bluuebunny/crossref_metadata_2025 huggingface dataset:
Tailored Shapes of Fe-Ni-Co Nanowires
Authors: Podlaha Elizabeth , Li Deyang , Geng Xiaohua
Published: February 2020

Template-assisted, electrodeposited Fe-Ni-Co nanowires are reported targeting an Invar-like composition (e.g. Fe-rich, with < = 5 wt % Co) of interest for the materials low thermal expansion property and its ability to be magnetically aligned. The morphology of the nanowires is controlled by pulse and DC deposition conditions, and the electrolyte pH. Not only are nanotubes and solid wires fabricated, but also novel porous structures. The porous nanowires utilize the gas evolving side reaction as a dynamic template. Post treatment of nanowires via chemical etching, can also be used to shape the nanostructures. Two different approaches are examined, 1) creating dissimilar crystalline structure within the nanowire by the choice of the deposition operating conditions followed by a select etch in structure, and 2) introducing a sacrificial element, such as Cu, to selectively etch it in a passivating Fe-Ni-Co environment. Unique thinned nanowires and nanotips were designed.

The authors acknowledge the NIH and Roche Diagnostics for support of this project.
Template Free Photoelectrodeposition of Highly Periodic Three-Dimensional PbSe Nanostructures
Authors: Hamann Kathryn R , Carim Azhar I , Batara Nicolas A. , Thompson Jonathan R , Atwater Harry A , Lewis Nathan S
Published: February 2020

PbSe films with highly periodic nanoscale features were deposited over macroscale areas by utilizing a completely template-free photoelectrochemical deposition technique wherein the nature of the illumination directs the resultant material morphology. Highly-anisotropic lamellae were produced using linearly polarized light and the lamellae were oriented along the polarization axis; the pitch and width of these nanoscale features was observed to scale with the illumination wavelength. The deposition was simulated using a finite-difference time domain method to model light absorption and a Monte Carlo method for mass addition and the results of the simulation successfully reproduced the experimentally observed morphologies. The generation of polycrystalline PbSe was confirmed by energy dispersive X-ray spectroscopy and X-ray diffraction. Complete nanoscale patterning over square centimeter areas required only several minutes. Moreover, films were deposited from aqueous solution using oxidized precursors at room temperature and no lithographic processing or photomasks were utilized nor needed. Thus, this technique offers a method by which nanostructured semiconducting materials can be generated rapidly via a bottom-up approach capitalizing on the self-optimization of the material growth to maximize interfacial light absorption. Extension of this technique to generate other IV-VI as well as II-VI semiconductors is currently being explored.
(Invited) Electrodeposition in Tailored Nanochannels: A Rich Plattform to Study Nanowire Growth in Confinement and to Develop Stable Functional 3D Nanowire Architectures
Authors: Toimil-Molares Maria Eugenia
Published: February 2020

The implementation of nanowires and nanotubes for applications such as thermoelectrics, catalysis, plasmonics, or photoelectrochemical water splitting for hydrogen generation requires both, an excellent control on geometry, crystallinity and composition of the individual nanostructures, as well as its successful assembly into 2-D and 3-D architectures. Fabrication of 3-D nanowire superstructures by vapour–liquid–solid processes has been reported; however, it reveals a limited tunability of the relevant parameters.

This talk will illustrate how the unique combination of electrodeposition and tailored nanochannel templates provides an excellent platform (i) to study and control the nanowire growth, and (ii) to synthesize 3-D nanostructure assemblies and investigate their size-dependent properties.

Membranes with parallel nanochannels are fabricated by swift heavy ion irradiation and subsequent chemical etching. In addition, templates with interconnected tilted nanochannels are obtained by applying ion irradiation at several incident angles in consecutive steps. Nanochannel density and orientation, as well as diameter and geometry, are adjusted by the irradiation and etching conditions, respectively. Subsequent electrodeposition in the channels results in nanowire arrays and highly ordered 3-D nanowire ensembles of various materials. Recent developments achieved on the electrodeposition of metal (Au1-xAgx), semiconductor (ZnO and p-Cu2O) and semimetal (Sb) nanowire arrays and nanowire networks will be presented. Special emphasis will be given to the implementation of the nanowire assemblies in photoelectrochemical and thermoelectric devices, which is possible thanks to the flexibility and control offered by electrodeposition.
Electroreduction of Carbon Dioxide to Syngas: From Concept to Pilot Plant
Authors: Kenis Paul J.A.
Published: February 2020

Increasing evidence suggests that the unwanted effects of climate change, including global warming, rising sea levels, and erratic weather patterns are the result of the increasing atmospheric concentrations of carbon dioxide and other greenhouse gasses. Further development and integration of renewable but intermittent energy sources such as solar and wind, as well as enhancing energy efficiency in buildings and transportation applications will be critical to significantly reduce global CO2 emissions. An alternative strategy to reduce CO2 emissions is to use CO2as a feedstock in the production of chemicals.

The electrochemical reduction of CO2 into useful chemicals such as formic acid, carbon monoxide (CO), hydrocarbons, or alcohols has started to receive significant attention, both in academia and industry. Most research efforts over the last decade have focused on the development of increasingly better cathode catalyst for the efficient electrochemical reduction of CO2 to formic acid, CO, and other products. A few companies are trying to commercialize CO2 to formic acid, but the world market for formic acid is small. The bigger opportunities lie in conversion of CO2 to CO or syngas, as that product feds directly into the well-known Fischer-Tropsch for the production of chemical and fuels. Our group and others have advanced electrolysis of CO2to CO to the level where companies have started to look into scale up, including testing of the process in a pilot plant.

This presentation will summarize the development of suitable cathode catalysts for selective CO2 to CO conversion, but also point out the importance of developing suitable gas diffusion electrodes (given that the CO2 feed is a gas), and the tuning of the electrolyte composition to maximize performance. Furthermore, this presentation will cover the importance of optimizing the anode side, typically the oxygen evolution reaction, in order to achieve much better energetic efficiencies. In parallel with these experimental efforts we have pursued a techno-economic analysis as well as a life-cycle analysis of electroreduction to different products, including the separation steps needed before and after, to identify the most important areas that will need improvement to enhance economic feasibility and to ensure and maximize net negative greenhouse gas emissions.
Perspectives on Computational Analysis of Electrocatalysis: Stability and Activity Considerations in Catalyst Screening
Authors: Greeley Jeffrey
Published: February 2020

Advances in the theoretical understanding of interfacial electrochemistry have, over the past decade, permitted the extension of periodic Density Functional Theory studies, which have traditionally been applied to probe chemistry at gas/solid interfaces, to electrochemical systems where potential-dependent structural and chemical phase transformations occur at liquid/solid interfaces. Indeed, such techniques have been employed to study a surprisingly wide class of electrochemical processes, ranging from electrocatalysis to corrosion, and are now being used to identify promising candidates for new electrocatalytic materials.

In this talk, I will provide a brief overview of current approaches to computational screening of electrocatalysts, focusing in particular on the need to couple predictions of catalyst stability with traditional analyses of rates and activities. I will begin with a discussion of recent results in the computational screening of oxygen reduction (ORR) electrocatalysts, focusing on the large number of materials “tuning knobs” that have been explored via calculations for this chemistry. I will then describe very recent efforts to computationally probe catalytic properties of more structurally complex electrocatalysts, including bifunctional catalysts and mixed metal/oxide systems. For such catalysts, which are relevant for chemistries ranging from CO oxidation in acidic solutions to hydrogen evolution in alkaline solutions, prediction of materials structure and stability is an essential prerequisite to determination of rates and currents, and I will therefore focus on how techniques to effect stability predictions are being combined with traditional screening methods for these systems. I will close with a few perspectives on future directions for electrocatalyst screening efforts.
Electrochemical Atomic Layer Deposition: Self-Terminated Electrodeposition Reactions
Authors: Moffat Thomas P. , Liu Yihua , Ahn Sang Hyun , Ritzert Nicole L. , Wang Rongyue , Gillette Eleanor , Gokcen Dincer , Tan Haiyan , Hangarter Carlos , Bendersky Leonid , Bertocci Ugo , You Hoydoo
Published: February 2020

Development of a sustainable hydrogen economy based on water electrolysis and fuel cells is constrained by the performance, longevity and high cost of Pt group electrocatalysts. Important strategies for improving catalytic reactivity include alloying, forming bimetallic or alloyed surfaces, and engineering substrate–catalyst interactions. At the same time, significant effort is underway to minimize the loading of Pt group metals by examining new synthesis methods and electrode geometries. Of specific interest is atomic layer deposition (ALD) that can be used for growing ultrathin films to maximize utilization of rare, expensive metals and facilitate the exploration of bimetallic effects in electrocatalysis.

Recently, an inexpensive “wet form” of ALD based on self-terminated electrodeposition reactions was uncovered that enables controlled formation of ultrathin films of Pt, Ir and iron group metals and alloys thereof. The mechanism of self-terminated deposition reactions will be discussed and the utility of these films as bimetallic electrocatalysts will be demonstrated. For example, monolayer equivalent Pt and Ir films were found to match or exceed the best known specific HER/HOR activity for bulk polycrystalline Pt or Ir electrodes and thereby offer the promise of increasing the scalability of these important precious metals in energy conversion devices. The effectiveness of such reaction on a variety of different substrates will also be examined.
Electroless Deposition of Disordered RuO2 Nanoskins: An Example from the Fourth Quadrant of Electronic Materials
Authors: Rolison Debra R. , Osofsky Michael S. , Chervin Christopher N. , Pala Irina R. , Melinger Joseph S. , DeSario Paul A. , Donakowski Martin D. , Krowne Clifford M. , Owrutsky Jeffrey C. , Bussmann Konrad M. , Charipar Kristin M.
Published: February 2020

Our team at the Naval Research Laboratory has demonstrated that an ultrathin film of nanoscale, disordered ruthenium dioxide, designated RuO2 nanoskin, can be deposited from commercially available precursors onto metal, ceramic, semiconductor, polymer, and salt substrates using scalable, atom-efficient, low-temperature, liquid-phase, self-limiting electroless deposition. The electrical conductivity of the resulting nanoskins can be tuned over three orders of magnitude by calcining without ripening the particles comprising the film. On the basis of optical, electrical, structural, thermal, microscopic, mechanical, electrochemical, and chemical state measurements, we categorize this disordered, nanoscale oxide as a member of a rare quadrant of electronic materials: one that exhibits a high concentration of electronic carriers (n) of low mobility (m). The remarkable physicochemical properties of RuO2 nanoskins point to the importance of expressing functional materials in disordered, forms.
Interfacial Chemistry and Bulk Microstructure from in-Situ Small Angle Scattering
Authors: Bridges Craig A. , Sun Xiao-Guang , Jafta Charl , Heller William , He Lilin , Guo Bingkun , Paranthaman Mariappan Parans , Dai Sheng
Published: February 2020

To achieve higher energy density batteries while maintaining battery safety, better understanding is needed of processes such as solid-electrolyte interphase (SEI) formation due to electrolyte decomposition at the electrode surface. Research has historically been hindered by a lack of methods to directly probe electrochemical processes during battery cycling; more recently, several approaches have been developed to address this. We have developed a small-angle neutron scattering (SANS) based approach to observe electrochemical processes utilizing an ordered mesoporous hard carbon electrode with a high surface area that is of interest for high capacity, high power applications. The talk will present work on several electrolytes and modified electrodes examined by SANS - what has been learned about how the SEI forms and the microstructure of hard carbon electrodes changes during cycling, and what the implications are for battery design.
(Invited) Linking Advanced Characterization and Continuum Modeling to Understand Battery Behavior
Authors: Srinivasan Venkat
Published: February 2020

Frank McLarnon’s contribution in developing advanced optical and spectroscopic techniques over the past few decades have led to a deep understanding of how electrochemical processes occur. As we become more proficient in visualizing processes that occur in batteries in situ, we are challenged with offering hypotheses that explain the observables and help link the microscopic and spectroscopic information to the electrochemical performance. Continuum-scale mathematical models provide an ideal means of providing this link and is a useful way to test hypothesis.

In this talk, we will examine the role of continuum models in testing hypothesis and predicting performance, working with concert with experimental observations. We will use a few examples systems to establish the role of models. We will examine the growth of lithium dendrites and link the experimentally observed growth morphology to mechanical and electrochemical processes to help determine ways to stop dendrites. We will also examine the role of the experimentally determined 3D microstructure of porous battery cathodes in determine the performance limitations in cells. These examples will serve to highlight the critical role modeling plays in enhancing our understanding.

The figure below shows an example of such an approach where in situ x-ray tomography information (top panel) of dendrite growth provides critical information on the morphology change of the dendrite during deposition in polymer electrolytes. Using a continuum-scale model, we have shown that the change in shape of the dendrite is closely linked to the increasing compressive stress at the peak of the dendrite that retards deposition (bottom panel). Such a model can then be used to provide guidance on how materials can be tuned to prevent dendrite growth. More details of this work can be found at J. of Electrochem. Soc., 163 (10) A2216 (2016).

Figure 1
Electrodeposition of Li Metal Onto a Micro-Electrode in Various Electrolytes
Authors: Nishikawa Kei , Kanamura Kiyoshi
Published: February 2020

Li metal is very attractive candidate for next-generation rechargeable batteries because Li metal has very large theoretical capacity and the lowest standard electrode potential. However, Li metal forms dendrite very easily by repeating the electrodeposition and electrochemical dissolution. In general, the distribution of the current density will cause the metal dendrite formation in the electrochemical system. In case of Li metal electrode, SEI (solid electrolyte interphase) covered on the Li metal surface. The SEI layer is very important parameter for the morphological variation of electrodeposited Li metal. Many researches were conducted based on the surface chemistry in order to reveal the relationship between the nature of SEI layer and the morphology of electrodeposited Li metal. However, the distribution of the electrodeposited Li metal is an obstacle for the quantitative analysis in order to discuss the dendrite initiation and growth. In other words, the dendrite growth phenomenon is strongly localized, especially in cm-scale electrode.

In this study, micro-electrode was utilized to observe the morphological variation of electrodeposited Li metal. Ex-situ SEM observation was done to compare the morphology of Li metal in various kinds of electrolyte. The Pt wire with 10 or 20 mm diameter was covered by glass capillary, and the tip was polished very carefully. And then, Cu was electrodeposited onto the Pt micro-electrode because Pt forms alloy with Li. The Cu coated Pt micro-electrode was utilized as the working electrode, and counter electrode was Li metal in an electrochemical cell. Constant current electrodeposition was conducted to observe the electrodeposited Li metal. Applied current density was 2 mA/cm2. After the electrodeposition, the micro-electrode was rinsed with some solvents very carefully, and transferred to FE-SEM with transfer vessel without air exposure.

Figure 1 demonstrates the time variation of electrodeposited Li metal in 1M LiPF6-EC:DEC(1:1 volume) electrolyte. Although applied current density (2 mA/cm2) is quite large, Li metal electrodeposited onto the micro-electrode with very smooth morphology. Micro-electrode system can offer enough Li+ mass transfer to the electrode surface with semi-sphere diffusion mode. And LiPF6 salt supplies small amount of HF with hydrolysis reaction. HF can react with Li metal to LiF as uniform SEI layer on the electrodeposited Li metal surface. These are reason why the very smooth electrodeposited Li metal formed onto the micro-electrode. We will show not only FE-SEM images but also 3D images obtained by FIB-SEM system for electrodeposited Li metal from various electrolyte in this presentation.

Figure 1
Lithium Growth Mechanism at High Current Densities
Authors: Lindner Peter , Bauer Harald , Hackenberg Juergen , Ziemlich Winfrid
Published: February 2020

Due to the high energy density of lithium metal anode in the secondary battery much effort has been done to investigate lithium deposition. However, only few publications have been done to analyze the Lithium deposition at current densities (cd) of 5 mA/cm² and more, which are relevant for automotive applications. In this work we show time resolved behavior of lithium deposition with cd varied between 0.1-200 mA/cm². The experiments were made in a pseudo-two dimensional optical cell with a symmetric Lithium configuration. Electrolyte was a 1 mol/l solution of LiTFSI in PC:DC (1:1), at room temperature. The distance between anode and cathode was 1mm and active surface 6x10-4 cm².

While deposition at low cd led to a dendritic growth of Lithium, with a high current density 10 mA/cm² a homogenous dendritic sheath of lithium was observed. The dendrite growth mechanism was found to be time dependent and changes during the deposition while all external parameters (current, temperature,…) are kept constant. The growth behavior changes from a homogenously distributed dendritic growth at the beginning to the growth of distinct positions only in an advanced state of the deposition.

Optical and electrical signals were correlated in real-time during cycling. A strong indication is given for the formation of “death Lithium” for every cd.
Effect of Surface Properties of Titanium Anode on Surface Brightness of Electrodeposited Copper Foil
Authors: Lin Yen Chen , Yen Chih-Han , Dow Wei-Ping
Published: February 2020

Copper foil has been widely used for fabricating electronic products as conducting wires. Of course, it is also employed as the current collector of lithium ion battery (LIB). For the current collector of a LIB, the common copper foil is made by rolling approach. However, its cost is high although its performance is good. Alternatively, electrodeposited (ED) copper foil, which is cheaper than the rolled copper foil, is produced to replace the rolled copper foil. To meet the requirement of the current collector of a LIB, the surface brightness and crystalline structure of the ED copper foil has to be specifically made.

In this work, how to obtain a glossy and smooth surface of the ED copper foil is our target. According to papers(1, 2) the surface condition of the Ti anode for copper foil electrodeposition is critical. Herein, we designed two approaches to reveal which factor is significant if someone would like to obtain a glossy and smooth ED copper foil. One approach is physical, that is polish condition of the Ti anode; the other approach is chemical, that is etching condition of the Ti anode. The brightness of the ED copper foil was measured by a tool. The surface morphologies of the Ti anode and the ED copper foils were imaged using a scanning electron spectroscopy (SEM). The surface element on the processed Ti anode was analyzed by EDS. The copper deposition and oxidation (i.e., stripping) was examined using cyclic voltammetry (CV). The results show that chemical approach is more effective than physical approach to obtain a glossy and smooth ED copper foil. The result is interesting because it indicates that the surface oxidation condition is a key factor to form a glossy and smooth ED copper foil rather than surface roughness of the Ti anode.

Keywords: Copper foil, Lithium ion battery, Electrodeposition, Ti anode

References:

1. H. Kurihara, K. Kondo and Y. Okamoto, Journal of chemical engineering of Japan, 43, 612 (2010).

2. H. K. Chang, B.-H. Choe and J. K. Lee, Materials Science and Engineering: A, 409, 317 (2005).
Study on Separator for Alkaline Water Electrolysis
Authors: Manabe Akiyoshi , Domon Hiroki , Kosaka Junko , Okajima Takeyoshi , Ohsaka Takeo
Published: February 2020

Considering future hydrogen society without CO2 emission, water electrolysis will take an important position in total hydrogen technology chain. Alkaline water electrolysis (AWE) is one of the candidate technologies to produce hydrogen on a large scale from renewable energy. The performance of AWE process is mainly achieved by four factors, i.e., anode, cathode, separator and cell structure. Although the each factor affects mainly the cell voltage, separator has an effect for both cell voltage and generated gas purity. Therefore, in order to achieve high purity of the gas from the AWE electrolyzer, the characteristic or performance of separator is important in the system.

Our target is to achieve 1.80 V of cell voltage at 0.4 A/cm2, 80℃ and over 99.9% hydrogen purity. Many separators were screened. A separator of diaphragm type showed good performance for AWE. The evaluation of separator was carried out by using different sizes of cells such as 0.2, 1.0 and 16 dm2depending on the aim of evaluation. The structure of each test cell is based on zero-gap concept to reduce gas effect in the electrolysis.

The cell voltage of 16 dm2 bench cell was 1.81 V at current density 0.4 A/cm2, temperature 80℃ and hydrogen purity 99.95% and 1.94 V at current density 0.6 A/cm2, temperature 80℃ and hydrogen purity 99.96%. It was confirmed that only single side feeding to cathode is available for the cell operation without any serious problems under Δ300 mmH2O differential pressure (between anode chamber  and cathode chamber). The result indicates that cathode electrolyte can easily pass through the diaphragm from cathode side to anode side.

The cell equipped with diaphragm without hydrophilic treatment showed a large fluctuation in cell voltage. It suggests that hydrophilic treatment of membrane is very important factor to get steady operation in the actual large-scale plant. The flow rate of electrolyte (0.3 to 0.45 mL/min-cm2) does not dominate the purity of hydrogen gas produced. It was also confirmed that the diffusion amounts of gas through the diaphragm as gas (bubble) and solved species (gas) in the electrolyte are on the same level (H2 gas: dissolved H2 gas = 1:1.25).
Highly Active Nano-Perovskite Catalysts for Oxygen Evolution Reaction: Insights into Activity and Stability in Alkaline and Quasi-Neutral pH Electrolytes
Authors: Kim Baejung
Published: February 2020

The water splitting reaction requires effective electrocatalysts to facilitate efficient oxygen evolution reaction (OER), which suffers from a high overpotential. Among cost viable electrocatalysts, PrBaCo2O5+δ and Ba0.5Sr0.5Co0.8Fe0.2O2+δ are gaining attention for their high specific activities toward OER in alkaline water electrolysis. Here, nanoparticles of PrBaCo2O5+δ and Ba0.5Sr0.5Co0.8Fe0.2O2+δ were prepared using a scalable flame spray synthesis rendering significantly high mass activities, current densities improve by 10 and 50 times, respectively, than compared to those prepared via the state-of-the-art synthesis method. Furthermore, up to date, only their performances under alkaline conditions (pH 13 – 14) have been exclusively studied barring lower pH values. We highlight that the assessment of activity and stability of perovskite catalysts in a quasi-neutral pH value is absolutely necessary for an extension of application in co-electrolysis of water and carbon dioxide in generation of hydrocarbon fuels. Therefore, we investigate their electrocatalytic performances in a quasi-neutral electrolyte where PrBaCo2O5+δ reveals more than three-folds higher mass activity than Ba0.5Sr0.5Co0.8Fe0.2O2+δ. To the best of our knowledge, for the first time, we narrate the dependency of electrocatalytic behaviors on the electrolyte pH with respect to their thermodynamic stabilities obtained from DFT based Pourbaix diagrams.
Investigations on both Electroplating and Capacitive Removal of Lead from Waste Water
Authors: Blackwood Daniel J , Gui Yang
Published: February 2020

Heavy metals disposed to aquatic environments is always a major concern worldwide, Because of its adverse effects on human health and ecosystems.[1] Therefore, investigations on the removal of heavy metals from industrial waste water and other effluents are receiving considerable attention.

The contribution of this work is to obtain a series of optimized parameters, controlling a system combining capacitive desalination technique (CDI) with electrodeposition for lead ion removal, to achieve the goal of reducing waste streams in the region of 100 ppm to below 5 ppm; the legal limit in Singapore for discharge of industrial water into public sewers.

In addition, cyclic voltammery analysis was conducted from small scale standard three electrode systems to identify the relative contributions of pure electrical double layer charging and electrodeposition when the current passing through the electrodes. Further more, by designing experiments in the presence and absence of atmospheric CO2 we are also able to show that the formation of lead carbonates is detrimental to the release of lead compounds during the discharge stage of the operation.

Acknowledgment Funding for this work was provided by the Environment & Water Industry Programme Office under grant number 1301-IRIS-33.

References:

[1] L. Jarup, Hazards of heavy metal contamination, Br. Med. Bull. 68 (2003) pp.167-182

[2] Wills, R.G.A., Collins, J., Stratton-Campbell, D., Low, C.T.J., Pletcher, D. and Walsh, F.C.

(2010)Developments in the soluble lead-acid flow battery. Journal of Applied Electroche

mistry, 40, (5),955-965. (doi:10.1007/s10800-009-9815-4).
Shock Electrodialysis As an Aqueous Separation Platform
Authors: Conforti Kameron Michael , Schlumpberger Sven , Bazant Martin Z.
Published: February 2020

Efficiently separating water from its dissolved contents remains a pressing challenge with far-reaching impacts. The most natural application is the removal of salt and other toxins in water to make it suitable for drinking. In addition to removing impurities, separation technologies can be used to concentrate valuable species in an aqueous effluent stream in an industrial process. Shock electrodialysis (SED), a recently developed separation platform from our lab1–4, is well equipped to concentrate and separate salts, nanoparticles, wastes, charged species, and many uncharged particles in low salinity water. SED, much like electrodialysis (ED), passes an electric current perpendicular to flow in order to guide ions out of a purified stream of water and into a concentrated brine. To contrast ED, the separation of fresh and brine is not achieved by a physical barrier like a membrane. Instead, the streams are separated by a stable concentration “shock” that arises from passing overlimiting current (defined as current requiring ion transport faster than is possible by diffusion alone) between the electrodes. This shock is stable in flow and possible only because of the SED device’s carefully chosen porous media, which must be “leaky membranes” whose surface charge per volume is large enough to sustain over-limiting current (faster than diffusion) by electro-migration (surface conduction) and electro-osmotic flow (surface convection) but small enough to allow for strong salt depletion and “wave breaking” of the concentration profile. Using a combination of this technology with shock electrodeposition, another recent advance from our research lab5, it is possible to achieve the deionization of water without the costly water splitting reaction at the electrodes while collecting a significant portion of the impurities in a solid waste stream when removing certain metallic ions.

References

1. Deng, D. et al. Water purification by shock electrodialysis: Deionization, filtration, separation, and disinfection. Desalination
357, 77–83 (2015).

2. Schlumpberger, S., Lu, N. B., Suss, M. E. & Bazant, M. Z. Scalable and Continuous Water Deionization by Shock Electrodialysis. Environ. Sci. Technol. Lett.
2, 367–372 (2015).

3. Deng, D. et al. Overlimiting Current and Shock Electrodialysis in Porous Media. Langmuir
29, 16167–16177 (2013).

4. Bazant, M. Z., Dydek, E. V., Deng, D. & Mani, A. Method and apparatus for desalination and purification. (2014).

5. Han, J.-H., Wang, M., Bai, P., Brushett, F. R. & Bazant, M. Z. Dendrite Suppression by Shock Electrodeposition in Charged Porous Media. Sci. Rep.
6, 28054 (2016).
Continuous Electrochemical Reactor for Conversion of Biorefinery Lignin to Aromatic Compounds
Authors: NaderiNasrabadi Mahtab , Staser John A
Published: February 2020

Abstract

Lignin is one of the most abundant biopolymers on Earth, constituting about 20 to 30 percent of wood; it is one of the major waste materials of the pulp and paper industry and emerging biorefineries [1]. Utilization of lignin as a raw material for industrial chemicals would provide additional revenue streams for pulping mills and biorefineries, and especially in the case of the latter, reduce the overall cost of generating biofuel. Lignin depolymerization is the main approach to conversion of the biopolymer to value-added chemicals. It occurs by cleavage of C-C and C-O linkages between lignin units to produce low molecular weight aromatic compounds. However, the high molecular weight and three dimensional structure of lignin results in a high amount of energy to break down these linkages [4]. Electrochemical techniques applied to this problem could address issues like low selectivity toward desirable products, high energy consumption and low reaction rates.

This presentation will focus on our efforts to develop continuous electrochemical processes to convert biorefinery lignin to aromatic compounds useful to industry. We will discuss electrocatalyst development, product stream analysis techniques, and validation of a continuous process that leads to higher yield and selectivity toward useful aromatic compounds.

References:

[1] R. Behling, S. Valange, and G. Chatel., Heterogeneous Catalytic Oxidation for Lignin Valorization into Valuable Chemicals: What Results? What Limitations? What Trends?, Green Chem. (2015) 1.

[2] M.D. Kärkäs, B.S. Matsuura, T.M. Monos, G. Magallanes, C.R.J. Stephenson, Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future, Org. Biomol. Chem. (2016) 1853.

[3] B. M. Upton, A.M. Kasko, Strategies for the Conversion of Lignin to High-Value Polymeric Materials: Review and Perspective, Chem. Rev. (2016) 2275.

[4] Claudia Crestinia, Marcello Crucianellib, Marco Orlandic, Raffaele Saladinod, Oxidative strategies in lignin chemistry: A new environmental friendly approach for the functionalisation of lignin and lignocellulosic fibers, Catalysis Today 156 (2010) 8.
Accessing New Monomers from Biopriviledged Molecules By Coupling Metabolic Engineering and Electrosynthesis
Authors: Matthiesen John Edward , Abdolmohammadi Sanaz , Cochran Eric W. , Tessonnier Jean-Philippe
Published: February 2020

Recent progress in metabolic engineering has generated new microorganisms able to convert carbohydrates and waste lignin into biopriviledged molecules.1 One of these molecules, muconic acid, can be further diversified to adipic acid and terephthalic acid, which are central to the production of Nylon-6,6 and polyethylene terephthalate (PET). Its semi-hydrogenation also leads to new molecules such as trans-3-hexenedioic acid (3HDA), a compound that enables the synthesis of bio-advantaged Nylon-6,6. However, to achieve economically sustainable conversion, it is crucial to streamline the fermentation and downstream catalytic processing steps. This generates new challenges as biogenic impurities inherent to the fermentation broth can deactivate Pt-group metal catalysts.

An alternative approach would be to utilize novel conversion schemes using robust base metals that are stable in the presence of biogenic impurities.2 We show that electrosynthesis represents a promising approach for the direct processing of unpurified broths.2,3 The water, salts, and acidic impurities already present in the medium provide a suitable electrolyte, while protons in the solution provide the hydrogen required for the desired transformation. Muconic acid was converted to 3HDA with a 94% yield and 100% faradaic efficiency using lead (Pb) electrodes.4 Under these conditions, 3HDA can be produced at a competitive price of $2.00 kg-1. The reaction mechanism and the origin of the high selectivity to 3HDA will be discussed.

1. B.H. Shanks and P. Keeling, Bioprivileged Molecules: Creating Value from Biomass, Green Chem. 2017, advance article. https://dx.doi.org/10.1039/C7GC00296C

2. M. Suastegui, J. E. Matthiesen, J. M. Carraher, N. Hernandez, N. Rodriguez Quiroz, A. Okerlund, E. W. Cochran, Z. Shao, J.-P. Tessonnier, Combining Metabolic Engineering and Electrocatalysis: Application to the Production of Polyamides from Sugar, Angew. Chem. Int. Ed.,
2016, 55, 2368-2373. http://dx.doi.org/10.1002/anie.201509653

3. J. E. Matthiesen, J. M. Carraher, M. Vasiliu, D. A. Dixon, J.-P. Tessonnier, Electrochemical Conversion of Muconic Acid to Biobased Diacid Monomers, ACS Sustainable Chem. Eng.,
2016, 4, 3575-3585. http://dx.doi.org/10.1021/acssuschemeng.6b00679

4. J. E. Matthiesen, M. Suástegui, Y. Wu, M. Viswanathan, Y. Qu, M. Cao, N. Rodriguez-Quiroz, A. Okerlund, G. Kraus, D. R. Raman, Z. Shao, J.-P. Tessonnier, Electrochemical Conversion of Biologically Produced Muconic Acid: Key Considerations for Scale-up and Corresponding Technoeconomic Analysis, ACS Sustainable Chem. Eng.,
2016, 12, 7098-7109. http://dx.doi.org/10.1021/acssuschemeng.6b01981
Selective Hydrogenations in Proton Exchange Membrane Reactor
Authors: Carl Sarah , Waldrop Krysta , Pintauro Peter N , Thompson Levi T
Published: February 2020

With the increased demand for environmentally sustainable fuels and chemicals, interest in the conversion of biomass conversion into value-added chemicals and high density fuels has increased. Traditional biomass upgrading processes are carried out thermocatalytically at high temperatures and pressures, and often yield low selectivities. In contrast, electrocatalytic process can be performed at low temperatures and pressures and can utilize renewable electricity. In addition for hydrogenation reactions, high hydrogen concentrations can be achieved.

The key to controlling the selectivity of electrocatalytic hydrogenations is identifying appropriate cathode materials. Our group has been exploring the use of early trasition metal carbide based materials for a variety of electrocatalytic and catalytic reactions. Significant improvements in product yields and selectivities have been demonstrated for the electrocatalytic hydrogenation of triglycerides using W2C and Pd/W2C materials. These improved rates have been linked to hydrogen spillover and synergistic effects between Pd and the W2C support.

The aim of research described in this paper was to investigate the use of a proton exchange membrane reactor for the electrocatalytic hydrogenation of model biomass species including furfural and crotonaldehyde, and compare the results with those from conventional thermocatalytic processes. Expanding upon previous work, the cathode catalyst consisted of a metal active for hydrogenation (Pd, Co, and Ni) supported on traditional thermocatalyst supports (SiO2 and Al2O3), a traditional electrocatalyst supports (carbon), and Mo2C, a conductive thermocatalyst that has been extensively studied for various hydrogenation reactions. Structural and compositional properties of the materials were linked to their hydrogenation rates and selectivities.
Towards Sustainable Fuels from Biomass Using Fast Pyrolysis and Electrocatalysis in Regional Depots
Authors: Saffron Christopher M. , Das Sabyasachi , Fasahati Peyman , Garedew Mahlet , Lam Chun Ho , Jackson James E.
Published: February 2020

Novel routes to renewable hydrocarbon fuels are needed to provide transportation energy for operating the U.S. automobile fleet and to reduce atmospheric carbon concentrations. Biomass-to-liquid technologies are necessary components of future bioenergy systems that are used instead of fossil systems to minimize climate change. Fast pyrolysis is a thermochemical technology that converts biomass into liquid fuel intermediates while producing biochar, a co-product that sequesters carbon when land applied. Though biochar is potentially of great benefit to the environment, the liquid intermediate made by pyrolysis, known as bio-oil, requires significant upgrading to meet the standards that are currently imposed on gasoline and diesel fuel. Following biomass deconstruction by fast pyrolysis at regional depots, electrocatalytic hydrogenation and deoxygenation (ECH) is proposed to partially upgrade bio-oil to create a stable intermediate with properties superior to raw bio-oil. Decentralized and distributed systems of this kind will allow for optimizing the balance of “economies of scale” and “economies of transportation,” while valorising agricultural commodities for rural prosperity. Subsequent hydroprocessing at centralized refineries, possibly using hydrogen from wind- or solar-driven electrolysis, creates the finished fuel. By reactively stabilizing bio-oil and increasing its energy content, ECH could be a foundational technology for this novel bioenergy system that is capable of significant decarbonization of the terrestrial atmosphere.
Functionality Impacts on Reaction Rates for Simple Mixtures of Aldehydes and Ketones
Authors: Holladay Jamelyn , Lopez Ruiz Juan A , Lilga Michael , Padmaperuma Asanga , Akhade Sneha
Published: February 2020

In recent years there has been growing interest in using electrochemical methods for hydrogenation of organic molecules. Conventional hydrogenation technologies require elevated temperatures and externally supplied high pressure hydrogen; however, the same reactions can be performed using an electrochemical reactor at close to room temperature and with no externally supplied hydrogen. In this work, we present our research examining the selective hydrogenation of aldehydes and ketones to alcohols. Specifically, we studied the hydrogenation of benzaldehyde, acetophenone, and vanillin, and how the different group functionalities impacts the catalytic activity. These experiments were performed in a flow-cells using with palladium catalyst on the cathode. In particular, we studied the effect of concentration and voltage on the current, Faraday efficiency, and catalytic activity for the electrochemical reduction of organic molecules at room temperature. Promising results have been observed where hydrogenation has been found. A description of work conducted and discussion of results will be presented.
Environmental Impact and Speciation Analysis of Chemical Mechanical Planarization (CMP) Waste Following GaAs Polishing
Authors: Crawford Steven , Aravamudhan Shyam
Published: February 2020

Chemical Mechanical Planarization (CMP) is a key enabling process used in semiconductor manufacturing to achieve local and global planarization of layers. Contemporary CMP process use nanoparticle slurries for the chemical and mechanical removal of material. As traditional silicon nears its scaling limits, next-generation devices will require the use of III-V materials such as Gallium Arsenide (GaAs). Planarization of GaAs increases Ga and As levels in wastewater, influencing the potential for environmental safety and health (ESH) concerns. Little is known about the environmental fate, behavior, and biological impact of this waste. Specific As species have vastly different magnitudes of toxicity. For example, inorganic As is more toxic than organic species and As(III) is much more toxic than As(V). As(III) is also more difficult to remove from wastewater and is typically oxidized to As(V) before removal. Knowing which specific As species are present in GaAs CMP waste is important for waste treatment and discharge. By measuring As species from a variety of GaAs CMP process conditions, we can discern the key factors affecting the balance of As(III) and As(V) in the CMP waste. In this work, we report on the ESH impacts of GaAs CMP waste, specifically on the (a) presence and speciation of Arsenic in the wastewater effluent; (b) presence and condition of Gallium; (c) physicochemical properties of the slurry nanoparticles after polishing; (d) effect of the slurry on typical oxidation methods and (e) effect of collected CMP wastes on human health, primarily cytotoxicity. The results from this research will help determine the specific effects of CMP slurry and processing conditions on wastewater containing elevated levels of Arsenic as well as provide insight on the type and relevance of remediation methods.

Figure 1
(Invited) Industry Perspectives on Atomic Layer Etching
Authors: Kanarik Keren J.
Published: February 2020

This presentation will describe the industry perspectives on atomic layer etching (ALE), a technique that is rapidly growing as an enabling technique with atomic scale fidelity in the fabrication of modern nanometer-sized electronics with features at 10 nm and below (1).

K.J. Kanarik, T. Lill, E. Hudson, S. Tan, S. Sriraman, J. Marks, V. Vahedi, R.A. Gottscho; J. Vac. Sci. Technol. A 33, 020802 (2015).
(Invited) Molecular Layer Deposition from Dissolved Precursors
Authors: Fichtner Johannes , Wu Yanlin , Hitzenberger Jakob , Drewello Thomas , Bachmann Julien
Published: February 2020

We propose and demonstrate a novel thin film deposition technique by transferring the principles of atomic layer deposition (ALD), known with gaseous precursors, towards precursors dissolved in a liquid. The technique can also be considered as a generalization of already established methods such as the ‘layer by layer’ growth of polyelectrolytes, the ‘successive ion layer adsorption and reaction’ (SILAR), and even the solid-phase peptide synthesis. 'Solution ALD' (sALD) shares the fundamental properties of standard ‘gas ALD’ (gALD), in particular the self-limiting surface chemistry and the ability to coat deep pores in a conformal manner. Furthermore, standard gALD reactions behave similarly when transferred into sALD mode. However, sALD also offers novel opportunities by overcoming the need for volatile and thermally robust precursors. To illustrate this, we establish sALD procedures for depositing films of MgO based on the hydrolysis of a Grignard reagent, and of a polyamine exploiting a strategy of protection, deprotection and activation that is standard in organic synthesis. Those two examples highlight how ionic, polar, or high-molecular weight precursors that only exist in the condensed phase are now rendered amenable to being utilized in surface-controlled thin film formation by sALD for depositing materials that would otherwise be more difficult or more expensive to achieve by gALD.

Figure 1
Synthesis of ALD Iridium Thin Films on Silicon and Monel K-500 Steel Substrates
Authors: Oelslager Peter John , Baumgart Helmut
Published: February 2020

Iridium (Ir) thin films have been extensively investigated for a variety of applications. Ir is a potential optical material for Fresnel zone X-ray microchannel plates, and inductive grid filters. It is also a noble metal making it well suited to corrosion resistance in harsh environments

Atomic Layer Deposition (ALD) is considered a special case of chemical vapor deposition (CVD) in that two different chemical precursor materials are alternately introduced into a vacuum chamber where a chemical reaction occurs on the surface of the substrate. This method of thin film growth is self-limiting and conformal and consequently results in precise layer thickness control, stoichiometry, composition, and uniformity across a large surface area. Advantages that are unique to ALD include the ability to grow conformal thin films across complex geometries, and the relatively low temperatures required to achieve film growth.

In this work, iridium metal films were synthesized on silicon (Si) and Monel K-500 alloy substrates by ALD using Iridium (III) acetylacetonate known as Ir(acac)3 or [CH3COCH=C(O-)CH3]3 Ir as precursor 1, and industrial grade O2 as oxidizing reactant. The solid Ir precursor was heated to 150 °C, and the substrate temperature was varied to establish an optimum growth window. The lowest temperature in which Ir growth was found is 200 °C, and the thin film growth rate increased as a function of temperature up to 250 °C. Higher temperatures have not yet been attempted due to equipment constraints. The Monel K-500 steel alloy flat discs were cut from commercially available Monel K-500 bars of ~1 inch diameter.

In this study we report on the successful synthesis of Ir films on Si and Monel K-500 substrates. Detailed characterization has been performed using X-ray diffraction (XRD) techniques, atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM) of samples which have been notched with focused ion beam (FIB) techniques for cross-sectional film thickness measurements as revealed in Figure 1. The polycrystalline ALD Iridium film exhibited good chemisorption and adhesion to native oxide covered Si substrates, with hydroxyl surface termination. However even with the absence of a SiO2 surface film, the ALD synthesis of Iridium metal films worked equally well on the Monel K-500 steel alloy flat disc substrates and yielded excellent surface coverage.