bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulse Electroplating of Zinc/Nickel Alloy from a Deep Eutectic Solvent (DES)
Authors: Ryder Karl Scott , Lei Chunhong 
Published: February 2020

Electrodeposition of metal coatings such as nickel, zinc, tin, chromium and cadmium for the purposes of corrosion protection has been a core interest of the electrochemical community for more than one hundred years. Cadmium has been a favourite for military and aerospace applications because of the combination of good corrosion protection and lubricity. However, cadmium salts are very toxic and hazardous and so the use of cadmium coatings is now proscribed in all but the most demanding of applications. Alternatives to cadmium coatings have included aluminium and more recently zinc nickel alloys. The latter is more accessible via aqueous methods but requires rigorous control and monitoring of bath conditions in order to maintain the composition and quality of the coating.
An alternative to aqueous electrolytes is a derivative of ionic liquids that feature eutectic mixtures of quaternary ammonium salt and hydrogen bond donor. These have become known as deep eutectic solvents (DSE). Here we have used a DES to produce coherent and adherent coatings of zinc nickel alloy in an electrochemical study and in pre-commercialisation scale-up trials.
In a digital controlled pulse-plating method, alternative forward (deposition) and reverse (stripping) currents, are applied to adjust the deposit composition and morphology, as has been demonstrated in film plating from aqueous electrolytes. This report focuses on pulse-plating γ-Zn11Ni2 alloy from a eutectic mixture of choline chloride (ChCl) and ethylene glycol (EG), also known by the commercial name of Ethaline. The effect of pulse shape and frequency on deposit morphology and crystal structure were analysed and compared with coatings derived from constant current (DC) plating methods, through Hull cell tests, XRD, and SEM/EDX measurement. The deposit composition is shown here to be dependent on the average current density, the surface morphology is not sensitive to the pulse frequency, while dendritic growth is shown to be suppressed by pulsed current. We show that the crystal grain size can be controlled according to the pulse shape and frequency. By choosing a certain shape and frequency, the pulse-plating in the DES can provide improved coating qualities and improved process control. Additionally, we have extended the laboratory investigation to pre-commercial scale-up trials with a commercial electroplating company (EC Williams, UK). This project is funded by an Innovate UK action and is entitled Cadmium Replacement Using Pulse-Plating and Ionic Liquids (CRUPPAIL). Barrel-plating trials using pulse and reveres pulse methods on small components such as screws have given even adherent coatings, Figure. The combination of pulse methods and DES electrolyte give a levelling effect, Figure (a), and good throwing power in confined geometries, Figure (b).

Figure: Scanning electron micrographs of Zinc Nickel alloy (85:15%) deposited using DES and pulse-plating on mild steel substrates, (a) sheet, (b) screws.

Figure 1
Design and Optimization of Commercially-Relevant CO2 Electrolyzers
Authors: Weng Lien-Chun , Romiluyi Oyinkansola , Bell Alexis T. , Weber Adam Z. 
Published: February 2020

The electrochemical reduction of CO2 (CO2R) to value-added products is an attractive technology for tackling the rising atmospheric CO2 levels and storing intermittent renewable energy into chemical bonds. Fundamental understanding of CO2R has progressed significantly in recent years and is critical in the development of industrial scale CO2R electrolyzers.1 However, most of our understanding has been drawn from experiments optimized for aqueous-phase CO2R systems. These systems can be limited by mass transfer at fairly low current densities (~10 mA cm-2) due to unfavorable CO2/OH- interactions and large diffusion lengths.2

To achieve commercially-relevant CO2R rates (> 100 mA cm-2), gas-diffusion electrodes (GDEs) play an important role as they can decrease the diffusion length of CO2 to as small as 10 nm.3 The thin diffusion boundary layers in GDEs allow higher CO2R current densities and CO2R to occur under environments with higher OH- concentrations.4 However, with such drastic changes in operating condition and local environment, it is necessary to explore and better understand the transport and reaction overpotential intricacies in GDEs. For instance, conventional cell designs optimized for planar electrodes will suffer from large ohmic drops across the cell due to the higher current density; product distribution will also vary arising from higher CO2 and OH- concentrations near the catalyst.5

In this talk, we present a multiphysics modelling framework to design and optimize GDE systems performing CO2R. We then explore the performance and limitations of various cell designs guided by simulation results and examine potential methods for improving water management and tuning catalyst selectivity. Finally, we discuss the disparities in local environments between aqueous and GDE devices and propose strategies to reduce the gap in knowledge between the two systems.
Acknowledgements
This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. We thank David Larson for providing experimental data for CO2 reduction on membrane-electrode assembly devices.

D. Raciti and C. Wang, ACS Energy Lett., 2018, 3, 1545-1556.

T. Burdyny and W. A. Smith, Energy Environ. Sci., 2019, DOI: 10.1039/c8ee03134g.

L. C. Weng, A. T. Bell and A. Z. Weber, Phys. Chem. Chem. Phys., 2018, 20, 16973-16984.

S. Verma, X. Lu, S. Ma, R. I. Masel and P. J. Kenis, Phys. Chem. Chem. Phys., 2016, 18, 7075-7084.

C. T. Dinh, T. Burdyny, M. G. Kibria, A. Seifitokaldani, C. M. Gabardo, F. P. G. de Arquer, A. Kiani, J. P. Edwards, P. De Luna, O. S. Bushuyev, C. Q. Zou, R. Quintero-Bermudez, Y. J. Pang, D. Sinton and E. H. Sargent, Science, 2018, 360, 783-787.
Tuning the Sensitivity of CO2 Electroreduction on Copper Surfaces Via Electrolyte Engineering
Authors: Akhade Sneha A , Weitzner Stephen Eric , Lucci Felicia , Feaster Jeremy T. , Ivanovskaya Anna N , Wood Brandon C. , Varley Joel Basile , Baker Sarah E , Duoss Eric B 
Published: February 2020

With growing increase in energy demand and chemical production, electrochemical reduction (ER) of CO2 can potentially pave the route for generation of sustainable drop-in fuels using renewable wind and solar energy sources. Cu has been identified as a promising electrocatalyst for CO2 conversion to methane and ethylene, albeit the rates of the electrocatalytic reactions are strongly influenced by the reaction environment and the operating conditions [1,2]. Electrolytic ions are known to impact the rates of electrocatalytic reactions, though a molecular understanding of such impact is not comprehensively understood. Here, we employ a coupled quantum mechanics/molecular mechanics (QM/MM) scheme [3] to investigate the role played by the electrolytic ions under applied potential on the activity-selectivity relationships for CO2 ER. By varying the concentration and identity of electrolytic salts, we investigate their effect on the reaction energetics and binding strength of reaction intermediates in the CO2 ER pathway. Using a high throughput combinatorial approach that spans a wide range of electrolytes, we attempt to create design principles for electrolyte-based tuning of CO2 ER selectivity and compare with experimentally measured CO2 ER selectivities. The results of these studies provide a rationale for improved environment driven design and screening, and allow computation of reaction energetics using nuanced, dynamical models of the electrochemical double layer.*
[1] Y. Hori, in Handbook of Fuel Cells: Fundamentals, Technology and Application (VHC Wiley, Chichester, 2003), Vol. 2, 720-733.
[2] A. Murata & Y. Hori, Product selectivity affected by cationic species in electrochemical reduction of CO2 and CO at a Cu electrode. Bulletin of the Chemical Society of Japan (1991), 64(1), 123-127.
[3] J. Haruyama, T. Ikeshoji and M. Otani, Electrode potential from density functional theory calculations combined with implicit solvation theory. Physical Review Materials (2018), 2(9), p.095801.
*This work was performed under the auspices of the U.S. DOE by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.
Studies of Electrochemical CO2 Reduction in Membrane-Electrode Assemblies
Authors: Romiluyi Oyinkansola , Weng Lien-Chun , Larson David M , Bell Alexis T. , Weber Adam Z. 
Published: February 2020

Gas-diffusion electrodes (GDEs) for electrochemical CO2 reduction allow for an order-of-magnitude increase in obtainable limiting current densities (~100 mA/cm2) compared to planar systems (~10 mA/cm2) due to the increase in CO2 flux, catalyst surface area, and reduction in diffusion length. Despite this improvement, aqueous GDE systems suffer from extensive catalyst dissolution/delamination and membrane degradation under operating conditions, as well as exhibit significant ohmic resistances stemming from their electrolyte layers. These characteristics limit the current densities that can be achieved at applied overpotentials and render them impractical for industrial implementation.
Membrane-electrode assemblies (MEAs), consisting of humidified gaseous feeds at one or both electrodes and no aqueous electrolyte between the electrodes (i.e. only using a solid ion-conducting polymer or ionomer as an electrolyte), can overcome the limitations of the aqueous GDE. In this poster, two MEA cell designs will be addressed: Full-MEA (humidified gaseous feeds at both the anode and cathode) and Exchange-MEA (humidified gaseous feed at the cathode and an adjoining water or salt solution, e.g. KHCO3 or KOH, at the anode to provide hydration and a source of ions). The experimental performance results obtained from the near-optimized vapor-fed Full-MEA and H2O Exchange-MEA systems for CO2RR at ambient temperature and pressure conditions and the details of our ongoing work in building a fully integrated, tandem/cascade catalysis device are described. This poster also details plans for future investigations in exploring critical fabrication, operating conditions, and MEA properties.

Acknowledgements

This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. We would also like to thank Nemanja Danilovic, Kun Jiang, Julie Fornaciari, Yagya Regmi, Douglas Kushner, and Christianna Lininger for their help, discussions, and guidance in the course of this research project.
Towards Efficient Electrocatalytic Conversion of CO2 to Formate Via Novel Electrolyzer Configurations
Authors: Klein Walter Ellis , Chen Yingying , Vise Ashlee , Mooney Mason , Deutsch Todd G , Neyerlin K C 
Published: February 2020

Formate (HCOO-) has been proposed as an intermediate compound to store energy and carbon for microbial conversion to fuels and chemicals1. Formate can be generated by electrochemical reduction of CO2 and subsequently assimilated by microbes that are able to use it as a sole source of energy and carbon for growth and, as recently demonstrated, to produce higher-value chemicals like higher alcohols2. Using formate as an intermediate molecule could provide several advantages over direct conversion from gaseous feeds, such as utilizing renewable energy sources by uncoupling the power availability from the fluctuations inherent to renewable energy sources such as wind, solar, or tidal1. To enable formate as a foundation for the storage of carbon and energy and subsequent conversion to value-added fuels and chemicals, CO2 mass transport limitation issues need to be overcome.
High current densities are required for CO2 electrolyzers to be relevant for industrial applications. Due to the solubility limit of CO2, current densities are restricted to about 30 mA/cm2 in a liquid/planar electrode configuration3. Proof of principle results have shown the mass transport issues can be overcome through utilization of gas diffusion electrodes (GDE) with high interphase (gas/liquid/solid) surface area4.
Here we will discuss how higher current densities and faradaic efficiencies for the gas-phase CO2 to formate conversion process can be achieved through the utilization of novel bipolar membrane (BPM) architectures and reactor designs coupled with optimized reaction condition parameters. We will also show an introductory view of developed testing methods and equipment coupled with in-situ product analysis for electrocatalytic conversions not limited to formate production.
References
[1] Yishai, O., Lindner, S. N., Gonzalez de la Cruz, J., Tenenboim, H. & Bar-Even, A. The formate bio-economy. Curr Opin Chem Biol
35, 1–9 (2016).
[2] Li, H. et al. Integrated electromicrobial conversion of CO2 to higher alcohols. Science
335, 1596–1596 (2012).
[3] Salvatore, D. A. et al. Electrolysis of gaseous CO2 to CO in a flow cell with a bipolar membrane. ACS Energy Lett.
3, 149–154 (2017).
[4] Kopljar, D., Inan, A., Vindayer, P., Wagner, N. & Klemm, E. Electrochemical reduction of CO2 to formate at high current density using gas diffusion electrodes. J Appl Electrochem
44, 1107–1116 (2014).

Figure 1
ZnO/CuO Nanocomposite for Gas Phase Electrochemical Conversion of CO2 to CO at Elevated Pressure
Authors: Malik Karan , Verma Anil 
Published: February 2020

Over the past few years, electrochemical reduction of CO2 (ERC) has attracted a lot of interest among researchers to convert CO2 into value added products using renewable energy.1 Thermodynamic reduction potential of ERC is close to that of hydrogen reduction potential (HER). Moreover, ERC can lead to many products i.e. CO, CH4, C2H4, C2H6, HCOOH, CH3OH etc. depending upon the catalyst and reaction conditions.2 Hence, catalysts play a crucial role in selective electroreduction of CO2. Therefore, majority of the research has been carried out on developing catalyst for selective ERC and most of the studies were conducted in aqueous phase ERC.3 The main limitation of this approach is the CO2 mass transfer limitations due to the low solubility of CO2 in water. However, sufficient studies relevant to the technological development of the direct gas phase ERC are still needed.
In this presentation we will discuss our work on role of pressure in improving gas phase ERC carried out in zero gap cell. We have synthesised ZnO/CuO nanocomposite and ZnO nanoparticles by two methods (wet chemical method and hydrothermal method). We have also synthesised a polyethyleneimine (PEI) based anion exchange membrane. Setup was systematically tested at various operating conditions. Results show that CO2 adsorption on the catalyst aided by the amine functional groups on membrane can be further enhanced by increasing the pressure. As the pressure slightly elevated to 0.5 bar from ambient pressure, HER was supressed and CO faradaic efficiency (FECO) of ~30% was reached. Moreover, current density was increased to ~50mA/cm2 from 4 mA/cm2. In this presentation we will compare the FECO, conversion and current densities of the synthesised electrocatalyst and seek to describe how elevating pressure increases rate of ERC on particular catalyst.
References

D. Raciti and C. Wang, ACS Energy Lett., 3, 1545-1556 (2018).

L.M. Aeshala, R. U. and A. Verma, Phys. Chem. Chem. Phys., 16,17588 (2014).

B. Kim, F. Hillman, M. Ariyoshi, S. Fujikawa and P.J.A. Kenis, J. Power Sources, 312, 192 – 198 (2016).
(Invited) Molecular Dynamics Analysis on the Behavior of Water and Alcohol Liquids on a OH-Terminated SiO2 Surface
Authors: Yamaguchi Yasutaka , Nakaoka Satoshi , Hayashi Takuya , Kawakami Masayuki , Yano Daisaku 
Published: February 2020

Cleaning process to remove impurities is one of the essential processes for the fabrication of semiconductor device, where cleaning of trenches with water, replacement with IPA (isopropyl-alcohol) and its removal are iteratively carried out, and this process is still required upon recent reduction of the line width under 10 nm. This size is already at the border of the continuum limit where the theories of fluid mechanics can be applied. Hence, the authors adopted molecular dynamics (MD) simulations to examine the liquid behavior, especially wetting behavior and solid-liquid friction at the nanoscale with respect to simple Lennard-Jones fluid, water, methanol as well as IPA as the liquids, whereas simple non-polar crystal and silica as the solids [1-8]. In these studies, we have shown that surprisingly the liquid behavior even around this continuum border was qualitatively not remarkably different from that expected from a macroscopic point of view. On the other hand, the physical properties of liquids in the so-called adsorption layers formed in the vicinity of the solid typically of a few molecular diameters, are different from those in bulk, and their effects should be extracted and properly connected to the macroscopic scale, e.g. as a boundary condition to predict the liquid behavior.
In the presentation, we will discuss about the MD simulation results of liquid infiltration into a nanoscale slit, effects of gas molecules in the slit as well the diffusion of water and alcohol molecules on OH-terminated silica surfaces. In addition, the replacement procedure of adsorbed water/alcohol by bulk alcohol/water liquid will be discussed.
[1] Y. Yamaguchi, H. Kusudo, D. Surblys, T. Omori and G. Kikugawa, J. Chem. Phys. 150 (2019), 044701.
[2] D. Surblys, F. Leroy, Y. Yamaguchi, F. Mueller-Plathe, J. Chem. Phys. 148 (2018), 134707.
[3] S. Nakaoka, Y. Yamaguchi, T. Omori, L. Joly, Mechanical Engineering Lett. 3 (2017), 17-00422.
[4] S. Nakaoka, Y. Yamaguchi, T. Omori, L. Joly, J. Chem. Phys. 146 (2017), 174702.
[5] S. Nakaoka, Y. Yamaguchi, T. Omori, M. Kagawa, T. Nakajima, H. Fujimura, Phys. Rev. E 92 (2015), 022402.
[6] S. Nishida, D. Surblys, Y. Yamaguchi , K. Kuroda, M. Kagawa, T. Nakajima and H. Fujimura, J. Chem. Phys. 140 (2014), 074707.
[7] D. Surblys, Y. Yamaguchi , K. Kuroda, T. Nakajima and H. Fujimura, J. Chem. Phys. 140 (2014), 034505.
[8] Y. Yamaguchi, M. Kawakami, D. Yano, Jpn. J. Multiphase Flow 32-2 (2018), 218 (in Japanese).
(Invited) Sputter Beam Epitaxy for Atomic Ordering in Complex Epitaxial Thin Films
Authors: Hauser Adam J 
Published: February 2020

Innovation is driven by the materials mankind has mastered to advance society. Our information age traces back to wartime invention of methods to fabricate silicon and germanium crystals with defects lower than 1 part in 100, a threshold at which the intrinsic properties could then be applied. Today, complex materials (>2 elements with atomic ordering) are at a similar inflection point. Unfortunately, improvement beyond 1 defect in 4 has proven challenging: energetic defects abound and many elements are not compatible with current low-defect growth techniques. Despite significant external funding for the materials themselves, a lack of funding for new synthetic technologies has left us with methods unable to reach the inflection point.
Our goal is to transform materials discovery by developing a complex material thin film system that can attain 99% atomic ordering in today’s “too-complex” materials. This talk will highlight our progress in thin film growth via Sputter Beam Epitaxy, an approach combining the fabrication strengths of off-axis magnetron sputtering and molecular beam epitaxy.
Accelerated Stress Tests on Fuel Cell Cathode Catalysts: Thin Film (Ex-situ) Vs. Catalyst Layer (In-situ)
Authors: Rice Cynthia A. 
Published: February 2020

For proton exchange membrane fuel cells (PEMFC), cathode catalyst durability is presently a key limiting factor to commercialization for automotive applications. The oxygen reduction reaction takes place on the cathode – transforming O2 + 4H+ + 4e- to 2H2O. Degradation occurs during normal operational load profiles for idle-to-peak power transients (rapid stop-go drive cycles), as the cathode voltage quickly switches from 0.9-1.2V (idle) to ~0.6V (peak). Cathode catalyst durability is dependent upon multiple operational factors, including; potential limits, temperature, and pH. As a result of the transient potentials, the electrochemical surface area (ECSA) of the carbon supported platinum catalyst (Pt/C) is reduced, due to a combination of Pt dissolution, Pt particle growth (migration and/or redeposition), and carbon corrosion (Pt detachment). Typically, accelerated stress tests (AST) are performed on thin films to evaluate catalyst durability and decouple contributions from ancillary fuel cell materials and structures. The thin films consists of catalyst deposited on a conductive rotating disk electrode and analyzed in liquid electrolyte (HClO4 or H2SO4) vs. a separate counter and reference electrode – ex-situ to the actual PEMFC environment. This removes the additional complexity of the catalyst layers 3-deminsional structure (containing both Pt/C and proton conducting ionomer), diffusion media and membrane – in-situ.
The AST used in this study includes 25,000 potential cycles from idle to peak potential limits using either square or triangular waveforms (SW or TW, respectively) at 10 sec intervals, for both Pt/C thin films and catalyst layers. ECSA was measured periodically during the cycles, either by integration of the hydrogen desorption area or by CO stripping analysis. The following operational limits were used with a lower potential limit of 0.6V – several upper potential limits (UPL) from 0.9 to 1.2V, multiple temperature ranges between 25°C and 70°C, and different electrolyte pH ranges 0 to 1.
Ex-situ AST results in 0.1 M HClO4 at 70°C show that the loss in ECSA was affected by both the UPL and the potential wave profile. For the 0.9V UPL dominated by Pt dissolution, the SW was more aggressive than the TW, resulting in a 45.6% and 36.8% ECSA loss, respectively. While the higher UPL of 1.2V had nearly identical ECSA losses for both potential wave profiles of 89%, due to the dominance of carbon corrosion. Figure 1A shows the effects of pH on AST induced ECSA losses at room temperature for the UPL of 1.2V using a TW. The pH values correspond to different concentrations of HClO4 (0.1 M HClO4 = pH of 1). As the pH is lowered there is an increase in ECSA loss. In Figure 1B the TW was found to cause more catalyst degradation at lower pH values. This potentially could be related to in-situ relative humidity dependent degradation – to be further studied in-situ on a catalyst layer.

Figure 1