bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method to Fabricate Nanocrystals of Metal Oxides on Carbon Nanotube Surfaces
Authors: Yang Jun , Cheng Junfang , Nakashima Naotoshi 
Published: February 2020

Many attention has been focused on the development of non-precious metal-based electrocatalysts for fuel cells and batteries with high performance, durablity, and scalability for the next-generation eco-friendly energy society[1-3] in order to reduce the cost of the catalysts.
In this meeting, we present a method to fabricate nanocrystals of metal oxides on carbon nanotube surfaces, which was carried out based on the recent finding that pristine multi-walled carbon nanotube/iron phthalocyanine hybrids with a well-defined nanostructure showed an excellent efficiency and durability for oxygen reduction reaction[2], as well as decorating unoxidized-carbon nanotubes with homogeneous Ni-Co spinel (and related) nanocrystals showed a superior performance for oxygen evolution/reduction reactions[3].

References

[1] T. Fujigaya, N. Nakashima, Adv. Mater., 2013, 25, 1666-1681.
[2] J. Yang, F. Toshimitsu, T. Fujigaya, N. Nakashima, J. Mater. Chem. A, 2017, 5, 1184-1191.
[3] J. Yang, T. Fujigaya, N. Nakashima, Sci. Rep., 2017, 7, 45384.
Insight in Mass Transport of Polymer Electrolyte Water Electrolyzer By Systematic Analysis of Liquid and Gas Fed Water
Authors: Schuler Tobias , Kimura Taro , Schmidt Thomas J. , Büchi Felix N 
Published: February 2020

For a broader commercialization of polymer electrolyte water electrolysis (PEWE), it is essential to gain a fundamental understanding of the different components and related losses to increase the overall system efficiency to further decrease the operating cost. Mass transport resistances are the least understood loss category. The use of water feed in the vapor state was utilized to gain insight in the origin of mass transport losses. Vapor feed amplifies governing transport parameters. Limiting current densities were determined and mass transport resistances calculated as a function of temperature (60°C-80°C) and relative gas humidity (60% to >100% rH i.e. oversaturation). The studied configurations with symmetric and asymmetric cell humidification exemplify the major impact of water drag and diffusion on the performance. In addition, a relation between mass transport limitation and high frequency resistance (HFR) measured by electrochemical impedance spectroscopy was established.
The overall mass transport resistance is composed of the sub-resistances of the catalyst layer and the PTL. Partial pressure and PTL type variation were used to isolate these main resistances. The catalyst layer was identified to be the governing resistance in the system such that gas feed electrolysis features two order of magnitude lower current densities in comparison to liquid water electrolysis [1] (see also Figure 1). In the diffusion limited regime of the gas feed cells the limits of liquid water electrolysis are emphasized. The origin of the significant liquid/vapor feed differences was investigated by using different PTL types and IrO2 loadings. The required CCMs were produced by an automated spray coating process where IrO2 loading was varied between 1.0 mg/cm2 and 3.0 mg/cm2.
references
[1] J.M. Spurgeon, N.S. Lewis, Proton exchange membrane electrolysis sustained by water vapor, Energy & Environmental Science, 4 (2011) 2993-2998.

Figure 1
High Efficiency Proton Exchange Membrane Electrolysis: Potential for H2@Scale
Authors: Ayers Katherine E. , Capuano Christopher B , Mani Prasanna 
Published: February 2020

Sustainable sources of hydrogen are a key need for reducing environmental impact of chemical processes, with over 95% of hydrogen for industrial applications currently made from fossil fuels through natural gas reforming or coal gasification. Hydrogen is an important industrial gas, representing a 10 million metric tons/year industry worth $100 billion. While proton exchange membrane (PEM)-based water electrolysis has been commercially available for many years, the production scale has been too small until recently to make large impacts. Also, because of the legacy of the technology in life support applications and lower R&D investment relative to PEM fuel cells, there is still significant room for cost and efficiency improvement of PEM electrolysis through materials and manufacturing advancements.
This talk will discuss recent work in high efficiency catalysts and membranes and fundamental challenges in translating laboratory tests to manufacturable components. While catalyst composition and structure is important in understanding and increasing activity, integration is also a key part of materials and technology development. Solution data is not sufficient for predicting behavior in solid state electrolytes or interfaces with other cell components. Most laboratory experiments also do not provide sufficient information on durability beyond a screening tool for early stages of testing. A holistic approach is needed in materials, processing, and component interactions to advance the field. Current technology scale for PEM electrolysis and pathways for large scale renewable hydrogen production will also provide a framework for potential impact in the near term.
High-Performance Praseodymium Doped Pyrochlore-Type Yttrium Ruthenate Electrocatalysts for Proton Exchange Membrane Water Electrolysis
Authors: Feng Qi , Zhang Zhen , Yao Yao , Li Hui , Wang Haijiang 
Published: February 2020

Proton exchange membrane water electrolysis (PEMWE) is an advanced and effective solution to the primary energy storage which allows for direct production of hydrogen from water. Due to the harsh electrochemical environment (e.g., high anodic overpotential, the presence of strong oxidants, low PH) and the sluggish electrode processes, precious metal compounds have been chosen as electrocatalysts in PEMWE [1]. The development of low-cost, highly active and stable oxygen evolution reaction (OER) catalysts remains an important challenge. Pyrochlore yttrium ruthenate (Y2Ru2O7−δ) has significantly enhanced performance over conventional IrO2 electrocatalyst towards OER and high stability in acid media [2]. However, Y2Ru2O7−δ is limited by its low electrical conductivity related to the n-type semiconducting behavior [3]. Doping the A site of the pyrochlore structure (A2B2O7−δ) is a strategy to improve the electrical conductivity of pyrochlore materials.
In this work, novel yttrium–ruthenates compositions doped with Pr were synthesized by sol-gel method. Electrochemical measurements in acidic media showed that Pr doped yttrium pyrochlore catalysts possess high OER activity and stability. The OER overpotentials of Y2Ru2O7−δ and Y1.8Pr0.2Ru2O7−δ are 310 mV and 300 mV at 10 mA/cm2, which is lower than that of IrO2 (340 mV). The Tafel slopes for Y2Ru2O7−δ and Y1.8Pr0.2Ru2O7−δ are 40 mV/dec and 36 mV/dec, respectively, in comparison with 42 mV/dec for IrO2. The superior activity of Y2Ru2O7−δ and Y1.8Pr0.2Ru2O7−δ measured by current density remained largely unchanged even after 2000 cyclic voltammograms (CVs) cycles, only decreasing by 17% and 5.6%, respectively. In contrast, IrO­2 catalyst lost 46% of its activity.
Figure 1. OER performance of pyrochlore Y2Ru2O7, Y1.8Pr0.2Ru2O7 and reference IrO2 electrocatalysts. (a) CVs cycles from 1st to 2 000th. Inset shows the comparison of current densities for yttrium ruthenate and IrO2 at 1.52 V versus RHE. (b) Tafel plots.
[1] Q. Feng, X.Z. Yuan, G. Liu, B. Wei, Z. Zhang, H. Li, H. Wang, Journal of Power Sources, 366 (2017) 33-55.
[2] J. Kim, P.C. Shih, K.C. Tsao, Y.T. Pan, X. Yin, C.J. Sun, H. Yang, J Am Chem Soc, 139 (2017) 12076-12083.
[3] C. Abate, V. Esposito, K. Duncan, J.C. Nino, D.M. Gattia, E.D. Wachsman, E. Traversa, Journal of the American Ceramic Society, (2010).

Figure 1
First-Principles Models of Phenomena at Li-Metal/Anti-Perovskite Li3ocl Solid Electrolyte Interfaces
Authors: Kim Kwangnam , Siegel Donald J 
Published: February 2020

Solid electrolytes (SE) are a promising strategy for enhancing the safety of lithium-ion batteries (LIBs). Additionally, a viable SE could allow the use of a Li-metal anode, which would increase energy density. Recently, the anti-perovskite compound, Li3OCl (LOC), was suggested as a high conductivity SE, with many follow-on studies investigating Li-ion migration mechanisms and pathways for further increasing conductivity. However, the properties of the interface between LOC and a Li metal electrode are also important for performance. For example, the interaction between a SE and an electrode can change the band edge positions of a SE, narrowing its electrochemical window. Furthermore, wetting of the SE by Li metal is desirable for low interfacial resistance and uniform Li plating.
The present study predicts the interfacial energy, wettability, band edge shifts, and the electrochemical window for interfaces between LOC and a Li-metal anode. The oxygen-terminated interface was determined to be the most stable interface termination. The calculated interfacial work of adhesion suggests that Li will wet LOC with a contact angle of 52.6˚, suggesting the possibility for low interfacial resistance and uniform Li deposition. On the other hand, the strong interfacial adhesion significantly narrows the electrochemical window by shifting both of the LOC band edges by more than 1 eV. Nevertheless, the band edges are predicted to be located above the Li/Li+ level and below the presumed level for a 4.5 V cathode, which implies a sufficiently wide electrochemical window. Our results illustrate a holistic and systematic strategy for characterizing electrode/electrolyte interfaces in solid state batteries.
Accelerated Phase Transition of Pr2NiO4 in the Presence of GDC Interlayer
Authors: Wilson Joshua A. , Wang Yudong , Zhou Xiao-Dong 
Published: February 2020

Praseodymium Nickelate (Pr2NiO4) has the potential to be a cathode for commercial solid oxide fuel cells (SOFCs) due to its high activity towards oxygen reduction. However, when Gd-doped Ceria (GDC) is used as an interlayer to prevent cathode-electrolyte interaction, phase transitions in Pr2NiO4 are accelerated. The accelerated phase transition in Pr2NiO4 decreases the stability of the cell, leading to faster degradation rates in performance over the lifetime of the cell. Identifying how the GDC interlayer affects phase transition will increase the effectiveness of Pr2NiO4 as an SOFC cathode. In this work, the accelerated phase transition of Pr2NiO4 in the presence of GDC will be investigated by: (1) thermo-annealing mixtures of Pr2NiO4/GDC powders at varying compositions and temperatures and, (2) constructing and analyzing cells with Pr2NiO4-GDC composite electrodes and GDC interlayers. XRD will be used to analyze the resulting phase transitions of the annealed powders and of the operated cells. Identifying structural and operational dependencies of this mechanism may help us develop approaches to increase the long-term stability of SOFCs with Pr2NiO4 as cathode material.
Keywords: Nickelate, Doped ceria, phase transition, solid oxide fuel cell
Comparative Study: Effect of Various Wet Impregnations into LaNi1-XFexO3-Δ Cathodic Backbone for Solid Oxide Fuel Cells
Authors: Kang Hung-Sen , Li Haoyu , Lee Min Hwan 
Published: February 2020

The performance of solid oxide fuel cells (SOFCs) is often limited by the sluggish oxygen reduction reaction (ORR) process at the cathode. It is also widely believed that the surface exchange kinetics and surface area of cathodes play a pivotal role in determining the overall cathodic performance. For this reason, various efforts have been made to improve these metrics through nanoscale materials engineering, most notably by the wet impregnation (infiltration) method.[1] While numerous studies have proved the dramatically beneficial effect of infiltration, a systematic comparative study revealing the effect of infiltrated materials and their concentration is lacking.
In this study, we investigated the effect of infiltrated material and nitrate concentration used for sol-impregnation process on the resulting kinetics and rate-limiting steps of ORR. Various infiltrates were chosen based upon the specific merits of each material in terms of electronic/ionic conductivity, oxygen exchange activity and oxygen storage capability. The infiltrates of study includes LaxSr1-xCoyFe1-yO3-δ (LSCF), La1-xSrxMnO3-δ (LSM), Gd1-xCexO2-δ (GDC), Sm1-xCexO3-δ (SDC), Pr1-xCexO3-δ (PDC), Pr6O11 and LaNi1-xFexO3-δ (LNF). Porous LNF was used as the cathodic backbone. For each infiltrate type, sols with different molar concentrations ranging from 0.2 M to 5.0 M were applied for the infiltration process. For every infiltration process, only one infiltration process was performed without a separate sintering/annealing step.
Results showed that an infiltration even with LNF, the same material with the backbone reduced the cathodic polarization resistance (Rp
) from 2.6 (bare LNF) to 0.15 W cm2 at 700 °C, indicating the critical importance of active surface area for cathodic performance in this system. Infiltration with 1.0 M of Pr6O11 rendered the best performance (Rp
= 0.055 W cm2 at 700 °C). With a concentration of 1.0 M or higher, the infiltrate comprises > 20 wt.%, a concentration high enough to infiltrate Pr6O11 throughout the surface of LNF backbone uniformly as observed by electron microscope images. The activation energy of cathodic polarization decreased from 1.75 eV (bare LNF) to 1.0 – 1.2 eV (1.12 eV for 1 M LNF; 1.18 eV for 1 M Pr6O11, 1.06 eV for 1 M LSCF), indicating a shift in the rate limiting step by the infiltration. There was, however, little dependency of activation energy on the molar concentration in a given infiltrate material as long as the concentration is > ~0.5 M. In addition, the dependency on oxygen partial pressure also provided critical clues on the shift in the rate-limiting steps of ORR, and relevant discussion will be provided in the presentation.
This work was supported by the NASA MIRO Program (NNX15AQ01A).
References
[1] D. Ding, X. Li, S. Y. Lai, K. Gerdes, M. Liu, Energy Environ. Sci.
2014, 7, 552.

Figure 1
Preparation and Characterization of Alternative Ni-Based Anode Materials for SOFCs
Authors: Ishibashi Yusuke , Futamura Shotaro , Tachikawa Yuya , Matsuda Junko , Shiratori Yusuke , Taniguchi Shunsuke , Sasaki Kazunari 
Published: February 2020

Introduction

Ni is widely used as the anode material of SOFCs as a cermet containing ionic conductor and electronic conductor. In the SOFC power generation, the oxygen partial pressure in the downstream region of the SOFC systems increases, the metallic Ni can be oxidized to NiO, and thus volume expansion occurs1. Aggregation of adjacent Ni particles can degrade the electrode structure, which makes it difficult to fully utilize the fuel supplied. We have succeeded in fabricating an SOFC anode which is resistant to redox cycling using oxide conductors, La-doped SrTiO3 (LST) and Gd-doped CeO2 (GDC). In this study, we aim to develop (i) a novel electrode in which a metallic Ni catalyst is dissolved from the electrode material and precipitated on the surface of the anode in a reducing atmosphere (Ni-LST-GDC anode), and (ii) a novel electrode using a Ni-based alloy in the electrode framework (Ni-alloy-GDC anode)2,3.

Experimental

Alternative anode materials were prepared via wet process2,3. The cells were prepared by screen-printing the anode and the cathode followed by each sintering process in air. A platinum mesh was used for the current collector, and a Pt-based reference electrode was deposited on the cathode side for overvoltage separation between the anode and the cathode. The electrochemical performance of the fuel cells was evaluated from the I-V characteristics at the operating temperature of 800°C, using 3%-humidified hydrogen fuel. In order to evaluate the electrode activity, the electrode overvoltage was measured. The current interruption method was applied for evaluating the electrode overvoltages.

Results and discussion

Figure 1 shows the I-V characteristics of the cells with the newly prepared Ni-LST-GDC anode, the Ni-impregnated anode, and the LST-GDC anode without adding Ni, at 800°C, in 3%-humidified hydrogen fuel. Regarding the anode voltage and the anodic overvoltage, the Ni-LST-GDC anode exhibited better performance than the anode composed only of LST and GDC. In comparison with the Ni-impregnated anode, however, the cell performance was still lower both in anode voltage, overvoltage, and IR loss. Figure 2 shows STEM micrographs indicating that the Ni catalyst particle precipitated could locate on the GDC. Anode materials design principles of alternative Ni-based anodes will be discussed. But most of Ni particles located on the electron-conductive LST. In contrast, the cell with Ni-alloy anode exhibited comparable performance compared to that with the Ni-SSZ cermet.
References
[1] Q. Fang, L. Blum, R. Peters, M. Peksen, P. Batfalsky, D. Stolten, Int. J. Hydrogen Energy, 40, 1128-1136 (2015).
[2] X. Shen and K. Sasaki, J. Power Sources, 320, 180 (2016).
[3] S. Futamura et al., J. Electrochem. Soc., 164 (10), F3055 (2017).

Figure 1
Self-Referencing Luminescence Thermometry with Probes Emitting Red and NIR
Authors: Dramicanin Miroslav 
Published: February 2020

Luminescence of any substance is strongly affected by temperature. Therefore, in principle, any material may be utilized to determine temperature from changes in its excitation and emission band energies and bandwidths, emission intensities, ratios of intensities of different emission bands, polarization/anisotropy, emission decay- and rise-times [1, 2]. However, for practical applications in thermometry, materials and material’s systems ought to be thermally and chemically stable, have sufficient brightness and photostability, and their luminescence should notable change with temperature.
Today, lanthanide and transition metal activated phosphors, quantum dots, organic dyes and pigments, and metal-organic complexes and frameworks are common choices for luminescence thermometry probes. Among them, due to compatibility with the biological “optical window” and low interference from light scattering and background fluorescence, those probes emitting in the red and near-infrared parts of the electromagnetic spectrum are of exceptional interest for bio-medical applications.
Here, the focus is on the emission intensity ratio and emission decay based luminescence thermometry methods because they are self-referencing (do not require reference measurements) and are not affected by changes in measurements conditions. The principle of operation of these methods is presented along with corresponding figures of merit. Then, the main red- and NIR-emitting materials utilized for thermometry probes are listed and their performance is discussed. These include Eu3+, Nd3+, Cr3+ and Mn4+ activated phosphors, PbSe, PbS, CdSe/ZnS and PbS/CdS/ZnS core–shell, ZnS−AgInS2 alloy, ZnS:Mn2+, CsPbCl3:Mn2+ quantum dots, and organic Pluronic F127–Cy5.5 hybrid probe and metal-organic Eu0.0069Tb0.9931-2,5-dimethoxy-1,4-benzenedicarboxylate probes. Finally, several examples of multifunctional applications of these probes and methods is shown, such as in combined bio-imagining and thermal sensing, photothermal therapy and combined physical and chemical sensing.
References:

M.D. Dramićanin, Luminescence Thermometry: Methods, Materials, and Applications 1ed, Elsevier Ltd, ISBN: 978-0-08-102029-6, 2018.

M.D. Dramićanin, Sensing temperature via downshifting emissions of lanthanide-dopedmetal oxides and salts. A review, Methods Appl Fluoresc 4 (4) (2016) 23. 42001.
Luminescence Thermometry with Dy3+ Activated Na0.25K0.25Bi0.5TiO3
Authors: Medic Mina , Dacanin Far Ljubica , Kuzman Sanja , Petrovic Dragoslav M. , Dramicanin Miroslav , Lukic Petrovic Svetlana R. 
Published: February 2020

In this report we present synthesis and thermographic properties of Dy-activated Na0.25K0.25Bi0.48Dy0.02TiO3 powder. The material is prepared by a solid-state reaction using TiO2, Bi2O3, Na2CO3, K2CO3 and Dy2O3 as precursor materials. Starting powders were ball milled in ethanol for 12 h, then dried and calcined at 850°C for 2 h. Subsequently, the obtained powder was additionally milled in ethanol for 12 h, and finally sintered at 850°C for 4 h. X-ray diffraction measurement revealed that NKBT sample exhibits a tetragonal perovskite structure, belonging to the P4bm space group, without impurities. Emission spectra showed characteristic bands of Dy3+ ions with pronounced emission originating from f–f electronic transitions. A dominant band in the blue region with maximum at around 477 nm originates from magnetic-dipole 4F9/2→6H15/2 transition, while another one in the yellow region peaking at around 574 nm comes from electric-dipole 4F9/2→6H13/2 transition. A small intensity high-energy band centered at around 457 nm originating from 4I15/2→ 6H15/2 transition, provided the possibility to use this type of emitting material as temperature sensor in luminescence thermometry. Temperature readings from material’s luminescence emission were acquired via relative luminescence emission intensity measurements (LIR). This approach uses the ratio of intensities of two specific emission bands, in this case emissions from 4F9/2 and 4I15/2 excited states to the 6H15/2 ground state [1, 2]. With this material, relative sensitivity of about 2% K-1 and temperature resolution of 0.5 K of thermometry have been achieved.
References:

Ž. Antić, M. D Dramićanin, K. Prashanthi, D. Jovanović, S. Kuzman, T. Thundat, "Pulsed Laser Deposited Dysprosium-Doped Gadolinium–Vanadate Thin Films for Noncontact, Self-Referencing Luminescence Thermometry", Advanced Materials, Volume 28(35), 7745-7752 (2016).

M. D Dramićanin, "Sensing temperature via downshifting emissions of lanthanide-doped metal oxides and salts. A review", Methods and Applications in Fluorescence, Volume 4(4), 042001(23 pp) (2016).
Structure Solution and Luminescence Properties of a Phosphosilicate Compound
Authors: Kim Ha Jun , Unithrattil Sanjith , Im Won Bin 
Published: February 2020

Materials with different frameworks and topologies have an important place in various scientific applications, and several such compounds have been developed over the past few years. The insights offered by such developments have altered the thought process behind material formation and their potential topologies. Materials with certain particular frameworks are often channelized toward specific applications, based on the understandings then; however, these materials may also offer a considerable number of topologies and are finding new applications that were considered unviable a few decades ago. Among the most prominent and well-understood materials that form such frameworks are aluminosilicates. Although most of these classes of compounds are natural in origin, specific applications based on these materials have only recently been developed, because of limitations in understanding their precise chemical and structural details.
In this work, we synthesized a new phosphosilicate compound, using a microwave-assisted solid-state synthesis method. The lattice parameters of the crystalline compound were estimated from first-principle calculations, and the space group was identified through a least-squares method. The detailed structure solution was carried out through a simulated annealing method, which estimated the agreement between the assumed model and the observed diffraction pattern and chemical restraints. Therefore, the crystal structure solved was verified through the Rietveld refinement and maximum-entropy method (MEM) analysis. High-resolution transmission electron microscopy (HRTEM) was also used to confirm the lattice parameters of the solved crystal structure. Photoluminescence properties of the structure were also studied by activating it with the broadband-emitting activator (Eu2+), and the structural and luminescence correlation was also verified.
Figure 1. Rietveld refinement of the powder X-ray diffraction profile of NaCa3PSiO8. Data (point) and fit (lines), different profile, and expected reflection positions are displayed. The inset shows the coordination environment of the major cations in the structure.

Figure 1