bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Dewatering of Cellulosic Nanomaterials
Authors: Vijapur Santosh H. , Hall Timothy D. , Taylor E. J. , Inman Maria , Snyder Stephen , Nelson Kim 
Published: February 2020

Cellulosic nanomaterials exhibit great potential in various applications due to their unique properties, abundant availability, and low production cost. Although cost effective to produce it is costly to ship, primarily due to the excess of water (>95 wt.%) in growth media necessary to produce the cellulosic nanomaterials. Therefore, a need has been identified by cellulosic material providers to develop energy-efficient, dewatering or drying of cellulosic nanomaterials, “as cellulosic nanomaterials are not economical to ship long distances while containing significant water content”. Moreover, the dewatered or dried cellulosic nanomaterials should be readily re-dispersed in water without any changes in its functional properties.
Faraday Technology in collaboration with AVAPCO, answer this need by developing an economical manufacturing method and apparatus for electrochemical dewatering of cellulosic nanomaterials including cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs). Specifically, our innovation is directed towards dewatering of CNCs and CNFs, not drying. AVAPCO has indicated that dewatering to 20-30 wt.% solids would be the end product for numerous applications such as cosmetics and paper processing. Using innovative reactor designs, we demonstrated the feasibility of a cost-effective, industrially viable, and energy efficient ElectroDewatering approach capable of generating 20 wt.% final solids, that was rehydrated under vortex and confirmed for re-dispersibility. Material properties (structure, particle size) were maintained by the dewatered cellulosic nanomaterials. Implementing sophisticated electric fields, we reduced energy use by 50% compared to conventional constant voltage approaches at similar or higher dewatering performance. Specifically, this talk will discuss the results of these advancements.

Acknowledgements: The financial support of DOE Contract No. DE-SC0018787 is acknowledged.
Pulse Reverse Current Cr+3 Deposition for Wear Applications
Authors: Hall Timothy D. , Taylor E. J. , Inman Maria , Snyder Stephen , Xu Jing , Radhakrishnan Rajeswaran 
Published: February 2020

Faraday Technology Inc. is a research, development and engineering firm developing electrochemical innovations based has pulse/pulse reverse electrolytic principles [1]. One of Faraday’s current activities is directed towards the development of an innovative functional REACH compliant chrome plating process based on a trivalent chromium electrolyte to replace hexavalent chromium plating. Hexavalent chromium plating has been used for many decades to provide hard, durable coatings with excellent wear and corrosion resistance properties. However, hexavalent chromium has come under increasing scrutiny due to the toxic nature of the bath, effects on the environment, and workers’ health. Faraday has demonstrated that the chrome coatings prepared using the FARADAYIC(R) Process have equivalent functional properties to the coatings produced with a hexavalent chromium bath. The data demonstrates equivalent or superior: 1) plating rate, 2) Knoop hardness, 3) current efficiency, 4) hydrogen embrittlement behavior, 5) adhesion, 6) corrosion resistance, 7) porosity, 8) thickness, 9) Taber Abrasion, Ball on Flat Reciprocating and Dithering wear resistance, and with no hexavalent chromium formation in the bath.
Therefore, this paper will discuss the 2013 EPA Green Chemistry Challenge Award winning work on the development of a REACH compliant functional trivalent chromium plating process from a single, simple-to-control trivalent-based electrolyte to replace hexavalent chromium plating. Furthermore, it will specifically discuss electrochemical deposition approaches to improve the wear index and microstructure of the coating.

Acknowledgements: This study is supported by the US Army (W911NF-11-2-0014) and private sources.
[1] E. J. Taylor “Adventures in Pulse/Pulse Reverse Electrolytic Processes: Explorations and Applications in Surface Finishing” J. Applied Surface Finsihing,
3(4), 178-189 (2008).
Pulse Reverse Alloy Plating for Increased Lifetimes for Biocombustors
Authors: Xu Jing , Hall Timothy D. , Vijapur Santosh H. , Wang Dan , Taylor E. J. , Inman Maria , Snyder Stephen , Brady Michael 
Published: February 2020

Biomass embodies tremendous potential as a renewable energy resource. According to the biomass Thermal Energy Council (BTEC), biomass energy is renewable, carbon neutral, domestic and technologically mature. In addition, the low cost per BTU of wood chips and pellets relative to fossil fuels makes biomass an attractive thermal energy source. Furthermore, ~7% of global energy consumption comprises small-scale biomass combustion,[1] representing a tremendous market for technologies that facilitate enhanced biomass utilization. However, a major challenge associated with utilization of biomass is its combustion behavior. The moisture content, chemical composition, and combustion efficiency varies depending on the source of biomass. Small scale biomass combustors (Figure 1) which for cost reasons are often constructed of mild or low-alloy steels, during operation are subjected to corrosive environments which include alkali halides (borne, e.g., by fly ash particulates), mineral/halogen acids and water; as well as various others such as sulfur and nitrogen oxides. There is a need to create more efficient, longer lasting, cleaner, and cost effective cookstoves for use in burning biomaterials. The materials used for cookstoves must improve burning efficiency, must be able to operate at higher temperatures, and should be low cost material systems to durably perform in the corrosive environments.
Within this context, Faraday Technology is working on developing low cost and high value corrosion-resistant alloy coatings for existing bio-combustors or lower cost steels with the goal of increasing their functional lifetime, while reducing the component cost. The manufacturing process involves electrodeposition of binary/ternary/quaternary alloys consisting of [Ni/Co]-Cr-[Mo/Fe] onto a low cost substrate and subsequent accelerated high temperature corrosion evaluation. A wide array of electrolytes and processing parameters were evaluated in order to understand these effects on the deposit composition, structure, and high-temperature corrosion resistance properties towards the goal of developing an ideal alloy coating. Specifically, 100 wt% Cr, 7 wt% Co- 93 wt% Cr binary and 15 wt% Ni – 20 wt% Cr – 55 wt% Co (NiCoCr) ternary alloy coatings demonstrated enhanced corrosion resistance when exposed to an aggressive environment (~700°C, 1000 hr, coating surface salted with ~1 mg/cm2 every 100 hours). When compared to the SS base material the Cr/CoCr alloy coatings exhibited effective protection to the substrate and over 10 times lifetime improvement to its base material.

Acknowledgements: The financial support of DOE Contract No. DE-SC0013870 is acknowledged.
[1] Biomass Production Now 10 Percent of World Energy, http://www.realclearenergy.org/charticles/2013/09/26/biomass_production_now_10_percent_of_world_energy_107257.html. Accessed 12 Jan 2015.

Figure 1
Influence of Pulse Parameters on a b Cuzn Alloys Electrodeposited Coatings
Authors: Dridi Amina , Dhouibi Leila , Hihn Jean-Yves , Bercot Patrice , Rezrazi El-Mustafa , Sassi Wafa 
Published: February 2020

Cu-Zn alloys is the most manufactured copper alloy in the word since it offers a wide range of properties depending on its zinc content. Although brass plating has been studied since 1841 by Ruoltz, and despite several studies devoted process improvement, CuZn coatings from non-cyanide baths shows low reproducibility, poor adhesion, inhomogeneous color and frequently cannot be deposited directly on steel. These problems are mainly attributed to an unusual crystalline phase distribution[1] [2]. Therefore, to obtain a higher quality of metallic electrodeposited alloy, it is mandatory to control the activity of the nobler ion in the solution, which is much more likely to be reduce. To that end, copper and zinc reduction potentials have to be bring closer by the use of a complexing agent of the copper ions. An electrolyte with a low citrate concentration has been developed and its electrochemical behavior extensively studied [3]. Varying Citrate concentrations will influence zinc electrodeposition and bath stability, giving the hand of the control of alloy element content. For the optimum conditions, CuZn coatings were obtained in a large range of Zn content (from 11% to 100%) as a function of Zn concentration and current density. Crystalline structures of the α β brass deposits were then identified in the range of 35% to 45% in Zn content, in order to be compared to commercial cast brass. The present study discusses the effect of pulse current for a selection of electrolytes, at the optimum of copper and citrate concentration. Wave modulation is investigated in order to compare Zn content and phase distribution for the same average current density. A particular focus was made on the quantification by XRD phase determination and its comparison with anodic dissolution. The best conditions have been tested on larger samples, to check adherence, homogeneity and to try to reach a maximum coating thickness and the right physical aspect than for the cast brass alloys.
[1] J.C. Ballesteros, L.M. Torres-Martínez, I. Juárez-Ramírez, G. Trejo, Y. Meas, Study of the electrochemical co-reduction of Cu2+ and Zn2+ ions from an alkaline non-cyanide solution containing glycine, J. Electroanal. Chem. 727 (2014) 104–112. doi:10.1016/J.JELECHEM.2014.04.020.
[2] T. Vagramyan, J.S.L. Leach, J.R. Moon, On the problems of electrodepositing brass from non-cyanide electrolytes, Electrochim. Acta. 24 (1979) 231–236. doi:10.1016/0013-4686(79)80030-4.
[3] A. Dridi, L. Dhouibi, J.Y. Hihn, P. Berçot, W. Sassi, E.M. Rezrazi, Study of the influence of complexes stability on the kinetic of CuZn electroplating in a citrate bath, Submitted Electrochim. Acta.

Figure 1
Insights Onto the Active Sites and Reactivity of Metal-Doped Carbonaceous Electrocatalysts for the CO2 Reduction Reaction
Authors: Asset Tristan , Matanovic Ivana , Chen Yechuan , Artyushkova Kateryna , Atanassov Plamen 
Published: February 2020

The CO2 valorization, i.e. its use in various electrochemical processes resulting in the production of carbon-based fuels and value-added chemicals, is of critical importance. Hence, the CO2 reduction reaction (CO2RR) has been widely investigated on electrocatalysts ranging from Cu-based nanostructures to carbonaceous materials. The latter often consist of carbon with atomically dispersed nitrogen and metals atoms (M-N-C, see Figure 1c). Such materials have been discussed in the literature, mostly using Fe as the metallic element 1 (but also Mn, Ni, Co and Cu 2–4), thus providing insights onto this family of electrocatalysts reactivity. But most of those electrocatalysts, as a result of their synthesis process, presents unwanted metallic contaminants 2. Here, we synthesized M-N-C electrocatalysts (with M = Cr, Mn, Fe, Co, Ni, Cu & Zn) using the sacrificial support method, that resulted into non-contaminated M-N-C materials. We then combined electrochemistry and density functional theory to separate the electrocatalysts in several categories, based on their COads binding strength. The strong COads binder electrocatalysts (e.g. Cr, Mn and Fe-N-C) achieved a Faradaic efficiency up to 50% at 0.35 V vs. RHE (at pH = 7.5, in 0.1 M phosphate buffer), as well as a metal-free electrocatalyst synthesized by the same method. This phenomenon was further investigated using near-ambient pressure XPS, which evidenced that the preferential adsorption site for CO2 was dependent of the metallic element nature: for Fe-N-C, the CO2 preferentially adsorb on pyridinic and hydrogenated (pyrrolic) nitrogen moieties (see Figure 1), hence evidencing the key role played by said moieties in the reactivity of the M-N-C electrocatalysts for the CO2RR.
(1) Varela, A. S.; Ju, W.; Strasser, P. Adv.
Energy Mater.
2018, 8 (30), 1–35; (2) Ju, W.; Bagger, A.; Hao, G. P.; Varela, A. S.; Sinev, I.; Bon, V.; Roldan Cuenya, B.; Kaskel, S.; Rossmeisl, J.; Strasser, P. Nat.
Commun.
2017, 8 (1), 1–9; (3) Varela, A. S.; Ranjbar Sahraie, N.; Steinberg, J.; Ju, W.; Oh, H. S.; Strasser, P. Angew.
Chemie - Int. Ed.
2015, 54 (37), 10758–10762; (4) Hu, X. M.; Hval, H. H.; Bjerglund, E. T.; Dalgaard, K. J.; Madsen, M. R.; Pohl, M. M.; Welter, E.; Lamagni, P.; Buhl, K. B.; Bremholm, M.; Beller, M.; Pedersen, S. U.; Skrydstrup, T.; Daasbjerg, K. ACS Catal.
2018, 8 (7), 6255–6264.

Figure 1
Low-Overpotential Electrochemical Reduction of CO2 to Formic Acid on Surface-Modified Doped Tin Oxide Pellets
Authors: Abdul Emmanuel Oluwaseun , Pitts Jason , Rajput Deepak , Rananavare Shankar 
Published: February 2020

Gas sensors fabricated with antimony doped tin oxide (ATO) nanomaterials exhibit remarkable sensitivity for detecting oxidizing and reducing gases. This study highlights the enhanced selectivity and stability of the porous ATO nanomaterial electrode made for electrochemical reduction of CO2 in aqueous media. During electrochemical reduction, these electrodes prepared from compressed powders tend to crumble within a few hours in aqueous media. To overcome this electrode disintegration effect, we modified the surface of the doped tin-Oxide nanoparticles and nanowires with Nafion and a dipodal silane (1,2-Bis(triethoxysilyl)ethane). The electrode characterization studies include Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). Scanning electron microscopic investigation of electrode surface morphology and roughness before and after electrochemical CO2 reduction for derivatized and underivatized electrode revealed lower surface roughness for former than the latter.
The derivatized electrodes allowed CO2 electrochemical reduction at low overpotentials and high current density without any electrode crumbling over more than 24 hours of continuous operation. Formate/formic acid and methanol were the major products of reduction at electrode potentials ranging from -0.4 to -1.0V vs. RHE in the CO2 saturated 0.1M KHCO3 electrolyte. Higher current density and Faradaic Efficiency of formic acid was observed when compared to planar tin electrode materials and tin oxide nanoparticles deposited on FTO glass.
Between Physical Complexity and Simplicity: Nailing Down the Cathodic Activation Overpotential in a Small-Scale PEM Fuel Cell
Authors: Gerling Christophe , Hanauer Matthias , Berner Ulrich , Friedrich K. Andreas 
Published: February 2020

Understanding the kinetics of polymer electrolyte fuel cells (PEFC) remains a key issue for the optimization of the catalyst layer structure with respect to fuel cell performance and ageing.
In this study, firstly the impact of hydrogen crossover from anode to cathode through the membrane on the measurable open circuit voltage (OCV) is analyzed extensively. For this purpose, all the other parasitic reactions like platinum oxide formation or carbon corrosion are neglected in a first approach and the influences of the operating conditions on the crossover flux by means of voltammetry measurements and also mass spectrometry in the cathode exhaust gas are examined. These experimental results yield an efficient parameterization of the crossover rate. Incorporated into a physical 1D through-plane cell simulation model, it allows for consistent predictions at and close to OCV conditions.
Subsequently, the activation overpotential is parameterized experimentally thanks to electrochemical impedance spectroscopy on a 25 cm2 cell with a straight parallel channel flowfield under differential conditions. Therefore, spectra are recorded for a large range of conditions (Fig. 1a) and the distribution of relaxation times (DRT) is evaluated (Fig. 1b). As a result, an equivalent circuit is set up. Hence, it is possible to fit the experimental data and to extract the kinetic parameters for our model, as functions of electrical load, oxygen partial pressure and temperature. We finally use this extensive dataset for comparing different approaches for modelling the oxygen reduction reaction (ORR) on platinum, ranging from single-step Butler-Volmer kinetics to advanced microkinetic models that take into account the intermediates of the ORR and thereby also the potential dependent surface coverage of the electrode [1-2].
References:

Huang, J. Zhang, M. Eikerling, Phys. Chem. Chem. Phys., 2018, 20, 11776

Holewinski, S. Linic, J. Electrochem. Soc., 159 (11) H864-H870 (2012)

Figure 1
(Invited) Exploring Sub-Second and Sub-Micron X-Ray Tomographic Imaging of Liquid Water in PEFC Gas Diffusion Layers
Authors: Xu Hong , Marone Federica , Nagashima Shinya , Nguyen Hai , Kishita Keisuke , Büchi Felix N. , Eller Jens 
Published: February 2020

In the last decade X-ray tomographic microscopy (XTM) has become a powerful 3D characterization technique for polymer electrolyte fuel cells (PEFCs). Extensive work has been implemented to characterize the gas diffusion layer's (GDL) microstructure and its influence on gas phase transport, degradation phenomena within the membrane or catalyst layer, the wetting behavior of GDLs, as well as the water distribution during cell operation. Especially sub-second operando XTM [1] is essential to enable the fundamental understanding of the water transport modes in the GDL which is vitally important for improving PEFCs performance, cost and durability. Thanks to recent microscope upgrades and the use of a wider energy range of the synchrotron radiation it is meanwhile possible to realize operando XTM scans of PEFCs with scan times of 0.1 s to 0.25 s at voxel sizes of 2.75 µm [2] or 0.4 µm, respectively, at the TOMCAT beamline of the Swiss Light Source at Paul Scherrer Institut (PSI). This presentation will give insights into these recent achievements and discuss selected case studies benefiting from the improved temporal and spatial resolution.
References
[1] J. Eller, F. Marone, F. N. Büchi, ECS Trans. 69(17), 523–531 (2015).
[2] M. Bührer, M. Stampanoni, X. Rochet, F. Büchi, J. Eller, F. Marone, J. Synchrotron Rad., (accepted).
Multiwalled Carbon Nanotubes As Non-Precious Metal Catalyst for the Oxygen Reduction Reaction
Authors: Kübler Markus , Theis Pascal , Ni Lingmei , Wagner Stephan , Jurzinsky Tilman , Kramm Ulrike Ingrid 
Published: February 2020

Fuel cells are regarded as environmentally friendly energy converters. This, in combination with national and global intentions of energy transition from fossil based resources to renewable ones, makes fuel cells a possible key technology regarding the future energy economy. Because of their advanced state of development, proton exchange membrane fuel cells (PEMFCs) are considered to be the most promising type of fuel cells in terms of commercial use in automotive propulsion. Nevertheless, the high requirements of precious platinum metal for the cathodic oxygen reduction reaction (ORR) is one major reason that still prevents a wide-spread use of this technology to this day. A promising alternative to platinum based catalysts are the so-called non-precious metal based materials. To this day, these catalysts already achieve high current density during PEMFC operation but still need major improvements regarding their durability.
In this work, the preparation and characteristics of nanotube based non-precious metal catalysts for the ORR are presented. For the commonly applied platinum based ORR catalysts the positive impact on durability and activity of using carbon nanotubes (CNTs) as carbon support has already widely been proven [1-3]. Here, three different catalyst preparations are presented. First, utilization of commercially available CNTs together with Fe-phenathroline leads to catalyst where FeNxCy moieties are present in-between the CNTs. Secondly, a preceding surface modification step of the commercially available CNTs leads to a material with the active sides directly attached onto the CNTs surface. The third preparation route gives a material where the FeNxCy moieties are directly incorporated into the nanotubes wall. TEM pictures are presented in order to show the structural morphology of the resulting catalysts and the nature of the iron nitrogen active sides is studied via Mößbauer spectroscopy. ORR activity and durability of the resulting nanotube based materials in acidic electrolyte is investigated. PEMFC performance tests clearly show that the connection between active side and nanotube play a crucial role for the activity of the catalyst. Hence, a significantly enhanced performance is found for the catalyst with the active sides incorporated into the nanotube walls.
References:
[1] X. Wang, W. Li et al., Journal of Power Sources
158 (2006) 154-159.
[2] F. Hasché, M. Oezaslan et al., Phys Chem Chem Phys
12 (2010) 15251-15258.
[3] T. Maiyalagan, B. Viswanathan et al., Electrochem. Comm.
7 (2005) 905-912.
Molten Hydroxide Dual-Phase Membranes for Intermediate-Temperature Fuel Cells
Authors: Vedharathinam Vedasri , Ivanovskaya Anna N , Cerón Maira R. , Campbell Patrick G. , Elangovan S , Hartvigsen Joseph J , Frost Lyman J 
Published: February 2020

Anion exchange membrane (AEM) fuel cells are sought after due to its enabled adoption of non-precious metals as electrocatalysts and enhanced reaction kinetics at high pH conditions[1]. Typical polymer membranes contain quaternary ammonium or phosphonium group polymers that conduct ions at temperature below 90°C[2], limiting their applications at elevated temperatures. Nevertheless, elevated temperature operations allow for improved electrode kinetics, system efficiency and simplified heat management. Hence, there is a need to develop hydroxide ion conducting membranes that are chemically and mechanically stable and can operate at intermediate temperature ranges (150 - 400°C) without compromising its ionic conductivity. Here we report a novel hydroxide-ceramic dual-phase (HCDP) membrane technology that utilizes molten alkaline hydroxides (e.g. sodium, potassium, and lithium) impregnated into the porous zirconia matrix[3]. When using air as oxidant, hydroxide ions react with from air to form carbonates leading to performance degradation of the fuel cell due to loss of ionic conductivity. The poisoning effects are rapid and severe, necessitating the use of pure oxygen instead of air as cathode feed. Our proposed technology overcomes the poisoning issue while air feed operation by shifting the chemical equilibrium of the undesired carbonate ions toward hydroxide and in the presence of water at elevated temperatures, thus releasing from the electrolyte in situ during fuel cell operation. This contribution will highlight our recent developments in this area.
[1] Urquidi-Macdonald, M.; Sen, A.; Grimes, P.; Tewari, A.; Sambhy, V. NSF Report from Penn State. https://arxiv.org/pdf/physics/0504130
[2] Hibino, T.; Kobayashi, K., Journal of Materials Chemistry A
2013,
1 (24), 7019-7022
[3] Cerón, MR.; Lai, SZ.; Amiri, A.; Monte, M.; Katta, S.; Kelly, JC.; Worsley, MA.; Merrill, MD.; Kim, S.; Campbell, PG.; Journal of Membrane Science 2018, 567, 191-198