bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Digital Presentation) Cathodic Exfoliation of Few-Layer Tellurium As Electrocatalyst Support for Hydrogen Evolution
Authors: Zheng Weiran , Lee Lawrence Yoon Suk 
Published: November 2022

Few-layer tellurium represents the two-dimensional (2D) form of tellurium crystal with the majority of the Te atoms exposed on its surface. Recent studies demonstrated that 2D Te has good environmental stability and high charge carrier mobility, making it suitable electrocatalyst support to host active sites and assist electron transfer between the electrode and the sites [1]. Yet, its mass production for electrocatalysis application remains challenging.
In this study, we present a simple cathodic exfoliation method to exfoliate commercially available Te crystal directly into few-layer tellurium with exceptionally high yield [2] (see Figure 1A). Using alkaline aqueous electrolyte (1.0 M KOH), Te nanosheets with the thickness of 7~10 nm and lateral size of 1~4 µm were produced at an applied potential of −0.42 V (vs. RHE). Combining in situ Raman spectroscopy and ex situcharacterization results, we were able to reveal the exfoliation mechanism, where the in situ generated ditelluride (Te2
2−) anions on the nanosheets played the critical role of separating nanosheets from the bulk crystal (see Figure 1B).
At the presence of transition metal ions in the electrolyte, such as Pt2+ and Ni2+, simultaneous surface doping of Te nanosheets was enabled by the interaction between Te2
2− anions and metal ions, producing Pt/Ni-doped Te with tunable doping level. Such doped nanosheets exhibited high stability and hydrogen evolution reaction (HER) activity. Particularly at high potential, Pt-doped Te nanosheets outperformed both polycrystalline Pt and commercial Pt/C catalysts (see Figure 1C). We suggested a collaborative hydrogen production mechanism via Volmer–Heyrovsky pathway to justify such unusual activity. In short, at HER conditions, the surface Te atoms of Pt-doped Te nanosheets are reduced to Te2
2− anions. Such species can help attract protons and assist their transfer to adjacent Pt atoms, where the protons are reduced to form hydrogen (see Figure 1D).

Figure 1 (A) Experimental setup and photos of the electrochemical exfoliation of Te crystal; (B) Exfoliation mechanism; (C) HER performance and relative energy of Pt-doped Te with various doping levels; (D) Collaborative HER mechanism.

Reference:

Shi, Z.; Cao, R.; Khan, K.; Tareen, A. K.; Liu, X.; Liang, W.; Zhang, Y.; Ma, C.; Guo, Z.; Luo, X.; Zhang, H., Nano-Micro Lett.
2020, 12 (1), 99.

Zheng, W.; Li, Y.; Liu, M.; Lee, L. Y. S., Small
2021, 17 (18), e2007768.

Figure 1
(Digital Presentation) Charge Trapping in TiO2 Nanoparticles
Authors: Juhasz Gergely 
Published: November 2022

TiO2 is a common component of electrode surfaces and photocatalytic systems. Depending on the preparation, the oxide can be formed in different shapes and morphology which can effect the selectivity and efficiency of the electrode [1]. Since the morphology and shape of the nanoparticles can be easily tuned with experimental conditions, this may offer a new, unexplored strategy to improve electrode properties in these systems. The goal of our computational studies is to understand better how charge carriers behave in these oxide nanoparticles.
We studied the electronic states around the bandgap in anatase-type TiO2 nanoparticles of different shapes with (101) and (001) facets using Density Functional based Tight Binding (DFTB) and DFT methods. The previous calculation has already shown that most orbitals of the valence and conduction bands form delocalized band-like orbitals; however, there are a significant number of localized states at the lower edge of the conduction band, too. The calculations clearly show the position of these trapping sites when we compare the electron density of neutral and charged nanoparticles.

Reference:

[1] Selectivity enhancement in the electrochemical reduction of oxalic acid over titanium dioxide nanoparticles achieved by shape and energy-state control. H Eguchi, K Kato, G Juhasz, M Yamauchi - Catalysis Science & Technology, 2021
Figure 1. The electron density difference between negatively charged and neutral nanoparticle (left); electron density difference reflected in Mulliken charges of the atoms (right).

Figure 1
Electrochemical Behavior of MgOH+ in Molten MgCl2-KCl-NaCl Salt
Authors: Witteman Liam , Rippy Kerry , Vidal Judith , Taylor Patrick R. 
Published: November 2022

Research on molten chloride salts as a high-temperature (500-800 ℃) heat transfer fluid has been reinvigorated in recent years. Its abundance, low cost, and good thermohydraulic properties have drawn attention from the nuclear and concentrated solar power industry. Specifically, a ternary MgKNa chloride salt (45.98/38.91/15.11 wt.%) has been considered a prime candidate for commercial application. However, economic risk remains due to high corrosion of containment alloys.
The rate of corrosion in ternary MgKNa chloride salt has been primarily attributed to the impurity MgOH+, stemming from the reaction of MgCl2 with moisture. Extensive research has been conducted to purify chloride salts, but little attention has been given to on-line purification strategies once the salt is molten and circulating in the plant. One proposed strategy is continuous electrochemical purification via electrolysis using a Mg anode and W cathode. This strategy has been successfully demonstrated at the laboratory scale. Work done in our group indicate significant opportunity for the electrochemical process to be scaled up commercially as an electrochemical purification unit.
Here, we present a study on the electrochemical behavior of MgOH+ reduction on a W cathode in molten MgCl2-KCl-NaCl across the temperature range of 475-525 ℃. The kinetic parameters from this study aid in modeling and scaling up an electrochemical purification cell at industrially relevant scales.
Anodic Behaviour of Ni-Fe-Cu electrode In Molten Fluoride Salts
Authors: Saevarsdottir Gudrun , Singh Kamaljeet , Haarberg Geir Martin , Bourmaud Milane , Padamata Sai Krishna Krishna 
Published: November 2022

The industrial process for Aluminium production is the Hall-Héroult process, an electrolysis process where the alumina raw material is dissolved in a cryolite based electrolyte, the aluminium is deposited at the cathode while the oxygen from the alumina reacts anodically with the carbon anodes, which are consumed in the process. The chemical energy in the carbon anodes provides part of the process energy, resulting in CO2 emission of about 1.6 kg/kg aluminium produced. In industrial cells, the electrolyte is modified from the cryolite, Na3AlF6, composition by adding AlF3 to lower the process temperature and improve current efficiency. This modification can be characterized by the Cryolite Ratio, CR, which is the molar ratio of NaF/AlF3. In modern cells, this ratio is often as low as 2.2, as compared to 3 in pure cryolite, which enables an operating temperature of around 960°C, as compared to more than 1009°C for Cryolite.
One way to eliminate CO2 process emissions from aluminium electrolysis is to switch from consumable carbon anodes to inert anodes, resulting in O2 emissions instead of CO2. Significant effort has been put into achieving this, but the challenge is to find anode materials that can withstand the harsh conditions in the high temperature cryolite based electrolyte. It would help anode life to reduce the electrolysis temperature from 960 °C to 800 °C or lower. Lowering the CR to 1.3 or lower would achieve this, but for traditional electrolyte components this would lower the alumina solubility to unacceptably low levels. By replacing some of the NaF in the electrolyte with KF, it is possible to operate at this very low CR with acceptable alumina solubility.
In this paper, we present a study on anode performance in potassium-rich low CR electrolyte. Both electrodes are vertical, the anodes made of homogenised CuFeNi alloy and cathodes of hot-pressed TiB2. The paper describes the effect of varying the anode composition, anode surface treatment as well as current density on anode stability. Also, the effect of varying the ratio of KR = KF/(NaF+KF), process temperature as well as alumina saturation is addressed.
In general, pre-oxidation of the metallic anodes as well as the Cu content greatly affects anode stability. It is possible to operate at low temperature at lower KR, improving the industrial viability of the process, as NaO is added to the cells with the alumina, this reduces the alumina solubility which puts constraints on the process control. The aluminium obtained by electrolysis in this system had less than 0.2% impurities from the electrodes.
Determination of the Formation Potential of Solid-Electrolyte Interphase in Some Amide-Type Ionic Liquids Containing Metal Salts
Authors: Kato Shodai , Serizawa Nobuyuki , Katayama Yasushi 
Published: November 2022

Amide-type ionic liquids (ILs) have been investigated as the electrolyte for secondary batteries because they have such favorable properties as non-flammability, low-volatility, and the electrochemical stability.1,2 However, the ILs have been reported to decompose cathodically at the potentials more positive than the deposition potential of Li and form solid-electrolyte interphase (SEI) on the electrode.3 Although the formation of the SEI is favorable for lithium secondary batteries, the SEI may hinder the electrode reactions of the active materials when the ILs are used as the electrolytes for redox flow batteries. In the present study, the formation potentials of the SEI in two amide-type ILs, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)amide (BMPFSA) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing metal salts were investigated in the presence of a redox species.

BMPBr was prepared by the reaction of 1-methylpyrrolidine and 1-bromobutane in acetonitrile. BMPFSA was obtained by the interaction of BMPBr with LiFSA in distilled water. BMPFSA was dried under vacuum at 80 °C for 48 hours before use. BMPTFSA and the metal salts were used as supplied. The water content in BMPFSA and BMPTFSA was less than 10 ppm. The electrochemical measurement was carried out with a three-electrode cell in an argon-filled globe box. A Pt disk and wire were used as a working and counter electrode, respectively. Ag wire immersed in BMPFSA or BMPTFSA containing 0.10 M AgCF3SO3 was used as a reference electrode, which is denoted by Ag|Ag(I).

The anodic peak potentials in the cyclic voltammograms in the ILs containing the redox species were almost constant after holding the potentials more positive than the cathodic decomposition potentials. On the other hand, the anodic peak potentials changed by holding the potential at the negative potential region in the presence of the metal species, suggesting that the potential of the SEI formation can be determined more sensitively by monitoring the redox reaction.
References
[1] M. Yamagata, Y. Katayama, and T. Miura, J. Electrochem. Soc., 153, E5 (2006).
[2] K. Matsumoto, T. Hosokawa, T. Nohira, R. Hagiwara, A. Fukunaga, K. Numata, E. Itani, S. Sakai, K. Nitta, and S. Inazawa, J. Power Sources, 265, 36 (2014).
[3] R. Furuya, N. Tachikawa, K. Yoshii, Y. Katayama, and T. Miura, J. Electrochem. Soc., 162, H634 (2015).
Optimizing the Current Collector for Sodium Iodide-Metal Halide Catholytes in Low-Temperature Molten Sodium Batteries
Authors: Maraschky Adam M. , Meyerson Melissa L , Percival Stephen J. , Gross Martha M. , Peretti Amanda S. , Spoerke Erik D. , Small Leo J. 
Published: November 2022

Low-cost, long-duration energy storage is critically needed for a robust electric grid powered by renewable sources. In the pursuit of meeting this need, low-temperature (<130 °C) molten sodium batteries (MNaBs) with NaI-metal halide molten salt catholytes have been developed. This battery design circumvents many of the safety concerns caused by metal dendrites and flammable organic solvents found in Li-metal or Li-ion batteries. It also drastically reduces the high-temperature material requirements and operating costs compared to traditional MNaBs, such as ZEBRA, which operate near 300 °C. The presented battery operates at 110 °C—just above the melting point of Na (98 °C). It features a molten Na anode, a NaSICON ceramic separator, and a NaI/AlCl3 catholyte.
Among the key challenges to widespread utilization of these emerging MNaBs is reducing the overpotential on the cathode while operating at practical current densities over numerous cycles. To improve the performance of the cathode, we examined the electrochemical behavior of a variety of disk electrode materials, including W, Mo, Ta, and glassy carbon (GC) in a 3-electrode configuration. A custom cell was designed to mimic a full battery with separators for both the reference and counter electrodes. Excess molten salt was used to keep bulk concentrations practically constant over the course of the experiments. This enabled experiments that isolated the working electrode from other battery elements, such as a changing catholyte or the NaSICON interfaces. Voltammetry, electrochemical impedance spectroscopy, chronopotentiometry, and chronoamperometry were used to evaluate each material’s charge/discharge kinetics and stability. Instability on charging is hypothesized to be due to iodine (I2) adsorption on rapid iodide (I-) oxidation. Discharge, on the other hand, is limited by the transport of triiodide (I3
-), which depends on the battery’s state of charge. Insights from these studies serve as the foundation for the rational design of high-surface area electrodes for iodide-based molten salt catholytes. After initial testing in the 3-electrode cell, the performance of several high surface area current collectors was evaluated in rate tests and continuous cycling of lab-scale battery cells.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Electrodeposition of Nickel From an Amide-Type Ionic Liquid Under a Magnetic Field
Authors: Katayama Yasushi , Manabe Yuina , Serizawa Nobuyuki 
Published: November 2022

Aprotic ionic liquids are considered to be used as the promising electrolytes for electrodeposition of wide variety of metals and alloys. Nickel is one of the ferromagnetic metals and can be deposited in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing Ni(TFSA)2.[1] Furthermore, Ni nanoparticles were prepared in the ionic liquid by potentiostatic cathodic reduction at a negative potential region.[2] Recently, we reported that the nanowires of a ferromagnetic metal and alloy could be deposited electrochemically by applying a static magnetic field without any template.[3-5] The formation of metal nanowires is considered to be due to the magnetization and self-organization of the nanoparticles at the electrode-electrolyte interface. Thus, the similar nanowires are expected to be obtained for ferromagnetic metals like Ni. In the present study, electrodeposition of Ni was conducted in BMPTFSA containing Ni(TFSA)2 under a static magnetic field.
The cathodic reduction of Ni(II) was observed in the cyclic voltammogram of a glassy carbon (GC) electrode in BMPTFSA containing Ni(TFSA)2, as reported previously.[1] An increase in the cathodic peak current and the positive shift of the onset potential of the cathodic current were observed when a magnet was attached on the backside of the GC electrode. Granular deposits were observed after potentiostatic cathodic reduction without the magnet. However, nanowires were deposited on the GC electrode with the magnet, verifying the electrodeposition of ferromagnetic metals in the ionic liquid under a magnetic field leads to the formation of the nanowires.
References
[1] Y.-L. Zhu, Y. Katayama, and T. Miura, Electrochim. Acta, 54, 7502 (2009).
[2] Y.-L. Zhu, Y. Katayama, and T. Miura, Electrochem. Solid-State Lett., 14, D110 (2011).
[3] M. Manjum, N. Serizawa, A. Ispas, A. Bund, and Y. Katayama, J. Electrochem. Soc., 167, 042505 (2020).
[4] M. Manjum, N. Serizawa, and Y. Katayama, J. Electrochem. Soc., 168, 042504 (2021).
[5] H.-W. Yeh, N. Serizawa, and Y. Katayama, J. Electrochem. Soc., 168, 082502 (2021).
Probing Local Ion Insertion through Strain-Current Correlation
Authors: Tsai Wan-Yu , Balke Nina 
Published: November 2022

Among different electrochemical energy storage devices, the ones that store a higher amount of energy (e.g., batteries) often undergo larger ion insertion-induced structural transformation and volume change, which results in lower rate performance. The ones that store a lower amount of energy (e.g., supercapacitors) usually show gradual structural change and smaller volume change. There is a strong correlation between electrochemistry and mechanical properties. Understanding the electro-chemo-mechanical coupling and controlling the ion insertion-induced strain is crucial for achieving high power and high energy storage devices. In-situ atomic force microscopy (AFM) is well suited to tackle this task as it allows tracking local volume changes and other mechanical responses sub-nanometer spatial resolution under the conditions close to the device operation
In this work, we monitored electrode volume change via in-situ AFM and demonstrated the electro-chemo-mechanical coupling behaviors during proton insertion into WO3 materials. The concept of mechanical cyclic voltammetry (mCV) curves was developed, and the relationship between electrochemical current and strain was investigated with simplified models. The results revealed multiple ion-intercalation processes with different mechanical responses are involved during electrode cycling. Local heterogeneity was investigated via mCV mapping, confirming that the charging mechanisms varied across the electrode. These local variations could be further correlated to local morphology, crystal orientations, or chemical compositions. We further demonstrate that the mCV approach is applicable to a variety of energy storage materials (e.g., birnessite and MXene) with the increasing complexity of current-deformation relationships.
The work was supported by the Fluid Interface Reactions, Structures, and Transport (FIRST), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Measurements were performed at the Center for Nanophase Materials Sciences (CNMS), which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences.
Developing in Situ Electrochemical Techniques to Understand Mechanisms of Bubble Formation at Aqueous Electrochemical Interfaces
Authors: Zhu Qianhong , Tarpeh William Abraham 
Published: November 2022

Many electrochemical water treatment techniques (e.g. nitrate reduction, reactive oxygen species production, direct contaminant oxidation/reduction) rely on the electrochemical reactions that occur at the solid-liquid-gas triple-phase boundary layer, where gas species could be reactants, products, or undesired by-products. Developing foundational knowledge of the mechanisms by which surface bubbles form and how they impact chemical reactivity at surfaces would enhance the optimization and sustainability of electrified water treatment processes.
The overall research goal is to develop in situ scanning electrochemical microscopy (SECM) to improve the microscopic understanding of how gas bubbles nucleate, form, grow, and migrate at solid–liquid interfaces. An important subset of gas-involving or gas-evolving, interfacial electrochemical reactions produces gas molecules dissolved in solution that can nucleate as small nanobubbles on electrode surfaces. These bubbles can grow to macroscopic sizes and interfere with chemical processes by blocking reactants from reaching the electrode-electrolyte interface, or by increasing turbulent mixing via leaving the surface. SECM is used to map the bubble formation mechanisms on the interface and to quantify the chemical species (reactant and product) concentration profile within the diffusion layer of the electrode surface. Here we will use oxygen reduction reaction (ORR) to hydrogen peroxide and nitrate reduction reaction (NO3RR) to ammonium as two model systems to investigate how SECM could help us understand chemical reaction mechanisms at aqueous electrochemical interfaces.
A Comparative Study on Gold Dissolution in Broad pH Range from Acidic to Alkaline Media
Authors: Stojanovski Kevin , Briega Martos Valentin , Zlatar Matej , Cherevko Serhiy 
Published: November 2022

Gold is often employed in nanotechnology to develop biosensors and new drug delivery and cancer therapy strategies. Since these applications are used in physiological pH, understanding the stability of gold in a broader pH range including neutral values will provide an useful insight into how to expand the use of gold safely.
By using buffer solutions with a constant concentration of phosphate species, electrochemical dissolution of gold in pH 1, 3, 5, 7, 9, 11 and 12.7 was investigated. The concentration of phosphate species was kept constant in order to minimize the possible effect of anion concentration on gold dissolution. Oxidation/reduction of the metal surface leads to transient dissolution peaks, which are labelled as A1 and C1 on the dissolution profiles on Figure 1. An additional dissolution peak A2 appears when the oxygen evolution reaction (OER) takes place. Quantitatively, there are significant differences. The amount of gold that is transiently dissolved in an alkaline medium is more than an order of magnitude higher than that in an acidic medium at lower potentials. Oppositely, steady-state gold dissolution in alkaline pH in the potential region of OER is hindered. There is an apparent shift in the mechanisms at pH 5. At higher potentials, i.e 1.9 V RHE, there is an apparent loss of peak A2 and a growth of C1. The loss of dissolution of gold due to a change in the mechanism of OER in more alkaline electrolytes is clear at pH 7. To explain the observed difference in gold dissolution, a difference in the thickness of compact oxide formed in acid and base is suggested. The formation of thicker oxide as a result of an increase in pH becomes noticeable with the observed increase in both peaks A1 and C1 that can be seen when the pH is increased from 7 to 12.7. These new data on Au dissolution in a broad potential and pH range should be used to minimize Au dissolution in various applications.

Figure 1