bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Carbon Substrate Pretreatment on the Ecsa and Activity of RhxSy/C Catalyst
Authors: Li Yuanchao , Nguyen Trung Van 
Published: February 2020

Electrical energy storage technologies are needed when significant fraction of intermittent renewable energy sources such as wind and solar are integrated into the electrical grids. The hydrogen-bromine (H2-Br2) reversible fuel cell system is one of the promising technologies because of its high round-trip conversion efficiency, high power density capability and low cost. In a hydrogen bromine fuel cell, while carbon can be used for the bromine reactions, a noble metal such as platinum is needed for the hydrogen reactions. Since platinum is not stable in HBr/Br2 environment and HBr and Br2 are expected to cross from the bromine electrode to the hydrogen electrode during operation, a more durable and active catalyst is needed for the hydrogen reactions. RhxSy catalysts have been found to be stable in the HBr/Br2 environment and as active as platinum per active area. 1,2

Commercial RhxSy catalysts have large and broad particle sizes (12-40 nm) and consequently low mass specific active area (< 10 m2/g) for HOR. By literatures3,4, smaller particle size can be achieved if more preferable surface for precipitation of Rh cation is provided. Figure 1 shows the mass specific active surface area (ECSA) of the catalyst with pretreated carbon and commercial RhxSy catalysts. It shows that the RhxSy catalyst with pretreated carbon material has much higher mass specific ECSA than commercial RhxSy. This presentation will discuss the approach used to synthesis the RhxSy catalyst with pretreated carbon and the characteristics and performance of this catalyst.

Figure 1. CV of catalyst with pretreated carbon and commercial
one
, measured in 1M H2SO4 with 10 mV/s scan rate

References

1. J. Masud, T. Van Nguyen, N. Singh, E. McFarland, M. Ikenberry, K. Hohn, C. J. Pan and B. J. Hwang,,, Journal of the Electrochemical Society, 162, F455–F462 (2015).
2. A. Ivanovskaya, N. Singh, R.-F. Liu, H. Kreutzer, J. Baltrusaitis, T. Van Nguyen, H. Metiu and E. McFarland,, Langmuir, 29, 480–492 (2013).
3. A. Eguizabal, L. Uson, V. Sebastian, J. L. Hueso, and M. P. Pina, RSC Advances, 5, 90691–90697 (2015).
4. M. S. Shafeeyan, W. M. A. W. Daud, A. Houshmand, and A. Shamiri, Journal of Analytical and Applied Pyrolysis, 89, 143–151 (2010).

Acknowledgements

The work presented herein was funded by the National Science Foundation under Grant No. EFRI-1038234.

Figure 1
The Characteristics of Non-Aqueous Redox Flow Battery Using Organic Materials
Authors: Shin Kyoung-Hee , Park Se-Kook , Jin Chang-Soo , Yeon Sun-Hwa , Lee Bum suk 
Published: February 2020

The redox flow battery (RFB) has been considered to be one of the most promising electrical energy storage system with large-scale applicable, owing to its attractive features such as flexible design, high safety and high efficiency [1-3]. Despite significant advances, the operating potential of such aqueous RFBs are generally limited by the electrochemical stability window of water, and hence low energy density is obtained [4-6]. In contrast, non-aqueous RFBs have been receiving increasing interest given that non-aqueous electrolytes offer the possibility of wider potential windows. Therefore, non-aqueous RFBs have attracted considerable attention [7,8].
In this work, all-organic redox couples (metal-free organic materials) were used as a negative and a positive electrolyte, respectively. From cyclic voltammetry tests, it was confirmed that a non-aqueous redox system yielded an estimated high potential at a 50% state of charge, and electrochemical test appeared to be stable and reversible.

Reference

[1] Z. Yang, J. Zhang, M.C. Kintner-Meyer, X. Lu, D. Choi, J.P. Lemmon, J. Liu, Chem. Rev., 111 (2011) 3577-3613.
[2] B. Dunn, H. Kamath, J.-M. Tarascon, Science, 334 (2011) 928-935.
[3] C. Koroneos, T. Spachos, N. Moussiopoulos, Renewable energy, 28 (2003) 295-310.
[4] M. Skyllas-Kazacos, M. Chakrabarti, S. Hajimolana, F. Mjalli, M. Saleem, Journal of The Electrochemical Society, 158 (2011) R55-R79.
[5] A.Z. Weber, M.M. Mench, J.P. Meyers, P.N. Ross, J.T. Gostick, Q. Liu, Journal of Applied Electrochemistry, 41 (2011) 1137-1164.
[6] P. Leung, X. Li, C.P. De León, L. Berlouis, C.J. Low, F.C. Walsh, Rsc Advances, 2 (2012) 10125-10156.
[7] J. Mun, M.-J. Lee, J.-W. Park, D.-J. Oh, D.-Y. Lee, S.-G. Doo, Electrochem. Solid-State Lett., 15 (2012) A80.
[8] Z. Li, S. Li, S. Liu, K. Huang, D. Fang, F.Wang, S. Peng, Electrochem. Solid-State Lett., 14 (2011) A171.
Polyimide-Wrapped Carbon Nanotube As High Capacity and Rate Anode for Aqueous Rechargeable Na-Ion Batteries
Authors: Lim Hana , Cho Bo-Young , Lee Ho-Nyun , Lee Min-Hyung , Kim Hansung , Kim Hyun-Jong 
Published: February 2020

Rechargeable lithium-ion batteries (LIBs) are rapidly extended from portable device to electric vehicle and smart grids owing to their high energy density and long cycling life. However, its potential for large-scale applications in electric vehicles and energy storage is hampered by the high production costs and finite supply of lithium. With this background, an attractive approach to circumvent this problem is to use an aqueous electrolyte for Na-ion batteries (NIBs). Researchers hope to overcome this problem by replacing it with sodium, which is cheaper, nontoxic, and easier to process and almost infinitely abundant.
In this study, pyromellitic dianhydride (PMDA)-derived polyimide deposited on the carbon nanotubes were used as anode of aqueous electrolyte battery. That is, polyimide was directly polymerized on the surface of CNT. SEM and TEM revealed that the polyimide was homogeneously wrapped the surface of the CNTs and formed a uniform shell. This suggests that the interactions between polyimide molecules and CNTs overcame the Van der Waals interaction between CNTs, which generally otherwise would result in separate growth or aggregates of polyimide.
The charge-discharge characteristics were investigated by using 3-electrode beaker cell with 2M Na2SO4 solution. The reduction and oxidation of polyimide are accompanied by the association and disassociation of Na+ ions with oxygen as described in Fig. 1. Each formula unit is able to transfer four electrons through two steps, which may allow a high theoretical specific capacity, 280.4 mAh g-1. The polyimide-wrapped carbon nanotube exhibited much superior high-rate and long cycling performance to conventional inorganic anode. The calculation of diffusion coefficient and impedance study revealed that these high performances were attributed to the advantages of hierarchical core-shell structure. The conductive CNT core offered continuous electron transport pathways and thin polyimide shell provides rapid Na+ ion diffusion pathways. Thus, the bicontinuous electron/ion transport channel greatly facilitate the ion diffusion kinetics and reduce the charge transport resistance, resulting in the excellent rate capability.

Figure 1
(Keynote) Recent Progress in Nanoscale Understanding of Surface Oxide Film Formation, Properties and Breakdown on Metals and Alloys Using in Situ and Ex Situ Characterization Methods
Authors: Marcus Philippe 
Published: February 2020

After a short historical introduction in recognition to the pioneering work of Masahiro Seo, recent advances in the understanding at the nanoscale of the formation, properties and breakdown of oxide films on metals and alloys will be presented, with emphasis on data obtained using advanced in situ and ex situ surface analytical techniques such as Scanning Tunneling Microscopy (STM), Scanning Tunneling Spectroscopy (STS),Current-Sensing Atomic Force Microscopy (CS-AFM), X-ray Photoelectron Spectroscopy (XPS), and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), combined with electrochemical measurements, and complemented by atomistic modelling with Density Functional Theory (DFT).
The following topics will be addressed:

Nanostructured oxide layers formed by controlled thermal oxidation of copper single crystal surfaces

Passive oxide films for corrosion protection of metals and alloys: crystallinity, oxide/metal epitaxy, effects of time of polarization on oxide crystallinity, compositional heterogeneity of surface oxides (in the case of stainless steel)

Role of surface oxide defects in passivity breakdown and initiation of localized corrosion, investigated with high resolution

Oxide layers deposited by ALD (Atomic Layer Deposition) for corrosion protection, and as model systems for the study of conversion-deconversion mechanisms in Li-ion batteries

Atomistic modelling of oxide layers on metals using density functional theory (DFT)
3D Impedance Spectroscopy: Analysis of Formation of Chromate Film
Authors: Hoshi Yoshinao , Endo Yuta , Shitanda Isao , Itagaki Masayuki 
Published: February 2020

A chromate conversion coating (CCC) shows the high corrosion resistance and improves the paint adhesion of the base metal[1-4]. It is well known that the scratch or defect in the CCC is protected without further treatment due to the self-healing effect of CCC[2]. We applied a three-dimensional (3D) impedance spectroscopy[5-7] to investigation of the self-healing effect of the chromate film formed on a steel. It is possible to obtain the film resistance with time information because the impedance was plotted on the 3D diagram whose axes are real, imaginary and time. In the present study, the scratched electrodes were used for the 3D impedance measurement in order to investigate the self-hearing effect of the chromate film. The instantaneous impedance was determined at arbitrary time from 3D impedance plot. The film resistance R
df of each electrode was estimated by the curve fitting of the instantaneous impedance with using the equivalent circuit. The increasing rate of R
df until steady state condition was determined precisely.
References:
[1] J.R. Waldrop, M.W. Kendig, J. Electrochem. Soc, 145 (1998) L11-L13.
[2] L. Xia, R.L. McCreery, J. Electrochem. Soc, 145 (1998) 3083-3089.
[3] O. Lunder, J.C. Walmsley, P. Mack, K. Nisancioglu, Corros. Sci., 47 (2005) 1604-1624.
[4] A.S. Hamdy, I. Doench, H. Mohwald, Thin Solid Films, 520 (2011) 1668-1678.
[5] Z. B. Stoynov, B. S. Savova – Stoynov, J. Electroanal. Chem., 183 (1985) 133.
[6] M. Itagaki, N. Kobari, S. Yotsuda, K. Watanabe, S. Kinoshita, M. Ue, J. Power Sources, 135 (2004) 55-261.
[7] M. Itagaki, K. Honda, Y. Hoshi, I. Shitanda, J. Electroanal. Chem. 737 (2015) 78-84.
(Invited) Passivity and Localized Corrosion of Stainless Steels in Energy-Related Applications
Authors: Virtanen Sannakaisa 
Published: February 2020

In recent years, new types of environments related to energy technologies can provide new challenges for the passivity of traditional materials. Examples are different types of biofuels (ethanol, ethanol-gasoline blends, biodiesel). For instance, stress-corrosion cracking of steels can take place in ethanolic environments and Al alloys can show very fast degradation in ethanol-containing fuels at higher temperatures.
This presentation will focus on passivity and localized corrosion of stainless steels in such new type of environments. Critical factors of localized corrosion were studied in different ethanol-gasoline blends, in presence of various corrosion-enhancing factors (such as H2O, chloride contamination). The influence of the different factors on occurrence of pitting corrosion and the morphology of growing pits was studied. In addition, XPS measurements were carried out, to explore the effect of the specific environment on the nature of the passive films.
Other examples of the behavior of stainless steels in energy-related applications will be shortly discussed, such as passivity and localized corrosion in molten salts that can be used as heat transfer media in high temperarature applications.
Thin Metal Oxide Coatings for Lightweight Alloys
Authors: Sammelselg Väino , Merisalu Maido , Aarik Lauri 
Published: February 2020

A new type of nanocomposite coating and its preparation technology was worked out1 and will be introduced in this presentation. The technology has two main steps – first, the working surface of substrate is anodized and second, the anodized base layer is covered with a thin toplayer, grown by atomic layer deposition method (ALD). Both steps of the coating preparation need special attention. The anodizing of a lightweight substrate, e.g. an aluminum alloy must result in a homogeneous by both thickness and composition anodic layer, and must consist as little as possible cracks and pores. It is well known that the anodic layer consist nanometric pores and at least part of them is reaching the substrate metal part and these are the weakest points of the anodized coating. Thus, the pores must be firmly sealed and even better filled up to the bottom with a corrosion resistant material. This can be achieved with the help of ALD that is a cyclic analogue of chemical vapor deposition method. In the presentation we will demonstrate how the new coating is prepared for Al2024 alloy, which is tending to pitting corrosion due to existing in it Cu-rich and other intermetallic particles, often with micrometer dimensions, part of them laying in near-surface region of the substrate.
In the presentation we will go through the substrate surface pretreatment, anodizing and following ALD growth of nanolaminate of metal oxides as top part of the coating. The process gives micron thick composed coating with filled nanopores, see the scheme, and that coating withstand several thousand hours’ immersion in salt solution. Similar technique was used for protection Ti5 alloy substrates.
In the presentation will be discussed surface pretreatment, anodizing and following ALD process, which gives micron thick composed coating with filled nanopores, see the scheme, and which withstand several thousand hours’ immersion in salt solution. Similar technique was used for protection Ti5 alloy substrates.
In the presentation will be discussed surface pretreatment, anodizing and following ALD process, which gives micron thick composed coating with filled nanopores, see the scheme, and which withstand several thousand hours’ immersion in salt solution. Similar technique was used for protection Ti5 alloy substrates.

L. A. thanks the European Social Funds of Doctoral Studies This work was also supported by the Estonian ME&S by projects IUT2-24, TK117 and TK141.

Reference:

V. Sammelselg, M. Merisalu, L. Aarik, Method of preparing corrosion resistant coatings, WO 2014102758 A1/GB2509335 A, Priority date 31.12.2012 (http://www.google.com/patents/WO2014102758A1?cl=en).

Figure 1
An Investigation into the Stability of Passive Layers on Zinc Under Alkaline Conditions
Authors: Cole Ivan Stuart , Veluchamy Angathevar , Bosco Emmanuel 
Published: February 2020

The paper investigates the passivity of zinc as a function of applied potential and chloride concentration. The paper reports primarily on passivation in alkali solution as determined by potentiostatic holds but potentiostatic polarization ( at 1mV/sec) in a borate buffer were carried out to determine appropriate conditions for the holds. Potentiostatic holds (for 104 sec) at 1.05, 0.8, 0.55, 0.3, 0.05, -0.2, and -0.45Vsce were undertaken in a borate buffer (pH = 9.5) with varying chloride concentration . Two patterns of variation of current with time were observed with the holds, in the first (type1) the current rapidly decreased to low levels , then after some time transients with high current occurred, followed by a return to stable low currents . In the second (type2) once again there was an initial decrease in current but after the transient the current rose to high values. In a further series of tests at a potential (+1.05Vsce) with different chloride ion concentration added at 10000th sec. Again type 1 and type 2 behavior’s where observed with the addition of low levels of chloride resulted in type1 behavior and the higher in type 2. The relevance of the results to an understanding of the stability of zinc oxide films is discussed.
Evaluation of Zn Doped Hydroxyapatite Plasma Spray Biocompatible Coatings on Metallic Substrates
Authors: Take Seisho , Kato Masataka , Asami Tomoya , Aihara Yuto , Izawa Satoru , Atsumi Taro 
Published: February 2020

In a super-aged society such as Japan, needs for new type implants which has both excellent biocompatibility and high functionality are increasing. Hydroxyapatite (HAp) is known to be very biocompatible since it is the main inorganic content of human tooth and bones. The development of HAp plasma spray coating on metallic substrate has been engaged by our lab and other researchers. In this study, Zn doped HAp plasma coatings on Ti and SUS316L were prepared by using Zn doped HAp powder obtained by high temperature sintering of the mixture of ZnO and HAp. The credibility, the functionality and the adhesion were investigated by electrochemical impedance measurements, ICP analysis and two types of adhesion tests. After the mixture of ZnO and HAp was sintered at 1150˚C for 10 hours, ZnO X-ray diffraction peaks reduced greatly. Also, the lattice constants of HAp changed with the change of ZnO percentage in the mixture meaning most Zn2+ ions were embedded into the crystal structure of HAp. Long-term credibility evaluation for Zn doped HAp plasma spray coatings in SUS316L was conducted by electrochemical impedance measurements. The results of impedance results showed that corrosion resistance for coatings with post heat treatment kept in a very high value during 12 weeks immersion in Hanks solution, indicating the post heat treatment improved the stability of Zn doped HAp coatings in SUS316L by changing the coating from amorphous structure to a crystalized one. The results from ICP analysis also proved the higher stability achieved by post heat treatment. The dissolution of Zn2+ ions was detected in Hanks solution which implies the possibility of stimulation to the bone growth. The adhesion evaluation was done by three-points bending test and a standard ASTM adhesion test for Zn doped HAp plasma spray coatings on Ti. Zn doped HAp coatings showed strong adhesion to the metallic substrate. The residual stress in coatings was investigated by x-ray diffraction for understanding the mechanism of strong adhesion.
Crack Initiation of Type 316L Stainless Steel Under Cyclic Deformation in Simulated Body Fluid
Authors: Doi Kotaro , Miyabe Sayaka , Tsuchiya Hiroaki , Fujimoto Shinji 
Published: February 2020

The inside of body is a complex environment for metallic biomaterials because of the synergetic effects of biological factors such as a body fluid including Cl-, proteins and cells, and mechanical factors such as strain, bending and friction. These complex factors may lead the corrosion fatigue which is the commonly experienced degradation of metallic biomaterials. However, crack initiation on type 316L stainless steel with cyclic loading in a simulated body fluid including proteins and cells has been little examined. In the present study, a cyclic stress was applied to the tensile specimen of type 316L stainless steel in the simulated body fluid with cell culturing in order to investigate the crack initiation on the metallic biomaterials in the body environment.
A sheet of type 316L stainless steel was shaped into samples for tensile test with a gauge size of 8×4×1 mm3. The samples were mirror-finished, then immersed in a-MEM (Minimum Essential Medium) for 1 day which is a simulated body fluid commonly used for cell culturing (Immersed sample), or immersed in a-MEM+10 vol.% FBS (Fetal Bovine Serum) with cell culturing for 1 week (Sample with cells). During immersion, a-MEM and a-MEM+10 vol.% FBS were kept at 37 °C under an atmosphere of 5 % CO2-20% O2-75 % N2. Initially, Immersed sample and sample with cells were placed in the electrochemical cell filled with a-MEM kept at same condition in immersion, then attached to a corrosion fatigue test machine. A cyclic stress was applied to the sample until 107 cycles. The stress ratio was 0.1 (R=0.1) and the maximum stress was 300 MPa, not exceeding the elastic limit of type 316L stainless steel. The stress frequency was 10 Hz. For comparison, the sample not immersed was also subjected to the test in the air (Sample in the air). After cyclic deformation, cracks initiated on the sample surface were observed using FE-SEM. In addition, crystalline structure of the sample was analyzed using EBSD (Electron Backscatter Diffraction Analysis). From surface observation and EBSD, the relationship of crack initiation and crystalline structure was studied.
Most cracks observed on the sample in the air, immersed sample and sample with cells initiated in the grains with Schmidt factor being from 0.4 to 0.5. This result indicates that the cracks tend to initiate along crystal plane with the largest Schmid factor where slip deformation preferentially occurs. On the other hand, non-negligible amount of cracks were observed on the crystal plane with Schmid factor less than 0.4 for the immersed sample and sample with cells. Such cracks initiated along the slip direction toward inside of the sample. In this case, the newly created surface was exposed to a solution, then corrosion along the slip steps was enhanced. Therefore, in the immersed sample and sample with cells, crack initiation was prompted on the crystal plane with the non-largest Schmid factor.
Nitridation of a Fecral Alloy in H2+N2 Environment at 900oc: A Microstructural Study
Authors: Mortazavi Nooshin , Geers Christine , Jönsson Bo , Svensson Jan-Erik , Sundell Gustav , Johansson Lars-Gunnar , Halvarsson Mats 
Published: February 2020

When exposed to O2 and/or H2O at high temperature, iron-chromium-aluminum (FeCrAl) alloys form an adherent a-Al2O3 scale that grows very slowly. Because of the excellent protective properties of this scale, the FeCrAls resist high temperature corrosion and oxidation very well and they are used in a wide range of high temperature applications up to 1300oC. However, when exposed to nitrogen-containing environments with low oxygen activity, e.g. H2+N2 mixtures, the FeCrAls become sensitive to nitridation. Such environments are often used in heat treating and sintering operations. This paper investigates the nitridation behavior of the FeCrAl alloy Kanthal APMT at 900°C. In order to provoke nitridation, the material was exposed to a N2+H2 mixture with very low water vapour content. Microstructural analyses after 24h exposure revealed that a continuous Al2O3 scale covered almost all of the alloy surface. However, the oxide scale contained a distribution of Cr2O3 patches with diameters of 10-40 mm. Cross-sectional studies using Focused Ion Beam (FIB) milling showed internal nitridation of the alloy, displaying a variety of precipitates below the Cr2O3 patches, including needle shaped AlN, equiaxed Cr2N and CrN particles. In contrast, the alloy beneath the Al2O3 scale was not nitrided. To investigate possible reasons for the formation of chromia patches we kept track of specific regions before and after exposure. Hence, several analytical techniques were employed to fully characterize the alloy microstructure prior to the exposures, using Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Energy Dispersive X-ray (EDX) analysis. Some markers were used to enable identification of specific areas during post-exposure analysis and to enable correlation of chromia formation and internal nitridation with the alloy microstructure.