bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) High-Active, Long-Term Stability of Low-Platinum Fuel Cell Electrocatalysts: From in Situ Understanding to Rational Design
Authors: WU Jianbo 
Published: May 2020

The Pt based atomic layered core-shell catalysts has been proven to be one of the most promising oxygen reduction (ORR) electrocatalysts with high activity and low usage of Pt.1-5 It is important to directly observe the growing dynamic of Pt atomic layers. On the other hand, corrosion is a major and unavoidable challenge for the degradation of multimetallic core-shell electrocatalysts, which restricts the practical application of this electrocatalysts severely.6-7 Therefore, it is urgent to understand the evolution and mechanism of corrosion of Pt-based core-shell catalysts during the reaction with an aim to the effective utilization of the Pt catalysts. 8

In this presentation, we will report a direct obversation of the formation of core-shell nanostructures involving a hybrid competition with island growth and surface diffusion. Based on this in situ insight, we further demonstrate that the desired atomic layered surface structure can be achieved by adjusting the competition between island deposition and surface diffusion.9 Then, we will show the corrosion behavior of Pd@Pt core-shell electrocatalysts in the etching solution, and indicates that the corrosion behaviors depends on the effects of geometry, surface defect and built-in strain.10-11 Finally, we demonstrate the capability of electrochemistry inside of TEM, showing both the oxidative etching and the re-deposition behaviors during the cyclic oxidation and reduction in CV within TEM.
References:
1. Wu, J.; Yang, H., Platinum-based oxygen reduction electrocatalysts. Acc. Chem. Res.
2013, 46, 1848-1857.
2. Bian, J.; Zhang, H.; Jiang, Y. Y.; Jin, C. H.; Wu, J. B.; Yang, H.; Yang, D. R., Nano Lett. 2015, 15, 7808-7815.
3. Yan, Y. C.; Shan, H.; Li, G.; Xiao, F.; Jiang, Y. Y.; Yan, Y. Y.; Jin, C. H.; Zhang, H.; Wu, J. B.; Yang, D. R., Nano Lett. 2016, 16, 7999-8004.
4. Xiong, Y. L.; Shan, H.; Zhou, Z. N.; Yan, Y. C.; Liu, Y. F.; Tian, H.; Wu, J. B.; Zhang, H.; Yang, D. R., Small, 2017, 13, 1603423.
5. Wang, X.; Choi, S.; Roling, L.; Luo, M.; Ma, C.; Zhang, L.; Chi, M.; Liu, J.; Xie, Z.; Herron, J.; Mavrikakis, M.; Xia, Y. Nat. Commun. 2015, 6, 7594.
6. Lim, B.; Jiang, M.; Camargo, P. H.; Cho, E. C.; Tao, J.; Lu, X.; Zhu, Y.; Xia, Y., Science
2009, 324, 1302-1305.
7. Zhang, L.; Roling, L. T.; Wang, X.; Vara, M.; Chi, M.; Liu, J.; Choi, S.-I.; Park, J.; Herron, J. A.; Xie, Y., Science
2015, 349, 412-416.
8. Wu, J.; Shao, H.; Chen, W; Gu, X.; Tao, P.; Song, C.; Shang, W.; Deng, T, Adv. Mater., 2016, 28, 9686-9712.
9. Wu, J.; Gao, W.; Wen, J.; Miller, D. J.; Lu, P.; Zuo, J. M.; Yang, H., Nano Lett., 2015, 15, 2711–2715.
10. Wu, J.; Gao, W.; Yang, H.; Zuo, J. M., ACS Nano, 2017, 11, 1696-1703.
11. Shan, H.; Gao, W.; Xiong, Y.; Shi, F.; Yan, Y.; Ma, Y.; Shang, W.; Tao, P.; Song, C.; Deng, T.; Zhang, H.; Yang, D. R.; Pan, X. P.; Wu, J., Nat. Commun., 2018, 9, 1011
Effect of Ligand-Complex Interactions on the Electrodeposition of Mixed Chromium Metal-Carbide-Oxides from Trivalent Chromium Electrolytes
Authors: Ankora Maxine V. E. , Wijenberg Jacques H.O. J. , Terryn Herman , Mol Johannes M. C. 
Published: May 2020

Electrolytic chromium coated steel (ECCS) is packaging steel coated with a thin layer of chromium with an outer layer of chromium oxide. This coating system provides corrosion protection in addition to good adhesion properties due the outer oxide layer. The coating for ECCS is deposited via a hexavalent chromium electrolyte which has been found to be an environmental and health hazard and is therefore subject to restrictions under REACH legislation. A new coating process based on trivalent chromium chemistry has therefore been developed.
According to prior studies, coatings comparable in terms of corrosion resistance to those achieved with the traditional Cr(VI)-based process have been produced with this process [1]–[4]. However, at present there is limited understanding of the mechanism and kinetics of electrodeposition from trivalent chromium based electrolytes. This knowledge is key to optimize the process design for industrial plating lines.
In the present study, we investigate the effect of the chemistry of the Cr(III) complex – as determined by the relative concentration of the formate complexing agent and temperature – on the electrodeposition of mixed chromium metal-carbide-oxide coatings on low carbon steel in a rotating cylinder electrode (RCE) setup.
In this study, low carbon steel samples are electroplated in an aqueous Cr(III) based electrolyte bath with a deposition time of 0.8 s with applied current densities ranging from 20 to 90 A dm-2. The pH of the electrolyte is maintained at 2.6. A rotation speed of 776 RPM is used. SEM and XPS analysis is also performed to determine the effect of the above parameters on the microstructure and composition of the deposits. The amount of Cr deposited is determined using XRF measurements. Relative chromium metal, oxide and carbide contents are determined via XPS analysis. UV-Vis spectra of each of the electrolytes are also measured.
Optical surface analysis shows that of the three regimes distinguishable as a function of current density [2], homogeneous, bright coatings are deposited in regime II (Figure 1). The current range over which acceptable coatings are deposited is significantly wider with higher relative ligand concentrations. Lower applied currents are required with lower bath temperatures. Increasing the chromium ion concentration (at a fixed relative ligand concentration) results in increased Cr metal deposition and an associated decrease in the carbide content of the coating. At higher bath temperatures, carbide formation is favoured. Results also indicate a threshold ligand-to-complex ratio at ~2.0 [HCOO-]/[Cr3+] above which a bright, homogeneous coating is deposited. This threshold corresponds with UV/Vis results which indicate the formation of a new complex species in the electrolyte at that ratio (Figure 2).

Figure 1
Impacts of Solute and Solvent Coordination on Concentrated-Electrolyte Transport
Authors: Wang Andrew , Fawdon Jack , Hou Tianhong , Pasta Mauro , Monroe Charles W. 
Published: May 2020

Super-concentration of electrolytic solutions has been hypothesized as a route to improve battery performance [1]. To predict electrolyte behavior accurately in superconcentrated systems, one must account for their fundamentally different molecular structures. Interactions between species such as ion pairs in concentrated electrolytes may impact the transport laws governing diffusion, migration, and convection, and solute-volume effects may be large because the solution volume fraction occupied by salt is extremely high.
Transport phenomena related to solute and solvent structure, such as Faradaic convection and the excluded-volume effect, can have appreciable impact or even dominate in the superconcentrated regime [2]. In very concentrated electrolytes, convection can be important because when dissolved salt occupies a large volume fraction of the liquid, salt flux across the boundary of a solution drives a bulk solution velocity through overall mass continuity. Experiments demonstrate that at high concentration, viscosity no longer determines ion mobility, i.e., the Stokes–Einstein relation fails. The dynamics of ion-pair formation and salt association/dissociation kinetics both can impact the availability of charge-carrying species in an electrolyte. Experimentally, Faradaic convection can be quantified by combining densitometry with electrochemical measurements. Ion speciation and extent of dissociation can be quantified with spectroscopic techniques.
Newman’s application of Onsager–Stefan–Maxwell theory to electrochemical transport considers solute/solute interactions neglected in Nernst–Planck dilute solution theory [3]. We will add to this perspective by discussing how solute-volume effects and ion-association equilibria additionally influence apparent flux-explicit transport properties such as conductivity, diffusivity and transference number [4].
[1] Yamada, Y., Wang, J., Ko, S., Watanabe, E. & Yamada, A. Advances and issues in developing salt-concentrated battery electrolytes. Nat. Energy
4, 269–280 (2019).
[2] Liu, J. & Monroe, C. W. Solute-volume effects in electrolyte transport. Electrochim. Acta
135, 447–460 (2014).
[3] Monroe, C. W. & Delacourt, C. Continuum transport laws for locally non-neutral concentrated electrolytes. Electrochim. Acta
114, 649–657 (2013).
[4] Hou, T. & Monroe, C. W. Composition-dependent thermodynamic and mass-transport characterization of lithium hexafluorophosphate in propylene carbonate. Electrochim. Acta 135085 (2019).

Figure 1
Evolution of Molten Salt Electrolysis in Titanium Production Process
Authors: Yamaguchi Makoto 
Published: May 2020

The Titanium industry uses the Kroll process where titanium sponge is produced from the reduction of titanium tetrachloride by magnesium metal. The byproduct of this redox reaction is anhydrous molten magnesium chloride which must be reduced back to magnesium metal to complete the cycle.
Since the early sixties Osaka Titanium technologies Co., Ltd has developed monopolar and multipolar magnesium electrolysis cells which have been used in the Kroll process.
Monopolar cell has graphite anode and ferrous cathode, whereas multipolar cell has plural graphite bipolar electrodes between graphite anode and ferrous cathode. A magnesium nucleation and growth phenomenon on the graphite bipolar electrodes is different from that on ferrous cathode. Magnesium particles produced on the graphite bipolar electrodes are very fine, which leads to easy back reaction and difficult collection of them. OTC solved this problem and achieved high productivity, energy saving by halves and plant environmental upgrading.
New Insight into Electrochemical Nucleation and Growth of Metal Nanoparticles through Multiscale Approach
Authors: Mamme Mesfin Haile , Łukaczyńska-Anderson Monika , Mernissi Cherigui El Amine , Hubin Annick , De Proft Frank , Ustarroz Jon 
Published: May 2020

Nowadays, supporting metal nanoparticles have attracted much interest due to their fascinating physio-chemical properties and potential application in fuel cells, sensors, catalysis, solar to fuel devices and among others. One of the interesting issues from engaging physiochemical properties of supporting nanoparticles is to understand their nucleation and growth mechanism in order to get a good control of their structural and morphological parameters. Although studied for decades, however, the full details are still out of reach [1]. In this presentation, we will first review the classical theory of nucleation and growth and secondly present our recent finding and theoretical development on the growth of an isolated metal nanoparticle using a combined experimental (linear sweep voltammetry, chronoamperommetry and FESEM) and multiscale modelling approach [2-5]. In this presentation we focused on the modelling approach. The use of such a multiscale framework allows studying nanoscale electrochemical deposition as a whole, without the need to assume a dominant growth mechanism such as diffusion or kinetic control [2-5]. The simulation results reveal that the existing theory of nucleation and growth is only valid for some specific conditions. Some of the findings will be discussed in this presentation.

References

[1]. Ustarroz, J., Hammons, J. A., Altantzis, T., Hubin, A., Bals, S., & Terryn, H. (2013). A generalized electrochemical aggregative growth mechanism. Journal of the American Chemical Society, 135(31), 11550-11561.
[2]. Mamme, M. H., Dolgikh, O., Ustarroz, J., Simillion, H., Terryn, H., & Deconinck, J. (2016). A finite element simulation of the electrochemical growth of a single hemispherical silver nucleus. Electrochimica Acta, 197, 307-317.
[3]. Mamme, M. H., Deconinck, J., & Ustarroz, J. (2017). Transition between kinetic and diffusion control during the initial stages of electrochemical growth using numerical modelling. Electrochimica Acta, 258, 662-668.
[4]. Mamme, M. H., Köhn, C., Deconinck, J., & Ustarroz, J. (2018). Numerical insights into the early stages of nanoscale electrodeposition: nanocluster surface diffusion and aggregative growth. Nanoscale, 10(15), 7194-7209.
[5]. Cherigui, E. A. M., Sentosun, K., Mamme, M. H., Lukaczynska, M., Terryn, H., Bals, S., & Ustarroz, J. (2018). On the control and effect of water content during the electrodeposition of Ni nanostructures from deep eutectic solvents. The Journal of Physical Chemistry C, 122(40), 23129-23142.
In-Situ Raman and DFT Analyses of ZnO Formation Reaction at Zn Negative Electrodes during Discharge Processes
Authors: Kunimoto Masahiro , Yanagisawa Masahiro , Homma Takayuki 
Published: May 2020

Zn is of interest as a promising material for a negative electrode to be implemented in next generation rechargeable batteries. However its morphological changes, such as mossy-like structural growth or dendritic growth, which bring about serious degradation of the battery, are still a major issue. Such changes of the electrode surface are accompanied with the discharge reaction, which is expressed as Zn + 2OH- → ZnO + H2O + 2e-. This indicates that molecular level mechanisms of ZnO formation reaction are necessary to be investigated, to solve the issue of the undesirable electrode surface changes. We have recently shown the growth behavior of ZnO deposits by using in-situ Raman spectroscopy1. This paper describes the ZnO formation behavior during the discharge process in detail, based on the results of the Raman spectroscopy with DFT.
In-situ Raman spectroscopy was performed during the chronoamperometry for the ZnO formation. Our measurement cell is made up of a three electrodes system, in which all the electrodes is Zn. As the system approached the passivation, a strong peak around 400 cm-1 appeared, which represents the ZnO crystal structure formation. This suggests ZnO leads to the passivation of electrode surface. Furthermore, it turned out that the peak of ZnO crystal structure is not so stable: the peak could show blinks within several tens of seconds. This indicates that ZnO formation should go through atomic level structural changes with high flexibility after the deposition. The DFT calculation explains this from the molecular level viewpoint. It suggests Zn electrode significantly decreases the surface diffusion barrier of chemical species. The trend seen here is also shown in our other DFT results, in which Zn surface structure itself is also variable. The character of Zn, which allows flexible structural changes, might govern the growth behavior on Zn electrode surface.
This research was partially supported by the “Development of Systems and Technology for Advanced Measurement and Analysis”, and the “Research & Development Initiative for Scientific Innovation of New Generation Batteries (RISING 2)” from the New Energy and Industrial Technology Development Organization (NEDO) of Japan.
1. T. Otani, T. Yasuda, M. Kunimoto, M. Yanagisawa, Y. Fukunaka and T. Homma, Electrochim. Acta, 395, 90 (2019).
Thermodynamics and Electrochemistry of Thermally Regenerative Ammonia Batteries
Authors: Hall Derek M. , Cross Nicholas R , Lvov Serguei N. , Logan Bruce E. , Rau Matthew J 
Published: May 2020

Deep cuts to global carbon emissions are only possible with a dramatic increase in energy storage capacity. However, the cost of the storage options available hinders the timely deployment of the necessary energy storage. Promising supplements to conventional storage are thermally regenerative ammonia batteries (TRABs), which have an additional advantage of being able to capture low-grade waste heat into dispatchable electricity for the grid. This new battery technology can potentially provide power on demand using low-cost chemistries and waste energy sources relative to their purely electric battery counterparts.
Most of the research to date for TRABs has been proof-of-concept in nature. As such, little is known about how the electrolytes used in these devices impact their theoretical energy storage capacity. Here we present the general principles of TRABs from an electrochemical and aqueous chemistry perspective. Energy storage density values and Eh-pH diagrams are presented to highlight key factors that govern these complex but versatile energy storage devices. Ag-based and Cu-based TRABs are discussed, and some experimental data confirming the conclusions of the Eh-pH diagrams are presented.
Cobalt/Chromium Carbide Composite Coatings Applied By Brush Plating for Use As an Alternative to Hard Chrome
Authors: Thomas Joshua David , Milosevic-Popovich Danijela 
Published: May 2020

Due to increased concern for both environmental and worker safety from governments around the world, numerous significant industrial chemicals are being phased out of production processes. One example is the use of hexavalent chromium compounds for the electrodeposition of hard chrome. Electrodeposited chrome is typically used for improved hardness, lubricity, wear resistance, and corrosion resistance. This work will support the use of a metal matrix composite composed of cobalt and chromium carbide particles as an alternative for chrome coatings deposited from hexavalent chromium compounds.
Metal matrix composite (MMC) coatings consist of two phases co-deposited during plating: a continuous metal phase such as cobalt and small (<100 µm) particles of another chemical species distributed throughout. The physical qualities of the composite (such as hardness) are strongly dependent on the ratio and distribution of the two constituent phases. The composition of the plating solution and the parameters used during plating both play important roles in the composition and quality of the final deposit.
While most research has focused on applying metal matrix composites by tank electroplating methods, this presentation will focus on applying the coating via brush plating. Brush plating is a portable electrodeposition technique where solution is applied to the part by a plating solution saturated sleeve on the anode when contact is made to a localized area. Brush plating operations typically use less masking when plating small areas of a larger part. Less solution is needed because the part does not need to be immersed. And the brushing action allows for faster solution replenishment at the electrode surface.
During this presentation, attendees will be shown examples of a matrix material of cobalt co-deposited with either 1 µm or 6 µm chromium carbide particles. Attendees will learn how the concentration of the particle in solution determines the range of particle incorporation; as well as understand how tailoring the plating parameters to the system of particle and matrix is vital to creating a deposit for their specific characteristics.

References:

F. C. Walsh and C. Ponce De León, T. I. Met. Finish., 92, 83-98 (2014)
H. Xiao and S. Clouser, Plating Surf. Finish., 97, 44-51 (2010)
L. I. Arrom, thesis, Cranfield University, Cranfield, UK (2017)
Electrochemical Copper Deposition on Nanoscale-Sculptured Aluminum for Mechanically Stable Joints with Optimal Electrical and Heat Transport Properties
Authors: Schmidt Catarina , Bahr Joerg , Obobi Kalu Chima , Carstensen Jürgen , Adelung Rainer 
Published: May 2020

Copper is a material with a very high conductivity per volume; therefore it is widely used in the industry for nearly every electric application. However, with respect to weight aluminum (due to its low density of 2.7 g/cm3) shows a significantly higher electrical conductivity than copper. For many lightweight applications, aluminum would be the preferred material, but it lacks for good technical solutions for forming easy to apply, corrosion resistant, highly conductive contacts to (other) metals, especially to copper. Many of these problems are related to the native aluminum oxide coating on all aluminum surfaces in contact to air. State of the art solutions for electrical contacting aluminum surfaces require high temperatures and/or high pressure, thus making them expensive and typically damage the surface near microstructure of the aluminum.
In this abstract, we will discuss details of a room temperature technique, which allows for a mechanically stable, corrosion resistant, galvanic copper deposition on aluminum surfaces with extremely high interface conductivity for heat as well as for electrical current. This allows the application of standard bonding technologies for copper (e.g. soldering or using conductive glues) onto aluminum as a conducting material.
The copper deposition technique contains three steps:
1. A special surface preparation, i.e. nanoscale-sculpturing (cf. [1]) which creates a low corrosive aluminum surface structure full of mechanical hooks, composed of 100 crystallographic facets.
2. A preconditioning step before galvanostatic copper deposition.
3. Galvanic copper deposition controlling the nucleation of copper islands within the hooking structure and the morphology of the growing copper layer.
Due to the nanoscale-sculpturing, the deposited copper is mechanically stable bonded to the aluminum surface. Dependent on the demands for subsequent bonding applications, the galvanic copper deposition must be adjusted; e.g. for gluing, large parts of the hook like structure from the underlying aluminum surface should still exist after a thin layer of copper is deposited.
In contrast, for soldering application, a robust and thick layer of copper is needed.
How the nanoscale-sculpturing and the galvanic copper deposition can be adjusted to various application will be discussed in detail.
[1] Baytekin-Gerngross, M., Gerngross, M., Carstensen, J. and Adelung, R. (2016). Making metal surfaces strong, resistant, and multifunctional by nanoscale-sculpturing. Nanoscale Horizons, 1(6), pp.467-472.