bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improve Activity and Stability of Ni-Ce0.8Sm0.2O1.9 As the Anode of a Methanol Fuelled Solid Oxide Fuel Cell
Authors: Zhao Yicheng , Li Yongdan 
Published: February 2020

Solid oxide fuel cells (SOFCs) are electrochemical devices those convert chemical energy in fuels directly into electricity. Compared with H2, commercial hydrocarbon fuels can be safely stored and are more readily available, which could reduce the overall operation cost. Therefore, direct electrochemical oxidation of hydrocarbons into electricity using SOFCs is appealing. However, there are many operational problems those still need to be solved. The typical NiO-YSZ anode material has excellent catalytic properties for fuel oxidation and good electrical conductivity, while it experiences serious carbon deposition with hydrocarbons as fuels. Therefore, there is a need for developing new kinds of carbon resistant SOFC anode materials for the utilization of hydrocarbon fuels.
In this work, Mo is utilized to modify the Ni-Ce0.8Sm0.2O1.9 (SDC) anode. The NiO-MoO3-SDC anode materials are prepared by impregnation technique, which are reduced to SDC and Ni-Mo alloy phases in H2 atmosphere. SOFCs with Ni-Mo-SDC composite anodes are fabricated and tested with methanol as fuel. The addition of Mo into Ni–SDC anode effectively improves performance and stability of the single cell at 700 oC. The anode with a mole ratio of Mo to Ni of 0.03:1 (Ni-3Mo-SDC) exhibits the lowest polarization resistance. The cell with that anode and SDC-carbonate composite electrolyte exhibits a maximum power density of 680 mW cm-2 at 700 oC. The stability of the cell is enhanced with the increase of the content of Mo in the anode.
In order to further improve the cell performance and stability, rare earth elements (La, Pr and Sm) are introduced into Ni-3Mo-SDC. The effects of La, Pr and Sm addition on the catalytic activity for methanol pyrolysis and coking resistance of the Ni-3Mo-SDC anode are examined. The electrochemical performance of the SOFC is enhanced with introducing La and Sm into the anode. The cell with La addition in the anode shows a maximum power density of 765 mW cm-2 at 700 oC with methanol as fuel. The addition of La, Pr and Sm into Ni-3Mo-SDC anode improves the stability of the cell, which is mainly attributed to the decreased amount of carbon deposition with a high graphitization degree.
(Invited) Phosphoric Acid Migration in Fuel Cells
Authors: Büchi Felix N , Halter Jonathan , Eberhardt Sebastian H. , Schmidt Thomas J. 
Published: February 2020

In phosphoric acid (PAFC) and high-temperature polymer electrolyte fuel cells (HT-PEFC) concentrated phosphoric acid is used as the electrolyte. In PAFC the acid is imbibed in an inert silicon carbide matrix while in HT-PEFC polybenzimidazole (PBI) membranes are used. In PAFC, because there is no interaction between the matrix and the acid the phoshate anion has a finite transference number which “results in acid migration toward the anode of an operating cell and results in migration between cells” quote from [1]. In PBI based membranes the phosphoric acid is bound to the PBI and its mobility reduced, so it was expected that acid migration is suppressed. However, in past years it was shown that acid migration is also an issue in HT-PEFC and most probably a life time limiting process. As in PAFC, in HT-PEFC, strategies need to be developed to limit acid migration and thus improve durability. This requires fundamental work to better understand migration and the imbibition of the porous structures at the anode. Therefore the wetting behavior of the anode gas diffusion layers with phosphorc acid is characzterized in ex-situ and operando experiments by X-ray imaging.
Similarities and differences in acid management and it’s characterization in PAFC and HT-PEFC is discussed and the prospects for HT-PEFC in the large co-generation market for small (1 kW) systems is assessed.
[1] H.R. Kunz, ECS Transactions, 11, 1447-1460 (2007)
(Invited) Current Status on Ballard Fuel Cells and Future Catalyst Development
Authors: Ye Siyu , Banham Dustin , Yang Lijun , Knights Shanna 
Published: February 2020

Hydrogen and fuel cell technologies offer a pathway to enable the use of clean energy systems to improve air quality, enhance energy security, and stimulate the global economy. Due to the significant advances in fuel cell technology over the last 25 years, fuel cells have become competitive in certain markets. Ballard Power Systems Inc. is recognized as a world leader in proton exchange membrane (PEM) fuel cell development and commercialization. At the heart of each Ballard PEM fuel cell product is a stack of unit cells based on Ballard’s proprietary technology, for unsurpassed performance, durability and versatility. Ballard draws on intellectual property together with unmatched know-how in key areas, including fuel cell MEA/stack development and systems integration. Ballard’s fuel cell products deliver the required functionality at the right scale with optimum performance and low lifecycle costs. This presentation will provide an overview of current status of Ballard fuel cell development.
To enable wide-spread commercialization of fuel cells, particularly automotive applications, further cost reductions and durability improvements are still required. For longer term PEM fuel cell products, the catalyst is still a major cost factor due to the use of platinum group metals (PGMs). In addition to cost, these PGM catalysts have insufficient durability for certain long life applications, particularly at low catalyst loadings. Thus, the most significant remaining challenge for PEMFC catalysts will be to achieve excellent activity at low PGM loadings while also maintaining high durability/stability during operation. The advantages and possible limitations of various types of catalysts, such as Pt alloys (de-alloys), core-shell catalysts and shape-controlled nanocrystal catalysts will be assessed. This presentation will conclude with a discussion of potential future directions for PEMFC catalyst and catalyst layer research to help overcome the last remaining challenges of performance and durability and propel PEMFCs into the wider commercial market.
(Invited) The U.S. Department of Energy’s Energy Materials Network
Authors: Sarkar Reuben , Joost William , Miller Eric L. 
Published: February 2020

Affordable, reliable, high performance materials and manufacturing technologies are key for most transformational technology advancements, including those in critical domestic energy applications. However, many materials discoveries in the laboratory either never reach widespread market deployment or spend decades in the development cycle at a cost of many tens or hundreds of millions of dollars. In response, the U.S. Department of Energy (DOE) has established the Energy Materials Network (EMN) to accelerate the materials-to-market process by better integrating the stages from materials discovery through manufacturing. The EMN is a network of national lab-led consortia that support both industry- and government-led research (e.g. CRADAs and FOA awards) on specific energy-related material challenges. The EMN framework facilitates industry stakeholder engagement to ensure that the research is immediately relevant, with high-impact commercial potential. To date, EMN consortia have been set up in the seven technology areas of: light-weight materials for transportation; precious-metal-free catalysts for fuel cells; water-splitting materials for hydrogen production; advanced catalysts for biomass conversion; new materials and designs for photovoltaic modules; advanced solid-state hydrogen storage materials; and advanced caloric materials for refrigeration. This presentation will describe the vision of the EMN as an enduring national resource, and discuss recent technical accomplishments in the current network of EMN consortia.
(Invited) Lightmat: A U.S. Dept. of Energy, Energy Materails Network
Authors: Herling Darrell 
Published: February 2020

Accelerating advanced materials development, from discovery through deployment, has the potential to revolutionize whole industries and is critical for the United States to compete globally in manufacturing in the 21st century. However, today only a small fraction of materials innovations make it to widespread commercialization. The goal of the U.S. Department of Energy’s Energy Materials Network (EMN) is to dramatically decrease the time-to-market for advanced materials that are critical to manufacturing many clean energy technologies, enabling manufacturers of all sizes to develop and deliver innovative, made-in-America products to the world market.
The Lightweight Materials National Laboratory Consortium, or LightMAT, is one of, and the first established, node in the EMN, and is comprised of ten national laboratories with technical capabilities highly relevant to lightweight materials development and utilization. LightMAT provides straightforward access to resources and capabilities in this network via a single point of contact and works to match industry research teams with expertise and equipment found only at national laboratories. This presentation will describe some of the unique technical capabilities available through the LightMAT network and how these will be applied to developing materials technologies for future low-carbon energy systems.
Electrochemically Initiated Formation of Sulfonyl Radicals: Synthesis of Oxindoles Via Difunctionalization of Acrylamides Mediated By Bromide Ion
Authors: Zeng Chengchu , Jiang Yangye 
Published: February 2020

An efficient electrochemical approach for the synthesis of oxindoles has been developed from electrolysis of a mixture of sodium sulfinate and acrylamide. The chemistry avoids the utilization of additional conducting salt and proceeds in a simple undivided cell employing catalytic amount of NH4Br (10 mmol %) as a redox catalyst. The protocol is practical that is proved by the one-pot, two-step procedure and scaled-up experiments. Mechanical studies reveal that the electrochemical approach involves the formation of sulfonyl radicals via homolytic cleavage of the in-situ generated sulfonyl bromide.
Scheme 1. Oxidative radical coupling for the synthesis of oxindoles

Figure 1
(Keynote) The Nature of the Interaction Between Electrogenerated Anions and Tetraalkylammonium Cations
Authors: Fry Albert Joseph 
Published: February 2020

A series of reports from this laboratory have described computational studies defining the first general binding motif yet discovered for ion pairing in conventional electrochemical media (1-4). These studies have shown that tetraalkylammonium cations interact in identical fashion with a variety of organic and inorganic electron donor species. For example, the structures (see image) generated by interaction between tetrabutylammonium cation and nitrobenzene anion radical, dianion, and even neutral nitrobenzene ,are identical. Remarkably similar structures have been found without exception for more than one hundred other species formed by interaction between tetralkylammonium cations where the alkyl group ranges from ethyl through heptyl and electron donors of diverse structural type (polycyclic aromatic hydrocarbon dianions, substituted benzaldehydes, nitrosobenzenes, and even inorganic anions).

The uniformity of binding between over a broad range of cationic and anionic structures in these many species is remarkable. Surely electrostatic attractions are important. Yet, in light of the high specificity of structure exhibited by these ion pairs and related species, one may well inquire into the reasons why this is so. Is the explanation simply electrostatic attraction between cations and anions? We will show evidence instead that formation of these structures involves a complex set of phenomena including electrostatics (of course) but also induced charges on each component and electron transfer between the two.

References

Fry, A. J. Tetrahedron
2006, 62, 6558.

Fry, A. J. J. Org. Chem.
2013, 78, 2111.

Fry, A. J. J. Org. Chem.
2013, 78, 5476.

Fry, A. J. J. Org. Chem.
2015, 80, 3758.

Figure 1
Electrosynthesis of Linear PEDOT Fibers By Means of Bipolar Electrochemistry
Authors: Inagi Shinsuke , Ohira Masato , Koizumi Yuki , Nishiyama Hiroki , Tomita Ikuyoshi 
Published: February 2020

Recently we reported the electropolymerization of 3,4-ethylenedioxythiophene (EDOT) and its derivatives on a bipolar electrode (BPE) with the sacrificial reduction of benzoquinone (BQ), and found that poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives propagated as a dendritic fiber form (φ = ca. 5 μm) from the ends of Au wires used as BPEs parallel to an external electric field.1

In this study, we demonstrated that the AC-bipolar electopolymerization of EDOT in a micro-space produced the PEDOT fibers with one-dimensional morphology.2 In this situation, the micro-space around the BPEs and generated PEDOT fibers was effective to limit the further access of EDOT monomer from the side of the fibers but allowed it at the terminal of the fibers, which led to the formation of linear PEDOT fibers. This method was found to be useful to connect BPE wires with linear PEDOT fibers, in which the growing direction could be controlled by the external electric field, in a better manner to the previous dendritic growth of PEDOT fibers. The rapid and selective wiring of conductors with organic microfibers would be of potential interest in the application for organic devices.
References
1. Y. Koizumi, N. Shida, M. Ohira, H. Nishiyama, I. Tomita, S. Inagi, Nat. Commun.
2016, 7, 10404.
2. M. Ohira, Y. Koizumi, H. Nishiyama, I. Tomita, S. Inagi, Polym. J. in press.

Figure 1
Impedance of Mediated Electrochemical Processes at Microelectrodes
Authors: Polczynski Piotr , Jurczakowski Rafal Robert 
Published: February 2020

Impedance spectroscopy, unlike any other electrochemical method, can provide a full insight into the mechanism and kinetics of electrode processes. However, the interpretation of impedance spectra is possible only for systems having a meaningful mathematical description leading to a proper equivalent circuit.
Recently, we have provided, for the first time, an exact analytical solution in linear diffusion regime for impedance of catalytic processes involving redox mediators [1]. In this process the electrochemical step (E) is followed by a homogeneous chemical reaction regenerating depolarizer (C’). In such systems various electroinactive and quite inert molecules can be catalytically oxidized or reduced by means of redox mediators that carry electrons from or to the electrode surface. Introduced model obtained for general case provide a powerful research tool that can be used in studies of many important catalytic processes. However, in many cases microelectrodes are used and spherical diffusion needs to be taken into account.
In this work, we present an analytical solution for faradaic impedance of the catalytic EC’ processes in spherical diffusion geometry. We provide the range of electrode radius, for which spherical model should be applied. We deliver an equivalent circuit together with potential dependence of all impedance parameters, which allows to rapid and precise determination of all kinetic and thermodynamic parameters of EC’ type reactions on microelectrodes. Similarly as for the solution in linear geometry the resistance of the charge transfer, R
ct tends to a constant value at high overpotentials.
The applicability of the model in characterization of the catalytic processes was confirmed experimentally. It has been shown that all key parameters of catalytic systems may be readily obtained even from a single impedance spectrum.
References:
[1] R. Jurczakowski, P. Połczyński, J. Phys. Chem. 118 (2014) 7980–7988
(Invited) Impedance Characterization of High-Temperature Spinned Fiber Ceramic Materials
Authors: Vanýsek Petr , Novák Vitězslav , Částková Klára , Chladil Ladislav 
Published: February 2020

Materials based on cubic ZrO2 stabilized with Y2O3 have good ionic conductivity at higher temperatures, which makes them suitable or promising candidates for use as a membrane in the solid oxide fuel cells (SOFC). The zirconia materials are mainly used as a compact ion conductive membrane, allowing the separation of the positive and negative electrodes while allowing ionic conduction via the oxygen ion. Another possible use in SOFC consists in the idea of creating a highly porous structure coated with a suitable catalyst (e.g., Ni) for the negative electrode. This would lead to a rapid increase in the active surface of the electrode and thereby increase the nominal current density of the fuel cell. The fibrous structure and its large porosity, while ionically bonding, appear to be very suitable for this purpose.
The methods of forming fibers in our laboratory are both the force spinning and electrospinning. From the spinned nanofibrous materials we prepared disc samples (pellets) with opposite flat sides coated with a conductive platinum paste and wee annealed. The prepared samples were contacted using platinum mesh electrodes (a two-electrode connection) to the heated chamber of instrument ProboStat (Dept. of Chemistry, University of Oslo). The whole probe device shrouded in ceramic tube was inserted into a tubular furnace. The sample was held at different temperatures and the impedance spectroscopy data were obtained for a series of temperatures. From this the total impedance of the system, as a function of temperature, was collected. A relative simple equivalent circuit was used to fit the data end extract mostly the conductivity of the sample at each given temperature. Impedance was collected using spectrometer Solartron 1260 at suitable temperature steps (usually 25 ° C) at AC amplitude 100 mV. The equivalent circuit fit was done using ZView (Scribner Associates). Fig. 1 shows an example of impedance plot compared for a bulk (nonfibrous) substrate and one, with prepared from the fibrous material.
The conductivity of ceramic materials is a thermally activated process, and therefore depends on temperature. Thermal conductivity changes are often described using the Arrhenius. In this case, the dependence of the logarithmic conductivity changes upon change of the inverse of the absolute temperature is linear and from the slope of the Arrhenius plot one can calculated the activation energy of the process (Fig. 2). From the figure it is apparent that the bulk and the fibrous material the activation energies are essentially identical, while the actual conductivities are significantly different for each; expectedly lower for the fibrous substrate.

Figure 1
High Performance Bioelectrocatalytic Interconversion Between Formate and Carbon Dioxide
Authors: Kano Kenji , Sakai Kento , Kitazumi Yuki , Shirai Osamu 
Published: February 2020

An interconversion of HCOO-/CO2 is one of essential requirements for carbon-based sustainable energy economy. However, when CO2 is reduced and HCOO- is oxidized directly on electrodes, carbon monoxide is generated and quite high overpotential is required. One of the most promising strategies for solving these issues is the utilization of enzymes as catalysts. Enzymes allow the system to function in a specific biological reaction under mild conditions. The electro-enzymatic devices can be used as energy conversion system such as HCOO-/O2 biofuel cells and an efficient bioelectrochemical system of the CO2 reduction.
We focused on the catalytic properties of tungsten-containing formate dehydrogenase (FoDH1; EC 1.2.1.2) from Methylobacterium extorquens AM1 to construct a bioelectrochemical interconversion system of HCOO-/CO2. FoDH1 is a heterodimeric soluble enzyme and catalyzes the oxidation of HCOO- to CO2 in coupled reduction of NAD+ to NADH. In this study, we have found that FoDH1 catalyzes both of the HCOO- oxidation and the HCO3
- reduction with several artificial redox partners (mediators). The bi-molecular reaction rate constants between FoDH1 and mediators and show a linear free energy relationship. The reversible reaction between HCOO- and CO2 through FoDH1 has been realized on cyclic voltammetry by using methyl viologen (MV) as a mediator and by adjusting pH from the thermodynamic viewpoint. The steady-state voltammograms with two-way bioelectrocatalytic properties are interpreted on a simple model by considering the solution equilibrium. Furthermore, we have constructed a light driven HCOO- production system using a spinach thylakoid membrane, MV, and FoDH1.
When the interconversion between HCOO- and CO2 is applied to the construction of efficient bioelectrochemical devices, a large current density should be realized at potentials close to the formal potential of the HCOO-/CO2 couple (E°'CO2). We show a great possibility of MET-type bioelectrocatalysis in the HCOO- oxidation and the CO2 reduction at high current densities and low overpotentials. For the HCOO- oxidation, a high limiting current density (j
lim) of about 24 mA cm-
2 was realized with a half wave potential (E
1/2) of only 0.12 V more positive than E°'CO2 at 30 °C in the presence of MV2+ as a mediator. When a viologen-functionalized polymer was co-immobilized with FoDH1 on the porous electrode, j
lim of about 30 mA cm-
2 was attained at 60 °C with E
1/2 = E°'CO2 + 0.13 V. On the other hand, the CO2 reduction was also realized at j
lim of about 15 mA cm-
2 with E
1/2 = E°'CO2 – 0.04 V at pH 6.6 and at 60 °C in the presence of MV. This is the first report of the enzyme-based bioelectrocatalytic CO2 reduction at such low overpotential and a high j
lim.
The present results are very useful to construct an effective bioelectrochemical reaction for the CO2 reduction and HCOO-/O2 biofuel cells as effective energy conversion systems.