bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of the High Temperature PEM Membrane Electrode Assembly
Authors: Kerr Robert , García Héctor R. , Romero Maria T. , Terkelsen Carina , Hjuler Hans A. , Steenberg Thomas 
Published: February 2020

High temperature polymer electrolyte membrane (HT-PEM) fuel cells provide an attractive alternative to low temperature (LT) PEM fuel cells owing to several advantages that include a tolerance to carbon monoxide so that reformate may be used, simplified cooling systems and balance of plant, higher value waste heat and no need for humidification of reactants. PEMs derived from phosphoric acid-doped polybenzimidazoles (PBI) have so far generated the most interest for high temperature PEM fuel cell operation. However, in order to realize a commercially competitive product there are several challenges that remain regarding the performance, durability and cost – particularly the cost associated with the platinum-based electrodes.
This communication will provide details on some of the HT-PEM MEA performance targets most recently achieved by Danish Power Systems, namely;

MEA performances of >0.7 V cm-2 at 0.2 A cm-2 and >0.5 V at 0.8 A cm-2 using dry H2/Air.

MEA lifetime of 12000 h at 0.23 A cm-2 using dry H2/Air with a degradation rate of <10 µV h-1.

An integrated 5 kW stack/reformer system operating for 3000 h using methanol reformate as fuel.

The task of optimizing MEA performance is carried out using rotating disc electrode voltammetry and CO stripping/electrochemical surface area studies in order to improve electrode properties (porosity and phosphoric acid management). Investigations into MEA durability are conducted using post mortem analyses on MEAs tested under operating conditions. These studies are comprised of cross-sectional SEM imaging and X-ray diffraction to monitor catalyst layer/membrane degradation and catalyst particle growth, respectively. Studies using reformate have also led to promising results with an MEA performance of 0.58 V cm-2 at 0.385 A cm-2 with a degradation rate of 30 µV h-1 using wet H2 (30 mol%)/Air.
In addition to reaching performance benchmarks, a reduction in the standard deviation for MEA performance to <5% has been achieved through efforts aimed at improving the uniformity of the membrane and catalyst layer thicknesses.
Development of Next Generation Heavy Duty Bus Fuel Cells with Enhanced Durability
Authors: Kjeang Erik , Holdcroft Steven , Knights Shanna , Malek Kourosh , Djilali Ned , Eikerling Michael , Golnaraghi Farid , Wang Gary , Rajapakse Nimal , Wild Peter , Devaal Jake , Lauritzen Mike , Watson Mark , Rogers Erin 
Published: February 2020

The large-scale commercialization of durable and cost-competitive Polymer Electrolyte Fuel Cell (PEFC) technology for automotive applications still faces significant challenges. Fuel cell manufacturers need to develop low cost materials and fabrication approaches that surpass current levels of performance and durability. With funding from Ballard Power Systems and Automotive Partnership Canada, the present three-year project is dedicated to research and product development of next generation PEFC stack technology for transit buses [1]. The central objective is to advance the fundamental understanding of membrane degradation mechanisms and failure modes under drive cycles and conditions that are typical of heavy duty vehicle operation, and to leverage this knowledge to develop enhanced durability solutions.
The project involves a cohesive research team from Ballard Power Systems, Simon Fraser University, and University of Victoria, with complementary and multi-disciplinary expertise in fuel cell science and technology, materials design and fabrication, multi-scale modeling, system design and engineering, as well as system controls and diagnostics. A comprehensive experimental-theoretical research approach is pursued that ranges from fundamental theory to empirical analysis, with close university-industry collaboration. For validation purposes, the research benefits from extensive real-time field data and field operated material samples extracted from the Whistler, British Columbia fuel cell bus fleet. The results obtained to date have enabled substantial improvements in membrane stability under bus conditions (based on laboratory testing) and enhanced the ability to accurately predict the fuel cell stack lifetime over several years of on-road transit service. This understanding will guide the development of the next generation of heavy duty fuel cell modules that reduce both capital cost and operating costs of fuel cell buses, making them commercially competitive with diesel hybrid buses on a lifecycle basis.
References: [1] http://www.apc-hdfc.ca/
Hydrogen Fuel Cells for Small Unmanned Air Vehicles
Authors: Swider-Lyons Karen , Stroman Richard O'Neil , Gould Benjamin D. , Rodgers Joseph A. , Mackrell Joseph , Schuette MIchael , Page Gregory 
Published: February 2020

The Naval Research Laboratory has been researching the use of hydrogen fuel cells for propulsion of long-endurance unmanned air vehicles (UAVs) for military and civilian applications. The high electrical efficiency of polymer electrolyte fuel cells (PEFCs) in combination with the high energy content of hydrogen enable the long endurance flights. The systems also offer the numerous attractive attributes of electric power, including instant starting, ease of control, near-silent operation, rapid load response, and high quality electric power.
The progression of Ion Tiger flights will be discussed. Ion Tiger used a ~ 1 kg 550-W (0.75-horsepower) fuel cell system from Protonex Technology Corporation with 0.5 kg of compressed H2 in a 4-kg a carbon/aluminum pressure vessel to fly for 24 hours continuously in Nov 2009. The vehicle also carried a 5-lb payload. In April 2013, the Ion Tiger flew for 48-hours by using liquid hydrogen fuel in a new, NRL-developed, cryogenic fuel storage tank and delivery system. These 1-day and 2-day demonstrations prove that hydrogen fuel cells provides a clear path to long endurance electric flight: in comparison, the Ion Tiger would be able to fly for only 4 hours on the comparable amount of lithium batteries.
This talk will discuss the scientific challenges related to using PEFCs in UAVs. The most important criterion is weight, demanding a high power to weight fuel cell along with high efficiency to maximize the use of the on-board hydrogen. Therefore, high activity, efficient electrocatalysis is needed, along with components with few I2R losses. The system should ideally operate near 80 °C to minimize the need for heat rejection. We have also become cognizant of poisoning issues, specifically related to coolant leakage through carbon bipolar plates, and also issues related to airborne contaminants, such as SO2, and the NaCl in sea mist.
We are grateful for support from the Office of Naval Research.
La2NiO4 Ceramic Electrodes for Hydrogen Peroxide Electroreduction
Authors: Santos Diogo M.F. , Sousa Nuno , Sljukic Biljana , Sequeira Cesar A.C. , Figueiredo Filipe M 
Published: February 2020

Direct borohydride/peroxide fuel cells (DBPFCs) use sodium borohydride (NaBH4) as an anodic fuel and hydrogen peroxide (H2O2) as the oxidant. DBPFCs are superior to similar types of fuel cells in terms of their theoretical cell voltage and energy density. Additionally, the fact that both fuel and oxidant reactants are liquid at ambient temperature simplifies their storage, thermal management and internal processing [1]. For these reasons, DBPFCs can be promising alternatives as power sources for space, underwater, and specific terrestrial applications where oxygen is not available.
To develop the DBPFC, we are focused on finding low-cost, stable, durable, and efficient electrocatalytic materials for H2O2 reduction that can simultaneously inhibit its decomposition. H2O2 decomposition is known to proceed even on platinum, which is the most commonly used electrocatalyst. Recently, some perovskite-type oxides were found to have reasonable activity for H2O2 electroreduction in DBPFCs [2].
Here, La2NiO4 ceramic disks are prepared by mechanosynthesis and characterized by scanning electron microscopy and X-ray diffraction. The use of ceramic pellets as electrodes allows avoiding cross-contributions of carbon or nickel foam catalyst supports, thus preventing the influence of such effects in the evaluation of La2NiO4 activity.
Several electrochemical methods, namely cyclic voltammetry, chronoamperometry and chronopotentiometry, were used to investigate the electrodes activity for H2O2 reduction in alkaline media. These studies made possible determination of the reaction kinetic parameters as well as its coulombic efficiency. The effect of temperature on the calculated number of exchanged electrons and on the charge transfer coefficients was analyzed. Stability tests were also performed.
Then, a test laboratory DBPFC was assembled using a La2NiO4 cathode and main cell parameters (e.g., open circuit voltage, peak power density, cell voltage and current density at the peak) were evaluated for temperatures ranging from 25 to 65 ºC.
References

D.M.F. Santos, C.A.C. Sequeira, Sodium borohydride as a fuel for the future, Renew. Sustain. Energy Rev. 15 (2011) 3980.

D.M.F. Santos, T.F.B. Gomes, B. Sljukic, C.A.C. Sequeira, F.M.L. Figueiredo, Electrochemical study of perovskite cathodes for H2O2 reduction in direct borohydride fuel cells (in preparation).
Hybrid Electrolyte Membranes Based on Sulfonated Poly (arylene ether sulfone ketone) Multiblock Copolymer for PEMFC Operating at Elevated Temperatue under Low Humidity
Authors: Shanmugam Sangaraju , Lee Ki Bong , Ketpang Kriangsak , Lee SangCheol , Lee Dong Ha 
Published: February 2020

Abstract

Polymer electrolyte membrane fuel cells (PEMFCs) operated under low relative humidity (RH) have been received great attention due to simplifying thermal management and reducing the cost of the system. However, the state-of-the-art electrolyte membrane (Nafion), has several problems, such as high production cost, environmental incompatibility, and insufficient thermomechanical properties above 80 oC.[1] To overcome these problems, aromatic hydrocarbon polymers are considered promising alternatives, such as sulfonated poly arylene ether sulfone ketone (SPESK) multiblock membranes have been reported.[2]Nevertheless, SPESK membrane exhibits poor performance under low relative humidity (RH).
We have developed high proton conducting membranes based on modifying non-fluorinated aromatic ionomers using hygroscopic metal oxide and inorganic proton conductors. We have synthesized novel composite membrane using porous hygroscopic titanium dioxide nanotubes (TNTs) incorporated SPESK membrane. TNTs with average diameter of 90 nm were incorporated into SPESK solution so as to provide the proton migration pathway in SPESK membrane. Compared to pristine SPESK, SPESK-TNT delivered 2.4 times higher maximum power density at 80 oC under 30 % RH. The higher PEMFC performance under low RH was due to the hygroscopic property of TiO2which can retain water and due to the tubular morphology which facilitates the proton transport channel through membrane.
We also fabricated inorganic proton cluster modified graphene oxide SPESK composite membrane. The deposition of phosphotungstic acid (PW) on the modified graphene oxide sheet with positively charged functional group was carried out through an electrostatic interaction between PW and the modified graphene sheets to make heterogeneous system. The modified graphene oxide (mGO) was synthesized through a simple condensation reaction. A mixture of mGO and PW aqueous dispersion was stirred to fabricate PW-mGO. The physico-chemical characterization of inorganic cluster and the modified graphene oxide was confirmed by UV-visible, IR and cyclic voltammetry studies and these results revealed that that an alteration of the electronic structure of deposited cluster as a result of strong hybridization between the graphene oxide and PW [3].These SPESK composite membranes exhibited much higher proton conductivity at relatively low humidity than the pristine SPESK, and the composite membrane showed higher maximum power density PEMFC operated under 18 % RH than that of pristine membrane. The synthesis of composite aromatic membranes, conductivity and fuel cell performance at elevated temperature under low relative humidity will be discussed in this presentation.

References

1.S. Bose, et al., Prog. Poly. Sci.
36 (2011) 813.
2.B. Bae, et al., Angew. Chem. Int. Ed. 49(2010) 317.
3.Y. Kim, and S. Shanmugam, ACS Appl. Mat. Int.,5 (2013) 12197.
The Role of Lipid-Membrane in the Direct Electrochemistry of Human Liver-Microsomal Films
Authors: Krishnan Sadagopan , Walgama Charuksha , Nerimetla Rajasekhara , Schildkraut Deniz , Elman James F 
Published: February 2020

Cell membranes play a crucial role in molecule/ion transport, cell signaling, bioenergetics, interactions between biomolecules, and many other important biological processes. Due to these significant roles of lipid-membranes in life-processes, investigating the ion and charge-transport processes across them in vitro by designing biomimetic membranes has been an active research area. Lipid-membranes have been used widely to construct artificial photosynthetic systems and efficient electro- and photo-catalytic processes. Nevertheless, the potential of exploiting transport processes across lipid-bilayer membranes in developing robust modern biosensors, biocatalytic systems, and energy-conversion devices is challenging.
We provide here new insights on the direct electrochemical kinetics of micron-thick innate human liver-microsomal films containing embedded oxidoreductases and major drug metabolizing monooxygenase enzymes. Additional insights on the effect of electrode-materials in oxygen binding kinetics to the oxidoreductase reduced heme-proteins present within the HLM-film will also be presented. We were able to control the nominal HLM-film thickness by using different electrode-materials, and thus seem to have influenced the arrangement of redox proteins in the HLM-films. Our results suggest that one can directly use liver-microsomal films coated on appropriate electrodes for drug screening and biosensing applications without requiring purified monooxygenases and reductases, reconstituted assay systems, chemical/NADPH electron donors, and electrode modification procedures. Thus the cost and time of developing novel drug screening platform can be greatly minimized.

Acknowledgements. This work was supported by the Oklahoma State University.
The Protoelectric Potential Map (PPM): The Two-Dimensional Plot of Absolute Redox Potentials and Absolute pH Values
Authors: Radtke Valentin , Himmel Daniel , Pütz Katharina , Krossing Ingo 
Published: February 2020

We recently introduced a unified Brønsted acidity scale on the basis of the chemical potential of the proton in any medium allowing the comparison of pH values of different media and a precise definition of superacidic media. For this purpose we defined the reference state of maximum acidity as the standard chemical potential µ
abs°(H+, g) of the proton in the gas phase (ideal H+ gas at 1 bar and 298.15 K), which is arbitrarily set to 0 kJ mol–1. The acidity and hence the chemical potential of the gaseous proton H+(g) is lowered by the interaction with any type of a medium, i.e. complexation of H+ in the gas phase, solution, or in the solid state. In this way the defined absolute pH value pHabs depends in a simple manner on the absolute potential of the proton in the media of interest. [1]
Analogously to the definition of the pHabs value we define an absolute redox potential (peabs) scale on the basis of the absolute chemical potential of the electron with the ideal electron gas at 1 bar and 298.15 K as reference state (µ

abs°(e–, g) = 0 kJ mol–1). This scale establishes the possibility of direct comparison of the reduction power (which we term “reducity”) of any redox system in any medium. [2]
Above all, both scales are combined to the Protoelectric Potential Map (PPM, peabs vs. pHabs, see fig.) as the Hydrogen Evolution Reaction (HER) correlates the pH scale to the redox scale. [2] The thermodynamics of any redox, acid-base or combined system in any medium can be represented and related to any other. For example, the pH-dependency of a redox system can be easily read off by the slope of the line representing the redox system in the whole pH range of the solvent under consideration. Thermodynamic stabilities of solvents can be clearly displayed and even predictions of reactions become possible at a glance, please compare with K. Pütz who presents that silver is a non-noble metal in the acidic IL HmimBr at this conference.
Figure: The Protoelectric Potential Map (PPM).
[1] a) D. Himmel, S.K. Goll, I. Leito, I. Krossing, Angew. Chem., Int. Ed. Engl.
2010, 49, 6885-6888; b) VIP-Paper: D. Himmel, S.K. Goll, I. Leito, I. Krossing, Chem. Eur. J.
2011, 17, 5808 – 5826.
[2] V. Radtke, D. Himmel, K. Pütz, S. Goll, I. Krossing, Chem. Eur. J.,
2014, DOI: 10.1002/chem.201302473
An Rrde Investigation of Manganese Dioxide Anodic Electrodeposition
Authors: Donne Scott W , Burns Robert C , Gibson Andrew J 
Published: February 2020

Manganese dioxide is a prominent material in the literature surrounding metal oxide based electrochemical supercapacitors due to its low toxicity and cost, combined with its good pseudocapacitive behaviour [1]. It is important to understand how the deposition of MnO2 proceeds on different substrates and in different solution conditions when attempting to design thin films of MnO2for use in electrochemical capacitors.
In this presentation, evidence will be presented that shows MnO2 deposition from solutions containing MnSO4 proceeds by one mechanism on Pt, and another on MnO2. The preferred mechanism of growth varies with acidity. In relatively acidic solutions, 0.1 M H2SO4, an island growth regime is seen. In solutions of neutral pH, 0.1 M Na2SO4, behaviour corresponding to a very rapid spread of a thin coating is seen. In both cases, the deposition on Pt proceeds by a solution based [Mn(OH2)6]3+ disproportionation mechanism, whereas the deposition on MnO2proceeds by a solid state reaction through the Mn(III) species, MnOOH.
Shown in the figure below is an example of the kinetic current curves obtained from the disc of the RRDE. These curves show that as the potential is increased, the Pt surface is more rapidly covered by MnO2, with a smaller nucleation kinetic current seen, related to the smaller size of islands at coalescence. It can be seen that these curves decay to the same current value, related to the kinetically (chemical, not electrochemical) limited transition from MnOOH to MnO2.
[1] A. D. Cross, A. Morel, T. F. Hollenkamp, S.W. Donne, Journal of the Electrochemical Society,
158, A1160 – A 1165, 2011.
A New Picture of the Electrochemical Double Layer Based on Modern Continuum Thermodynamics
Authors: Landstorfer Manuel , Dreyer Wolfgang , Guhlke Clemens 
Published: February 2020

We will revise the widely used concept of inner- and outer Helmholtz planes in electrochemical double layers based on modern continuum thermodynamics. At the metal/electrolyte interface various layers of solvated ions form, namely the inner Helmholtz plane for specifically adsorbed and partially solvated ions, and the outer Helmholtz plane for completely solvated ions closest to the metal surface[1]. It is assumed that all the ionic charge is stored on the respective layer, and that they have a constant width. The potential drop would thus be linear between the inner and the outer Helmholtz layer, which motivates the model concept of a simple plate capacitor.
Based on our new continuum mechanical mixture theory for solvated ions[2] we provide new insights to this model conception. It turns out that neither the inner, nor the outer Helmholtz plane can be modeled as rigid planes which are supposed to behave like simple plate capacitors. The picture of the inner Helmholtz plane (IHP) we draw is based on a surface mixture theory, which incorporates partial solvation, and shows that there is actually no potential drop across the metal/IHP layer. The outer Helmholtz plane results from the saturation of solvated ions closest to the metal surface and grows with an increasing applied potential. Hence, in both cases the model concept of simple plate capacitors is doubtable.
Evidence of this picture comes from a remarkable agreement to single crystal experimental data regarding the computed differential capacity C(U)[3-4].
In consequence, the different types of layers in the space charge region are naturally incorporated in our new mixture theories and an explicit modeling or descriptionof the space charge layer is not necessary.
[1] D. M. Kolb, Angewandte Chemie, 2001, 113, 1198–1220.
[2] W. Dreyer, C. Guhlke, M. Landstorfer, Electrochemistry Communications, 2014, DOI: 10.1016/j.elecom.2014.03.015
[3] G. Valette, Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1981, 122, 285 – 297.
[4] G. Valette, Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1982, 138, 37 – 54.
Separation of Heavy Bivalent Metals Extracted by Electrodeposition Using a STEEL Substrate from Wastewater
Authors: Addi Yassine 
Published: February 2020

ABSTRACT
Heavy metals contaminated waste water sludge is classified as hazardous solid waste(1). For this reason it needs to be properly treated to prevent releasing heavy metals to the environment.
The sludge was treated in a batch reactor (2) by sulfuric acid to extract the contained heavy metals ( Cu; Cd; Ni and Zn).
The effects of sulfuric acid concentration and solid to liquid ratio on the heavy metal removal efficiencies were investigated. The experimental results showed that the total and individual heavy metal removal efficiencies increased with increasing sulfuric acid concentration, but decreased with increasing solid to liquid ratio.
For 5g/L solid to liquid ratio, more than 99,9% of heavy metals can be removed from the sludge by treating with 0,5 M sulfuric acid in 2h.
The separation, of metals extracted by sulfuric acid from the sludge, is carried out by plating on steel substrate (3).
The electrode position is performed in two different media: acid and basic media. A comparative study of the two plating media was studied.
References;
(1) B.Johnke, B.Wiebusch, Fuel Energy Abstract.38(1997)350
(2) M.A.Styllanou,D.Kollia,K.J.Haralambous,V.J.Inglezakis,K.G.Moustakas,M.D.Loizidou, Desalination215(2007)73-81
(3) Mortaga M.Abou-Krisha, Applied surface science 252(2005)1035-1048