bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Devices Based on Solid Acid Electrolytes for Conversion of Methane Derivatives
Authors: Wilson David Leon , Papandrew Alex , Zawodzinski Thomas A. 
Published: February 2020

A boom in natural gas production in the United States presents opportunities for economically effective use of methane-derived molecules. In contrast with methane gas, derivatives may exhibit advantages in volumetric energy density, ease of transport and versatility. Electrochemical conversion of these species to electricity and other fuels is desirable, but depending on the system in question, catalyst stability, activity, and impurity intolerance, or alternately, the cost and durability of the electrolyte may be impediments to adoption
The solid-state proton conductor cesium dihydrogen phosphate (CsH2PO4 or CDP) has shown potential in electrochemical devices operating on fuels such as reformed NG or methanol. CDP undergoes a solid-solid phase transition at 228 °C and an associated increase in proton conductivity of more than three orders of magnitude (8.5 x 10-5 S cm-1 at 223 °C to 2.5 x 10-2 S cm-1 at 250 °C). These systems have been shown to tolerate reformate streams in H2-air cells containing CO, H2S, NH3, CH3OH, C3H8 and CH4 of 20%, 100ppm, 100 ppm, 5%, 3% and 5% respectively, retaining 90-95% of pure H2 performance1. Solid acid fuel cells operated using methanol and an integrated steam reformer have also shown similar results2. Recently, we showed that this material can also be used in an electrochemical hydrogen separation system using similar reformate streams3.
In the majority of these earlier studies, platinum was used as the catalyst for both the hydrogen reduction and oxidation reactions. We have also demonstrated that unsupported nickel is an effective hydrogen evolution catalyst in solid acid hydrogen pump devices4. Here, we have synthesized a suite of carbon-supported non-platinum catalysts (Pt, Pd, Ru, Ni and Cu) for implementation in electrodes. We evaluate these materials as hydrogen oxidation and evolution catalysts in CDP-based devices for electricity and fuel production from the methane derivatives methanol and dimethyl ether.
This work is supported by the National Science Foundation through TN-SCORE (EPS-1004083).
References

1 C. R. I. Chisholm et al., Electrochem. Soc. Interface, 18, 53–59 (2009).

2 T. Uda, D. a. Boysen, C. R. I. Chisholm, and S. M. Haile, Electrochem. Solid-State Lett., 9, A261 (2006).

3 A. B. Papandrew et al., J. Electrochem. Soc., 161, F679–F685 (2014).

4 A. B. Papandrew, T.A. Zawodzinski Jr., J. Power Sources 245 (2014) 171.

Figure 1
On the Hydration of P2-Layered Sodium-Ion Cathode Materials in Aqueous Battery Applications
Authors: Frankforter Kevin Jerome , Anderson Marc Arlen , Tejedor M. Isabel 
Published: February 2020

The high-performance seen in today’s lithium-ion and sodium-ion batteries is enabled by the use of organic alkyl-carbonate electrolytes mixtures which demonstrate high electrochemical stability. However, the use of these organic solvents has led to significant challenges related to their safety/flammability, in addition to stringent processing requirements during manufacturing to avoid contamination of the electrolyte with water. This has led to interest in utilizing lithium-ion and sodium-ion intercalation electrode material with aqueous-based electrolytes.
Recent work on the development of high-performance sodium-ion cathode materials has identified layered transition-metal oxides synthesized with a P2 stacking sequence demonstrate both high capacity and high capacity retention, which makes this class of intercalation compounds promising for use in battery applications.
Our work focuses on the consequences of utilizing P2-layered oxides in aqueous electrolytes; in particular, the vulnerability of these layered materials to hydration, in which water is incorporated into the layered structure. This phenomenon is not dissimilar to the weathering of many naturally occurring layered minerals such as Mica and Vermiculite. P2 compounds of multiple compositions will be studied using a variety of techniques including cycling results, x-ray diffraction, and thermo-gravimetric analysis in order to identify the onset of material hydration as well as the ramification of this phenomenon for aqueous battery applications.
(Invited) Metallated and Metal-Free Molecular Materials for Light/Electrical Energy Conversion
Authors: Wong Wai-Yeung 
Published: February 2020

Metallated and metal-free molecules have become a field of intense activities in the optoelectronic research. They hold great promise as versatile functional materials for use in energy interconversions. These include systems where light is transformed into electricity and vice versa. This lecture highlights the recent progress in the advances of numerous functional metal-organic and organic molecules with tunable photofunctional and electronic traits. Focus is placed on examining their potential as efficient emitters in light-emitting applications and semiconductors in photovoltaic cells (both organic and dye-sensitized solar cells) for solar power generation. The strategies based on structural modifications of the organic groups to tune the emission and photovoltaic properties of these materials will be presented and discussed.
Examing Proton Coupled Electron Transfer, Oxygen Reduction, and Anion Diffusion Using a Hybrid Bilayer Membrane
Authors: Gewirth Andrew A. , Tse Edmund C. M. , Barile Christopher J. 
Published: February 2020

In this talk, we report on our work synthesizing and characterizing Cu-based catalysts for the oxygen reduction reaction. In particular we prepared the first synthetic Cu O2 reduction catalyst that forms a self-assembled monolayer (SAM) on Au surfaces. We embeded this Cu catalyst inside a hybrid bilayer membrane (HBM) by depositing a monolayer of lipid on the SAM. By incorporating an alkyl phosphate in the lipid layer, we develop the first HBM containing a reversible switch that gates proton transport to a molecular oxygen reduction reaction (ORR) catalyst. We envision that this strategy can give unique mechanistic insight not only to the ORR, but to all proton-coupled electron transfer (PCET) reactions.
We also use the hybrid bilayer membrane as an electrochemical platform to study anion diffusion through a lipid monolayer. We first append lipid on a self-assembled monolayer that contains a covalently-bound Cu(I)/(II) redox center. We then perform cyclic voltammetry using different anions in the bulk solution and extract thermodynamic and kinetic information about anion transport. We analyze the results using linear combinations of fundamental chemical trends, and determine that anion transport quantitatively correlates to polarity and basicity, a relationship we formalize as the lipid permeability parameter. In addition, we discuss how our findings can be interpreted according to the two leading mechanisms describing ion permeability through lipids. Our results demonstrate that anion transport in a HBM is best described by the solubility-diffusion mechanism, not the pore mechanism.
Indium Tin Oxide and Silicon Nanocrystal Nanocomposite Grown By Aerosol Assisted Chemical Vapour Deposition
Authors: O'Brien S , Linehan K , Doyle H , Kingsley A , Ashfield C , Frank B , Xie L , Leifer K , Thony P , Perraud S , Pemble M E , Povey I. M 
Published: February 2020

Nanocomposite films were successfully grown by aerosol-assisted chemical vapour deposition (CVD) in a single deposition step using a mixture of Indium Tin neodecanoate and ligand stabilised silicon nanocrystals. Samples were analysed by HRTEM and silicon nanocrystals with a density of 1.2 × 1012 cm-2 were observed. From the reconstructed 3D tomogram, the averaged distance between the nearest nanoparticles is 8.3 nm and the 3D density of nanoparticles is 1.6 × 1018 cm-3. An animation of the 3D reconstruction is supplied in the supporting information. These data show the versatility of aerosol assisted CVD in achieving a nanocomposite with such a density of silicon nanocrystals, of carefully controlled size and shape, within a polycrystalline host matrix. Therefore, meeting the density and size distribution requirements of particle inclusion in active nanocomposites for photovoltaic structures
Structural Basis for Heme Transport By Hmut in Corynebacterium Glutamicum
Authors: Aono Shigetoshi 
Published: February 2020

Heme can be used as an iron source by some pathogenic bacteria, which have the heme acquisition system(s) to uptake heme. The typical heme acquisition system comprises several heme-binding proteins and an ABC transporter. The ABC heme transporter, HmuT-HmuUV is conserved in Gram-positive and Gram-negative bacteria. In this heme transporter system, HmuT, HmuU, and HmuV act as a substrate (heme)-binding protein, a heme permease, and an ATP-binding protein, respectively.
In this study, the crystal structure of the heme-binding protein HmuT (CgHmuT) from Gram-positive bacterium Corynebacterium glutamicum will be reported at 1.4 Å resolution. The overall structure of CgHmuT reveals a bi-lobed topology formed by an N- and C-terminal domain. A heme molecule coordinated by His141 and Tyr242 is bound in a cleft between the N- and C-terminal domains. Though the global fold of CgHmuT is similar to that of HmuT from Yersinia pestis (YpHmuT), the coordination structure of the heme is different from each other. While two heme molecules are bound to YpHmuT, CgHmuT binds a single heme molecule with His141 and Tyr242 as the axial ligands.
Intriguingly, CgHmuT binds a heme with two different orientations. Though the previously reported heme-binding proteins have the interaction between proteins and heme propionate groups in addition to axial ligation to iron, such interactions with heme propionates are absent in CgHmuT. The presence of two different conformations in CgHmuT might be due to a lack of specific interactions between the heme and protein except for the axial ligations.
EPR spectroscopy reveals the heme in CgHmuT is a mixture of high-spin and low-spin states, indicating one of the axial ligand of the heme is in equilibrium between the ligated and unligated states. EPR spectra of wild-type, H141A-, and Y242A-CgHmuT suggest His141 will be reversibly dissociated/associated from/to the heme. The equilibrium between the six- and five-coordinate states in CgHmuT would be responsible for the regulation of heme-binding affinity to control the heme transport reaction between CgHmuT and HmuUV.
The crystal structures of H141A and Y242A variants have also been determined in this study. Iwill discuss the molecular mechanism of heme recognition and heme transport by CgHmuT based on these structures.
Formation of Hydrogen-Bonded Supramolecular Assemblies Based on Functionalized Saddle-Distorted Porphyrins
Authors: Kojima Takahiko , Kajii Hiroki , Sankar Muniappan , Ishizuka Tomoya , Kotani Hiroaki , Yamada Yusuke , Fukuzumi S. 
Published: February 2020

Supramolecular assemblies consisting of porphyrins have been intensively investigated in the light of promising photo-functionality including photoinduced electron transfer, photo-conducting materials, dye-sensitized solar cells, and guest inclusion toward the emergence of novel functions on the basis of unique spatial host-guest arrangements and interactions.
Along this line, we have developed a series of supramolecular assemblies using the diprotonated form of saddle-distorted dodecaphenylporphyrin (H2DPP) through intermolecular π-π interaction, such as Porphyrin Nanochannels, which include electron-donating guest molecules.1 In this presentation, we present formation and characterization of supramolecular assemblies based on H2DPP derivatives having hydrogen-bonding functional groups and their metal complexes.
Introduction of carboxyl groups or hydroxyl groups to the meso-phenyl groups of H2DPP as hydrogen-bonding sites allows us to construct robust and well-organized supramolecular assemblies. A diprotonated tetracarboxyl-DPP derivative (1, Fig. 1a), for example, formed two-dimensional hydrogen-bonding networks (Fig. 1b) to form a porphyrin nanochannel structure, which were reminiscent of that formed by [H4DPP2+]Cl2 and was persistent up to 150°C, in contrast to that of [H4DPP2+]Cl2.2 To expand the size of the nanochannels, we also introduced 4-carboxylphenyl groups at the 4-positions of the meso-phenyl groups of H4DPP2+.
A Zn(II) complex of H2DPP derivatives having hydroxyl groups at the 4-positions of the meso-phenyl groups (2) was prepared to form a dimer bridged by 4,4’-bypyridine.3 The dimer was revealed to form intermolecular hydrogen-bonding network among the hydroxyl groups in the crystal.
In addition to the crystal structures, we will also mention adsorption of gaseous molecules such as N2 and CO2 with porous supramolecular assemblies of functionalized H2DPP derivatives in the solid state.
References

(a) R. Harada et al., Chem. Commun.
2005, 716. (b) T. Kojima et al., Chem.–Eur. J.
2007, 13, 8714. (c) T. Nakanishi et al., Chem. Mater.
2008, 21, 7492. (d) S. Fukuzumi et al., Coord. Chem. Rev.
2012, 256, 2488.

T. Ishizuka et al.
Chem. Commun.
2012, 48, 6481.

T. Ishizuka et al.
Dalton Trans.
2013, 42, 16073.

Figure 1
Synthesis and Electrochemical Properties of Phthalocyanines Bearing Fc(CH2)ns- and Dodecyl Substituents in Non-Peripheral Positions
Authors: Lewtak Jan P , Swarts Jannie C 
Published: February 2020

Phthalocyanines and their metal complexes1 gain constant attention due to their chemical, thermal and photochemical stability as well as numerous applications including catalysis, as ink-jet printing components, photosensitizers for photodynamic therapy of cancer, memory devices and liquid crystals. The introduction of a ferrocenyl moiety to the core of phthalocyanine macrocycle imparts a new redox active centre in addition to four existing macrocyclic centres. Non-peripherally substituted long alkyl chains contribute to the solubility of the macrocycle, assist in studying catalytic properties and, depending on the type of substituent, convey the possibility of possessing liquid crystal properties.
Here we present the synthesis of above compounds and the results of their electrochemical investigation. Our particular interest lies in the dependence of ferrocenyl redox properties on the electron withdrawing properties of phthalonitrile. It was found to be a function of the linker atom (S) or lack of thereof as well as the chain length (expressed as n above). The redox properties were probed utilising glassy carbon working electrode as well as gold electrode to immobilize sulphide species. Dodecyl chains attached to the core of macrocycle proved increasing solubility of compounds in organic solvents2 and also led to liquid crystalline properties.
References
1. E. Fourie, J. C. Swarts, I. Chambrier, M. J. Cook, Dalton Trans., 1145-1154 (2009).
2. J. C. Swarts, E. H. G. Langner, N. Krokeide-Hove, M. J. Cook, J. Mater. Chem., 11, 434-443 (2001).

Figure 1
Photoelectrochemical Oxygen Reduction Reaction Using Phthalocyanines
Authors: Ishii Kazuyuki 
Published: February 2020

The oxygen reduction reaction (ORR) has attracted broad interest not only with respect to biological processes, such as cellular respiration, but also in terms of practical energy conversion, i.e. cathodic reactions in fuel cells. Because the use of light energy is one of the promising alternatives to platinum that is utilized as an efficient catalyst for the ORR, we have investigated the photoelectrochemical ORR using various phthalocyanines (Pcs, Figure 1). The cathodic current corresponding to the ORR significantly increases upon visible light irradiation of the thin film consisting of Pc and the polyvinylidene difluoride (PVDF) polymer coated onto an ITO electrode (Figure 2). Although a previous study suggests that the high photocurrent may originate from the initial electron transfer between the photoexcited Pc and O2 (Pc* + O2 → Pc+ + O2
-) followed by the hole-transport between Pcs, herein we propose a new mechanism that can explain the efficient photoelectrochemical ORR in the Pc/PVDF thin film. The dependence on the reduction potential of Pcs indicates that the electrochemical reduction of the photoexcited Pc is an initial process. Subsequently, the electron transfer from Pc- to O2, i.e. Pc- + O2 → Pc + O2
-, occurs. Based on the comparison between the ZnPc and MgPc derivatives whose excited triplet quantum yields are different, the high photocurrent mainly originates from the electrochemical reduction of Pcs in the lowest excited singlet state, while the reaction via the lowest excited triplet state contributes to an increase in photocurrent only when the electrode potential is below +0.2 V. This study will be useful for developing catalysts for the photoelectrochemical ORR.
(1) D. Schlettwein, M. Kaneko, A. Yamada, D. Wöhrle, N. I. Jaeger, J. Phys. Chem.
1991, 95, 1748-1755.
(2) D. Schlettwein, N. I. Jaeger, J. Phys. Chem.
1993, 97, 3333-3337.

Figure 1
Refractory Metal Coatings on High Creep Strength Steel for Oxyfuel Coal Combustion
Authors: Suni Ian Ivar , Falola Daniel , Muralidas Pooja , Wiltowski Tomasz 
Published: February 2020

Oxyfuel coal combustion, where coal is burned in oxygen instead of air, offers the potential for simplified CO2 sequestration, since the flue contains little N2 and is mainly CO2. However, the widespread use of flue gas recycling to dilute the pure oxygen feed stream exacerbates corrosion problems in the furnace and boiler tubes by increasing the concentrations of SO2, SO3, HCl, and H2O. In addition, the dew point temperature is raised, making condensation of H2O, H2SO4 and H2SO3more likely during downtime.
P91 steel, which contains ~8.4% Cr, 0.9% Mo and 2.2% V, is are widely utilized for high temperature applications in the power industry due to its increased creep strength. However, Cr-containing steels are susceptible to failure in H2O-containing oxidizing environments due to formation and volatilization of compounds such as CrO2(OH)2. We report the formation of Ti and Zr diffusion coatings atop high creep strength steels to improve their corrosion resistance. Ti coatings 10-30 µm thick can be formed on P91 steel by pack cementation at 1000°C in flowing Ar. Similarly, Zr coatings 10-30 µm thick can be formed by pack cementation at 1080°C.
The composition as a function of position for both Ti and Zr diffusion coatings is studied as a function of position by scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDX). This demonstrates formation of an inter-diffusion zone, with no sharp interface exists between coating and substrate, which may help limit delamination. Results will also presented for thermogravimetric analysis (TGA) of both Ti and Zr coatings on P91 steel in gas mixtures that contains 5% N2, 70% CO2, 2% CO, 0.3% SO2, 21.7% H2O, 1% O2, and trace levels of HCl.
Phthalocyanine Based Advanced Corrosion Resistant Coatings By LbL Technique
Authors: Yakut Yonca , Cebeci Fevzi Çakmak 
Published: February 2020

Corrosion on metallic surfaces has been an ongoing and serious problem in the aeronautical industry. Advanced materials used for anticorrosive purposes contain heavy metals that damage the nature. Therefore, there is a need for improvement on environmental friendly coatings especially for the aeronautical industry.
In this study, anticorrosive thin film coatings are fabricated in order to prevent the metallic surfaces from the corrosive effect of singlet oxygen. Layer-by-layer (LbL) method is preferred as an alternative to literature. By the help of LbL it is possible to control the thickness and stability of the films. Oppositely charged materials (e.g polyelectrolytes) cover the surface of the substrate (glass, metal, Si-plate) by electrostatic attraction[1, 2]. Dip and spray LbL techniques are applied to obtain smooth and homogenous layers of polyelectrolytes and phthalocyanines[3]. The phthalocyanines have been embedded between the bilayers or tetralayers of thin multilayer films to get rid of corrosive effects of the highly reactive singlet oxygen by utilizing singlet oxygen reducing capability of these metal-centered compounds[4].
Electrochemical corrosion characterizations are performed to measure the corrosion resistance of the thin films. For this purpose, potentiodynamic polarization, Tafel, impedance and corrosion chamber tests are studied. Mechanical integrity of the films plays a great significance for demanding applications. Hardness/elastic modulus properties are analyzed to test the resistance of films.

References:

1. Decher, G., Hong, J. D., Schmitt, J., Buildup of Ultrathin Multilayer Films by a Self-Assembly Process .3. Consecutively Alternating Adsorption of Anionic and Cationic Polyelectrolytes on Charged Surfaces. Thin Solid Films, (1992). 210(1-2)(831-5).

2. Decher, G., Fuzzy Nanoassemblies: Toward Layered Polymeric Multicomposites. Science, 1997. 277(5330): p. 1232-1237.
3. El Harakeh, M., et al., Charge separation and photocurrent polarity-switching at CdS quantum dots assembly in polyelectrolyte interfaced with hole scavengers. Phys Chem Chem Phys, 2009. 11(28): p. 5962-73.
4. Dumoulin, F., et al., Synthetic pathways to water-soluble phthalocyanines and close analogs. Coordination Chemistry Reviews, 2010. 254(23-24): p. 2792-2847.
Electrochemical Impedance Spectroscopy Investigations of Stainless Steels in Presence of Corrosion Inhibitors
Authors: Ribeiro Josimar , Moreira Roberta Rossi , Soares Thiago Freitas 
Published: February 2020

The behavior of corrosion and corrosion inhibition of AISI 1010 carbon steel, AISI 316 stainless steel and UNS S31803 duplex steel was studied in sodium chloride solution (3.0 wt. %), in the absence and presence of benzimidazole and imidazole corrosion inhibitors. The chemical and morphological characterization of steels were performed using the techniques such as optical emission spectrometry, optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Electrochemical analysis were performed through the techniques of potentiodynamic polarization and electrochemical impedance spectroscopy. Metallographic, SEM and EDX analysis allowed to identify certain regions and elements present in the steel which provide corrosion occurring, such as inclusions.The electrochemical impedance results showed that the benzimidazole inhibition efficiencies were approximately 52%, 73% and 71%, respectively, for AISI 1010, AISI 316 and UNS S31803 steels. In the case of the imidazole was obtained efficiencies of about 96% for the AISI 1010 and AISI 316 steels and 85% for the UNS S31803 steel. Weight loss tests showed that for AISI 1010 steel, both benzimidazole and imidazole inhibit corrosion, and reduced the corrosion about 17% and 24%, respectively. In the analysis of the polarization curves in studies with seawater, it was observed that the inhibitors were lower efficient than in the middle chloride solution. The benzimidazole showed efficiencies of about 14%, 50% and 33% for AISI 1010, AISI 316 and UNS S31803 steels, respectively. In the case of Imidazole, it was observed that the inhibition efficiency of approximately 21%, 59% and 34% for the same steels, respectively. In all electrochemical analysis and weight loss test, imidazole proved to be the best inhibitor for the steels investigated.
Acknowledgments
FAPES, CAPES, FINEP, LMC and CNPq.