AISI 310 and 316 in Molten Hydroxide Under Steam Electrolysis Conditions
Authors: Anisur M.R. , Aphale Ashish N , Dubey Pawan Kumar , Hong Junsung , Reisert Michael , Singh Raman R K , Heo Su Jeong , Patil Kailash , Xu Hui , Yuh Chao-Yi , Singh Prabhakar
Published: December 2020

Steam electrolyzers, utilizing molten hydroxide electrolyte, offer potential for improvement in electrochemical efficiency, cost reduction, use of conventional materials of construction and process scale up for large scale hydrogen production. Stainless steels, used for the fabrication of cell components (current collector, gas separator, wet seals, and manifolds) experience accelerated corrosion in the presence of molten hydroxide electrolyte in both oxidizing (anodic) and reducing (cathodic) atmospheres. In this study, the corrosion behavior of AISI 310 and 316 has been studied at 600 °C using melt immersion and cyclic voltammetry tests. Melt immersion test revealed formation of the porous lithium iron oxide at the melt-oxide interface for both AISI 310 and 316. Oxide scale cross-sectional study conducted by FIB/TEM showed multi-layer oxide scale formation. Inductively Coupled Plasma (ICP) Spectroscopy analysis showed the presence of Cr in the electrolyte melt obtained from samples exposed to oxidizing atmosphere. Cyclic voltammetry tests showed the breakdown of passive metal-oxide under anodic overpotential in molten hydroxide. Mechanisms for hydroxide-induced corrosion is proposed and discussed.
Understanding the Structure and Speciation of Molten LiCl-KCl Using Raman and Ultraviolet-Visible-Near IR Spectroscopic Techniques
Authors: Moon Jeremy , Phillips William C. , Gakhar Ruchi , Chidambaram Dev
Published: December 2020

Pyrochemical reprocessing (pyroprocessing) of used nuclear fuel (UNF) is a promising pathway towards closing the nuclear fuel cycle by recycling actinides into new fuel and providing the means to generate durable wasteforms for portions of the UNF that are not able to be recycled. One of the most significant challenges in the advancement of this technology is developing a more complete understanding of the chemistry of the electrolyte molten salts used in the electrorefining process, where fission products, transuranic elements and fuel elements are anodically dissolved into a LiCl-KCl electrolyte, forming a chemically complex mixture. To enhance our understanding of the chemistry of the mixture of molten salt electrolyte and UNF we are studying the structure and speciation of lanthanide and actinide elements dissolved in LiCl-KCl using Raman and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. These techniques are starting to provide information on the coordination, symmetry, and electronic structure of the dissolved species, which will result in a more complete understanding of the chemistry of these solutions. Results of a Raman spectroscopy study of mixtures of NdCl3, SmCl3, CeCl3, and EuCl3 with LiCl-KCl and LiCl-KCl-UCl3 and the development of a system to conduct Raman and UV-Vis-NIR spectroscopy and spectroelectrochemistry will be presented.

Acknowledgements: This work was performed under the auspices of the Department of Energy (DOE) under contracts DE-NE0008889, and the US Nuclear Regulatory Commission (NRC) under contracts NRC-HQ-13-G-38-0027 and 31310018M0032. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively. For support of furnace design and fabrication work at INL, RG and WCP acknowledge the Laboratory Directed Research & Development (LDRD) Program under DOE Idaho Operations Office Contract DE-AC07-05ID14517 and a subcontract under LDRD (INL) to University of Nevada, Reno via award number 204471 (UNR award AWD-01-00001719); this design served as starting iteration for this work. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1447692. One of the authors, JM, acknowledges the Graduate Research Fellowship from the US National Science Foundation.
Studying Proton Conducting Ceramic Electrolyte Stability with in Situ Raman Spectroscopy
Authors: Welander Märtha , Goettlich Daniel M. , Henning Tanner J. , Walker Robert A.
Published: December 2020

Ceramic-based proton conducting fuel cells (PCFCs) are attractive devices for directly converting chemical energy to electrical energy. Like conventional solid oxide fuel cells (SOFCs), PCFCs are fuel flexible and efficient. Because PCFC electrolytes conduct protons rather than oxides, these devices can function between 400˚C and 600˚C, temperatures that are much lower than the ≥700˚C required for SOFC operation. PCFC technology remains relatively new, however, meaning that fundamental questions about electrochemical redox mechanisms, material compatibility and device resilience must be answered before PCFCs become a viable technology for commercial development.

In this work, we use in situ vibrational Raman spectroscopy and ex situ XPS to examine the chemical stability of yttria-stabilized barium zirconate (BZY) and ceria doped BZY (BZCY) – both common PCFC electrolytes – as a function of temperature and chemical stress. In particular, in situ Raman data show that electrolyte surface and near surface composition is sensitive to steam in reducing environments with new features appearing in vibrational spectra. (The reducing environment consisted of 25% H2 in Ar; all humidified conditions included 3% H2O from running the incident gas(es) through a room temperature bubbler.) Spectral changes indicate that that the electrolyte structure and/or composition is changing on the electrolyte surface and in the near surface region (as defined by the penetration depth of the incident Raman excitation light). These changes are reversible and vibrational spectra return to their original appearance when steam is removed from the reducing atmosphere. Two important points to note are 1) new spectral features only appear within a limited temperature window between 300˚C and 450˚C and 2) new spectral features do not appear when the ambient atmosphere is inert (Ar), inert with steam (Ar with 3% H2O), or simply a reducing atmosphere (H2 in Ar). While spectral changes are reversible, the steam-altered electrolytes can be isolated by quickly cooling materials showing extraneous vibrational features back to room temperature under a humidified environment. This ability allows for additional ex situ analysis using conventional surface science methods. XPS data suggest that humidified H2 leads to enhanced Ba content on the electrolyte surface raising interesting questions about the role(s) played by surface segregation and secondary phase formation on the catalytic activity and charge transport properties of PCFC electrolytes.
High Temperature Corrosion Resistance in Molten Salts in Solar Power Concentration Plants: High Temperature Corrosión Monitoring in Dynamic and Static Conditions
Authors: Lasanta Maria Isabel , De Miguel Maria teresa , Garcia Martin Gustavo , Illana Andrea , Perez Trujillo Francisco Javier
Published: December 2020

The actual technology for solar power plants-CSP have termal storage system composed by molten salts. Molten salts technology means electrochemical electrolytes in contact with materials, and in this case high temperature molten salts. which are an ionic electrolyte. In order to follow up the evolution of the sal chemistry, i.e. concentrating the impurities such as chlorides and sulphates, and to monitor the corrosión rate and corrosión mechanism of structural materials, electrochemical sensors have been developed and patented. On the other hand, in order to check the reliabilify and performance of the sensors, static and dynamic test have been performed in a pilot plant.

Moreover, his study assessed the behaviour of a constructive material in CSP plants, namely ferritic-martensitic steel, with molten NaNO3/KNO3 (60/40 wt%), also known as Solar Salt. To this end, EIS is presented as a suitable technique to evaluate and monitor the resistance of this material to Solar Salt at 580 °C. Tests were performed up to 1000 h and results were also supported by gravimetric and microstructural characterisation of the samples and chemical analysis of the salt. According to the EIS results, a diffusion-controlled reaction occurred during contact, which indicates that the corrosion process follows a porous layer mechanism. The results also indicated variations in corrosion layer thickness and instability of the salt during the whole test. The EIS results were also used for determining the corrosion rate, this being estimated at ~300 µm year−1. Results obtained by EIS were in line with the behaviour of P91 steel as measured by gravimetric, morphological and chemical analysis. Thus, the results confirm the suitability of EIS for monitoring corrosion processes in real-time of constructive materials in CSP plants.
Approximate Analytical Solution of One-Dimensional Beam Equations by Using Time-Fractional Reduced Differential Transform Method
Authors: Yadeta Dessalegn Mekonnen , Gizaw Ademe Kebede , Mussa Yesuf Obsie
Published: December 2020

In this paper, a recent and reliable method, named the fractional reduced differential transform method (FRDTM) is employed to solve one-dimensional time-fractional Beam equation subject to the appropriate initial conditions. This method provides the solutions very accurately and efficiently in convergent series form with easily computable coefficients. The efficacy and accuracy of this method are verified by means of three illustrative examples which indicate that the present method is very effective, simple, and easy to implement. Finally, it is observed that the FRDTM is the prevailing and convergent method for the solutions of linear and nonlinear fractional-order partial differential equations.