bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen Reduction Reaction Activity of Pt-Ni Nanoparticles Prepared By Using Arc Plasma Deposition
Authors: Hara Yuki , Araki Ai , Kato Masaru , Yagi Ichizo 
Published: February 2020

Platinum group metals (PGMs) are used as oxygen reduction reaction (ORR) electrocatalysts at cathodes in polymer electrolyte fuel cells (PEFCs). For mass-production of PEFCs, ORR electrocatalysts with high catalytic activity and low amounts of expensive PGMs should be developed. Alloying Pt with other metals such as Ni reduces Pt amounts used and enhances ORR catalytic activity, caused by the lattice strain and ligand effects [1, 2]. Pt-Ni alloy nanoparticles are usually prepared by wet chemical methods using organic solvents and/or surface modifiers[3, 4]. The use of organic compounds causes contamination of organic impurities, leading to deactivation of Pt-Ni alloy nanoparticles for the ORR. In contrast, dry methods need no organic solvent or surface modifier and will allow us to prepare Pt-Ni alloy nanoparticles with high ORR activity.
Herein, we report Pt-Ni alloy electrocatalysts prepared by using an arc-plasma deposition (APD) method and their electrocatalytic activity for the ORR. The APD is a physical vapor deposition and gives highly dispersible metal nanoparticles under high vacuum [5, 6].In this work, Pt and Ni nanoparticles were co-deposited on a glassy carbon (GC) substrate by using the APD method. Linear sweep voltammograms of Pt-Ni electrocatalysts prepared by the APD showed reduction currents in 0.1 M HClO4under oxygen, indicating that Pt-Ni electrodes are electrochemically active for the ORR (Fig. 1). Pt-Ni electrodes showed higher ORR activity than Pt electrodes prepared by the APD of Pt nanoparticles on GC, suggesting that the synchronized APD of Pt and Ni nanoparticles resulted in the formation of Pt-Ni alloy nanoparticles. The ORR activity of Pt-Ni electrodes that we prepared depended on APD conditions of substrate temperatures and the APD order of Pt and Ni nanoparticles. The ORR activity increased with increasing the substrate temperature (Fig. 1). The APD of Ni nanoparticles followed by the APD of Pt nanoparticles on the GC gave the Pt-Ni electrocatalyst, which showed higher ORR activity than that prepared by the synchronized APD of Pt and Ni nanoparticles.

Acknowledgments

This work was supported by NEDO.

References

1. D, Sung Choi et al., Adv. Mater,28
, 7115–7122 (2016).
2. X. Tian et al., J. Am. Chem. Soc, 138, 1575−1583 (2016).
3. K. Kuttyiel et al., Nano energy, 13, 442-449 (2012).
4. C.Chen et al., Science, 343, 1339-1343 (2014).
5. S. Hoon Kim, et al l., Applied Surface Science
，
297，52–58 (2014)
6. N.Todoroki et al., ACS Catal., 5, 2209-2212 (2015).

Figure 1
Investigating Novel Anion-Conducting Polymers Via X-Ray Scattering
Authors: Schibli Eric Matthew , Wright Andrew G. , Holdcroft Steven , Frisken Barbara J 
Published: February 2020

Hexamethyl-p-terphenyl poly(benzimidazolium) (HMT-PMBI) is a hydroxide-resistant, high-performing anion-conducting polymer. Such materials are very interesting, as they may allow the use of hydrogen fuel cells without platinum-group catalysts [1]. We have investigated the structure of this material using small-angle x-ray scattering (SAXS,) small-angle neutron scattering (SANS,) and computational methods. Our SAXS results revealed three distinct length scales, which we assigned to ion-polymer, interchain, and monomer length scales. A molecular dynamics (MD) simulation reproduced these features of the scattering curve and corroborated our interpretations of them. No structure at larger length scales was observed; the lack of large watery regions, common in high-performance ion-exchange membranes, may contribute to the material’s remarkable mechanical stability.
[1] A.G. Wright and S. Holdcroft, ACS Macro Lett. 3, 444 (2014).

Figure 1
Electrochromic Characteristics of Nano-Sized Cluster Nickel-Oxide Thin Film
Authors: Wang Ke-Hsuan , Kawai Takeshi 
Published: February 2020

Electrochromism is a phenomenon of reversible color change when an external voltage is applied, causing an electrochemical redox reaction. This interesting property leads to the development of several technological applications, such as electronic papers, rear-view mirrors and smart windows. A typical electrochromic device coating is a multi-layer device consisting of an active electrochromic electrode, a counter electrode, an electrolyte layer separating the two electrodes, and two transparent conducting layers serving as electrical leads. A key requirement in developing an electrochromic electrode is to increase the amount of reaction sites of the electrode.
In this work, we report a facile and cost efficient preparation of electrochromic electrode which are formed by assembly of nano-sized clusters of nickel oxides by electrodeposition integrating amino acids. This nanostructured nickel-oxide film with interconnected clusters benefits electrolyte penetration and provide large surface area for charge-transfer reactions. Here, we show that the integration of amino acids resulted in increased nickel-oxide film thickness compared to the system without amino acids. Moreover, the nickel-oxide film also shows a remarkably enhanced electrochromic performance compared to the blank nickel sample. These results demonstrate that the thickness of electrodeposited nickel oxide film thickened with increased reaction site. A three-dimensional (3D) electrochromic material with many reaction sites is achieved. Further, the thickness of electrodeposited nickel oxide film can be tuned by altering kinds of amino acids.

Figure 1
Electrochromic WO3 Films with Controlled High-Rate Deposition By Hollow Cathode Gas Flow Sputtering
Authors: Oka Nobuto , Watanabe Masahiro , Jia Junjun , Sugie Kaoru , Iwabuchi Yoshinori , Kotsubo Hidefumi , Shigesato Yuzo 
Published: February 2020

An amorphous WO3 is one of the most important materials for electrochromic (EC) devices because of its blue coloration caused by electron injection. For the industrial applications including EC smart windows, there are strong demands for EC devices to be produced with a high deposition rate, with a higher stability and at lower costs.
Gas flow sputtering (GFS) has the possibility for very high deposition rate because of using high density hollow cathode discharge and a large amount of sputtering gas (Ar) flow and the stability of the reactive sputtering process in the wide range of the reactive gas (O2) flow, so there is no “transition region” which should appear in the conventional reactive sputtering processes. In this study, reactive GFS was adopted to deposit amorphous WO3 films with the high EC properties with the high deposition rate.
WO3 films were deposited on unheated ITO-coated glass substrate by GFS using two W metal targets which were mounted parallel with each other. Sputtering power was fixed at 1000 W. Ar and O2 flows were 5.0 slm and 10-125 sccm, respectively. Total gas pressures during the depositions were 70 Pa and 90 Pa. X-ray diffraction measurements showed that the all films were amorphous. The density of WO3 films were estimated from data measured by X-ray fluorescence and ICP spectroscopy. The films were electrochemically intercalated with protons and lithium ions. The deposition rates were almost constant with O2 flow during depositions. Figure shows the coloration efficiency of proton intercalated WO3 films as a function of O2 flow during depositions. The coloration efficiency had a tendency to decrease with increasing O2 flow during depositions.
[1] N. Oka, Y. Shigesato, et al., Thin Solid Films 532, 1-6 (2013).

Figure 1
Study about Electrostatic Deposition of CdTe Quantum Dots on Glassy Carbon Electrodes
Authors: Muñoz Eduardo Carlo , Rojas Víctor , Navarrete Emilio Alonso , Román Javier , Henríquez Rodrigo Gonzalo , Schrebler Ricardo Silvio , Romero Mario 
Published: February 2020

Quantum Dots (QDs) are semiconductor nanocrystals. These materials are characterized for its continuous absorption spectra at wavelengths ranging from ultraviolet to visible. This feature is directly related to the size of the nanoparticle. Considering their applications, these materials can be employed in solar cells, lasers, light emitting diodes, electronic devices, among others. However, one of the most attractive applications for QDs has been as sensors or biosensor.
In this work, the synthesis of CdTe Quantum Dots was carried out in aqueous media using Na2TeO3 and CdCl2 as precursors of Te2- and Cd2+ ions, respectively, mercaptosuccinic acid (MSA) as capping agent and NaBH4 as reducing agent. The QDs obtained as colloids were purified and characterized by transmission electron microscopy (TEM), while their optical properties were characterized by UV-visible spectroscopy. After, an electrostatic deposition of the QDs on a Glassy Carbon (GC) electrode was done. This last was carried out applying a positive potential value regarding to the zero charge potential of the electrode in an aqueous media, and the influence of the potential value, deposition time was determined by means cyclic voltammetry. A study of surface conductivity changes of the glassy carbon electrodes after QDs deposition was performed by means Scanning Electrochemical Microscopy (SECM). With this was possible to observe aggregates of CdTe QDs deposited on GC electrodes indicating a possible irreversible electrostatic deposition
Hydrogen Generation Reaction of Sodium Borohydride Catalyzed By Gold and Platinum Nanoparticles
Authors: Long Julia Madeline , Heyman Austin , Huff Clay , Abdel-Fattah Tarek M 
Published: February 2020

The increasing energy demands of the world today have prompted a more thorough investigation into alternative fuels. The renewable nature of hydrogen gas and its environmentally-benign byproducts when produced by the hydrolysis reaction of water and sodium borohydride have identified this as a viable method of production for the alternative fuel. Gold and platinum nanoparticles were synthesized using beta-cyclodextrin for applications in hydrogen evolution reactions from sodium borohydride (NaBH4). The resulting homogenous metal nanoparticles were characterized using Ultraviolet- visible spectroscopy and Transmission Electron Microscope (TEM). Catalytic activity of the hydrogen evolution reactions was measured using a previously described gravimetric water displacement system [1,2]. The data collected shows an increase in the efficiency of the hydrogen generation reaction with the addition of gold and platinum nanoparticles when compared to the un-catalyzed reaction. Overall, gold nanoparticles showed the highest reaction rate of 0.0016 mol-1 sec-1 at a standard concentration of NaBH4, standard pH 7 and an increased temperature at 30 °C. The platinum nanoparticle catalyzed reaction preformed best with a standard concentration of NaBH4 and a standard pH 7 solution producing a rate constant of 0.0021 mol-1 sec-1. All reaction rates were determined to be second order kinematic reactions.

References

1. T. Dushatinski, C. Huff, and T. Abdel-Fattah, Applied Surface Science, 385, 282 (2016).
2. C. Huff, T. Dushatinski, A. Barzanji, N. Abdel-Fattah, K. Barzanji, and T. Abdel-Fattah, ECS J Solid State, 6, M69-M71 (2017).
(Invited) 2D Transition Metal Carbides (MXenes) in Flow-Assisted Electrochemical Energy and Water Technologies
Authors: Akuzum Bilen , Agartan Lutfi , Kumbur E. Caglan , Gogotsi Yury 
Published: February 2020

In recent years, 2D transition metal carbides, also known as MXenes, have attracted much attention and found applications in many different areas due to their unique physical structure and properties [1]. Previous studies have also shown that MXene can exhibit excellent potential for electrochemical energy storage and water treatment applications due to its high electronic conductivity, good chemical and structural stability, and high surface area [1-2]. More recently, our group has found significant potential in utilization of MXene electrodes for flow-assisted electrochemical systems such as capacitive deionization (CDI) and electrochemical flow capacitors (EFCs). For CDI, along with high conductivity and surface area, hydrophilicity of MXenes seems to work well for better pore accessibility. Similarly, easy dispersability in water and high surface charge for solution stability were also found to enable much higher active material loading for flowable electrode systems, which can open up a new plethora of possibilities. In this talk, some of our most recent work on these systems, potentials for further improvement, and some of the potential drawbacks will be discussed.

References

[1] Anasori, B., Lukatskaya, M. R., & Gogotsi, Y. (2017). Nature Reviews Materials, 2, 16098.
[2] Lipatov, A., Alhabeb, M., Lukatskaya, M. R., Boson, A., Gogotsi, Y., & Sinitskii, A. (2016). Advanced Electronic Materials, 2(12), 1600255.
New Anion Exchange Membranes Tailored to Address Problems in Energy Conversion and Water Purification
Authors: Herring Andrew M , Pandey Tara P , Sarode Himanshu N , Liu Ye , Kuo Mei-Chen 
Published: February 2020

Anion exchnge membranes (AEMs) are the weak link in low-cost versatile fuel cells and electrolyzers and in electrochemically driven water purification systems. The potential of anion exchange membrane (AEM) fuel cells to provide inexpensive compact power from a wider variety of fuels than is possible with a proton exchange membrane (PEM) fuel cell, has continued to drive the research interest in this area. Alkaline catalysis in fuel cells has been demonstrated with non-precious metal catalysts, and with a variety of fuels beyond H2 and methanol. Alkaline fuel cells (AFCs), based on aqueous solutions of KOH, have serious drawbacks associated with system complexity and carbonate formation. Anion exchange membrane (AEMs) fuel cells have a number of advantages over both PEM fuel cells and traditional AFCs; however, although anionic conductivity in AEMs can be comparable to PEMs the chemical stability of membrane attached cations in hydroxide is still not always sufficient for practical applications. Recently, it has been recognized that a number of advanced cations, may give AEMs the needed chemical stability for practical applications. Inspired by this we have attached C6 N-heterocyclic cations to a novel tri-block polymer that may be lightly cross-linked. In this way we have fabricated a processable scalable material with a more stable cation that has desirable mechanical properties. We can fabricate these polymers as large area <20 μm films. As an unexpected benefit the material also has low water uptake and high hydroxide conductivity. In this presentation we will discuss the materials properties in terms of its physical chemistry, morphology and ion transport, investigated by PFGSE NMR, SAXS and electrochemical impedance spectroscopy. We will also present some preliminary data on the membranes performance in fuel cells, electrolyzers, and in elecrodialysis for water purification.
Evaluating the Potential for Hydrogen Production with Donnan-Driven Multi-Ion Exchange Membrane Based Systems
Authors: Nazemi Mohammadreza , Agles Avery , Dobson Kelsey , Hatzell Marta C. 
Published: February 2020

Reverse electrodialysis (RED) is a membrane-based electrochemical system used for harvesting salinity gradient energy (2.6 TW) through the mixing of sea and river water at global estuaries[1]. This is accomplished through a series of anion and cation exchange membranes (AEM and CEM), which drive electrical energy production at adjacent redox electrodes. As more membranes are added to the system, the generated potential increases which increases current production.
Galvanic operation of RED for electricity production has been demonstrated, but electrical power density and limiting current density are typically less than 0.2 W/m2 and 10 A/m2 [2]. Here, we propose to produce hydrogen with a RED cell, through operating in an electrolytic mode. This multiple membrane electrolysis process is partially driven by the membranes through their “Donnan-potential”, and partially driven by additional electrical energy input [3-6]. By pushing the RED cell into the electrolytic region, high current density needed for hydrogen production, can be achieved.
Here, hydrogen production using an electrolytic RED is evaluated with a varying number of cell pairs (1 to 10) and with acidic, neutral and basic electrolytes at a fixed 10 mA/cm2. Under neutral conditions, the resulting voltage obtained from the RED cell decreased from 2.1± 0.1 V to 1.2±0.2 as the number of cell pairs increased from 1 to 10. In addition, the energy conversion efficiency of the system decreased due to the increase in mixing energy (ΔGmix.) from 130.6 J to 1203.2 J at higher cell pairs. When the cell was operated with an acidic cathode and basic anode, the applied voltage and energy consumption decreased by 45% compared to neutral pH. In addition, the current density achieved was 4x greater at a voltage 1 cell pair. The hydrogen to electrical energy ratio increased from to 100% at 2 mA/cm2 when the number of cell pairs increased from 1 to 10 with neutral electrolytes. This ratio increased by 3x under acid-base electrolytes.

Logan, B.E. and M. Elimelech. Nature, 2012. 488(7411): p. 313-319.

Zhu, X., He, W., & Logan, B. E. (2015). Reducing pumping energy by using different flow rates of high and low concentration solutions in reverse electrodialysis cells. Journal of Membrane Science, 486, 215-221.

Hatzell, M.C., I. Ivanov, R.D. Cusick, X. Zhu, and B.E. Logan. Physical Chemistry Chemical Physics, 2014. 16(4): p. 1632-1638.

Nazemi, M., Zhang J., Hatzell M.C., “Harvesting Natural Salinity Gradient Energy for Hydrogen Production through Reverse Electrodialysis (RED) Power Generation”, J. Electrochem. En. Conv. Stor., 2017; DOI: 10.1115/1.4035835.

Hatzell, M.C., X. Zhu, and B.E. Logan. ACS Sustainable Chemistry & Engineering, 2014. 2(9): p. 2211-2216.

Nazemi, M., Padgett, J., and Hatzell, M.C. (2017). Acid/Base Multi‐Ion Exchange Membrane‐Based Electrolysis System for Water Splitting. Energy Technology.
Sustainable, Inexpensive Synthesis of High Purity Graphite from Biomass with Excellent Performance in Li-Ion Battery Anodes
Authors: Banek Nathan A , Abele Dustin T , McKenzie Kevin R. , Wagner Michael J 
Published: February 2020

Graphite is classified as a strategic and critical mineral by the US and EU. The worldwide market for graphite was ~ $15 billion in 2016. It is used in numerous industries including metallurgy, refractories and dominates the market for active materials in Li-ion battery anodes.
Both natural and synthetic graphites are used for Li-ion anodes. Natural graphite is mined but requires large-scale beneficiation and purification with HF, HCl and H2SO4, with a large environmental impact to water, land and air. In addition, attaining the purity levels required for Li-ion application results in as much as ~70% material loss. The production of synthetic graphite is a very long and extremely energy intensive process (heating at ~ 3000 ˚C for weeks) and results in very large scale environmentally deleterious emissions.
Predicted growth in the graphite market will be driven by sharp increases in the market for Li-ion batteries, with 12 "mega" factory scheduled to begin production by 2020. Tesla's "giga" factory alone is thought to require the output of 4 - 6 new flake graphite mines or the equivalent quantity of synthetic graphite. However, supplies of natural graphite are under pressure with China recently closing ~ 200 flake graphite mines due to their environmental impact. In addition, shortages in the supply of the high quality needle petcoke necessary for synthetic graphite production are predicted. As a result, graphite price have tripled in the past 10 years, as production has been flat.
Here we report the first Li-ion battery grade synthetic graphite made from biomass. The production is carbon negative, rapid, high yield and low cost. We have demonstrated the synthesis from cellulose, lignin and inexpensive whole biomass feedstock including sawdust and corncob. The resulting graphite is extremely high purity and highly crystalline, matching commercial synthetic graphites. Its performance in Li-ion batteries is outstanding, achieving near theoretical capacity with extremely long cycle life (see figure). Details of the synthesis, characterization and performance will be presented.

Figure 1
Boron-Doped Diamond Sensors for Neurotransmitter Detection: Fabrication and Characterization
Authors: Becker Michael , Rusinek Cory Allen , Fan Bin , Li Wen , Guo Yue , Rechenberg Robert 
Published: February 2020

In vivo neurotransmitter sensing has developed into a significantly prominent field over the course of the past two decades. With biocompatibility and ease of miniaturization, electrochemical methods are a powerful tool for these measurements. This has largely been completed with carbon fiber microelectrodes where several analytes such as dopamine and serotonin have been detected at very low levels. However, carbon fiber electrodes can be prone to fouling and thus, boron-doped diamond (BDD) has emerged as a material capable of long-term reliability and stability. While, BDD-coated tungsten (W) wires have been used for in vivo dopamine detection in mouse brains, a remaining issue is the significant difference in Young’s modulus from BDD (»1000 GPa) and that of brain tissue (103- 105
GPa). The strain between a rigid implant and soft tissue has been thought to be a cause of irreversible tissue damage and negative immune response. Hence, a flexible material is desired to prevent such damage from occurring and polymer-based neural implants have shown promise as a possible implantable device. Though BDD is unable to be deposited directly on a polymer substrate, we developed a wafer transfer process from BDD on silicon (Si) substrates to flexible Parylene-C substrates (an FDA-approved and USP Class VI biocompatible polymer). The fabricated sensors included BDD working, reference and counter electrodes and were characterized using several analytes including Ferricyanide (Fe(CN)6
3/4-), Ruthenium hexaaamine (Ru(NH3)6
2+/3+), and dopamine. Fast scan cyclic voltammetric (FSCV) and chronoamperometric measurements of dopamine were completed as well. These novel fabricated BDD sensors on Parylene-C open a new avenue of electrochemical-based neurotransmitter sensing with potential in vivo measurement capability.

Figure 1