bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen Terminal Braunschweig – a Research Demonstration Facility Along the Hydrogen Value Chain
Authors: Hasché Frédéric , Sauss David , Oezaslan Mehtap 
Published: December 2024

Two of the greatest challenges in the energy transition are still the transportation and storage of renewable energy. For a green hydrogen economy, electrochemistry will play a major role. This project will show a comprehensive integration of various hydrogen technologies to an integrated physical network at megawatt scale. Our demonstration facility, namely Hydrogen Terminal Braunschweig, is located in Lower Saxony, Germany and was established in Summer 2024 [1].
In the Hydrogen Terminal Braunschweig, the green hydrogen (H2) is generated by the world's first commercially available 1 MW electrolyzer prototype of anion exchange membrane (AEM) technology [2]. The produced H2 from the renewable energy will be stored and used for a heavy-duty truck refilling station (350 bar) as well as transported to internal and external fuel cell test benches via pipelines. In addition to the H2 supply, one of the external consumption points is also fed with electrolysis “waste” heat. The waste heat from the 1 MW electrolyzer is collected, processed in a high-temperature heat pump and supplied via a local heating network. Moreover, the technical interplay and conjunction between electrolyzers and fuel cells with a large battery storage system (1.1 MWh storage capacity) and photovoltaic systems to stabilize the electrical grid will be investigated in detail. Here, a medium-voltage switchgear enables off-grid island operation as well as partial load and full load scenarios of all connected electrical components via switch positions. Last but not least, we will develop an education and training program for various target groups in the field of hydrogen technologies and energy transition in the near future.

References

[1] https://magazin.tu-braunschweig.de/en/pi-post/opening-and-open-day-of-the-hydrogen-terminal-braunschweig/, press releases, 21. June 2024
[2] https://www.enapter.com/aem-electrolysers/aem-nexus/, Aug 2024
Influence of Microwave Drying on Electrochemical Performance and Morphology of Cathode Catalyst Layers for PEM Fuel Cells
Authors: Heider Emanuel Albert , Bayer Michael , Oesterlein Moritz , Joerissen Ludwig 
Published: December 2024

Due to an increasing demand for sustainable energy, the polymer electrolyte membrane fuel cell (PEMFC) and electrolyzer (PEMEL) are considered as a key technology in energy conversion transformation towards climate neutral energy economy. The performance characteristics of a PEMFC is significantly influenced by the microstructure of the catalyst layer, which is formed predominantly during the drying step in the manufacturing process.
In order to improve the performance of PEMFC and hence reducing production costs, research effort has increasingly focused on the drying process. Moreover, energy efficiency of the drying step is considered one of the key driver for manufacturing cost reduction during the mass-market introduction of PEM fuel cells and electrolyzers due to increasing energy costs and the need for reduction of environmental impact.
In the presented work, a drying process for thin-film catalyst layers by making use of microwave radiation is addressed. Drying is performed by exposing the wet film to microwave radiation, leading to a more energy-efficient heat transfer into the wet film compared to conventional convective or infrared-based drying techniques. The dried catalyst layer is subsequently transferred to a polymer electrolyte membrane in a hot-pressing step and is completed with gas diffusion layers to a membrane electrode assembly (MEA). Electrochemical performance of the MEA is characterized on a fuel cell test bench in single cell configuration. The morphology of the structure obtained from microwave drying is analyzed and compared to samples dried in a conventional convective oven.
Although in the microwave drying process at lab scale, an increased tendency to crack formation due to faster drying rate was found , electrochemical performance of the MEAs are comparable to conventionally dried samples. A significant influence of applied pressure during the hot-pressing transfer step on cathode morphology was observed and is discussed with regard to electrochemical performance of the cathode catalyst layers, with a focus on performance in the high current density range.
A Systematic investigation of the electrochemical behavior of the MEA is performed by application of protonic conduction measurements and electrochemical impedance spectroscopy. The pore morphology of cathode catalyst layers, investigated by mercury intrusion porosimetry, is discussed with regard to preparation conditions and electrochemical performance.
Space Charge Effects on the Reaction Kinetics of Metal Exsolution and the Coalescence of Exsolved Nanoparticles
Authors: Weber Moritz Lukas , Jennings Dylan , Šmíd Břetislav , Kindelmann Moritz , Fearn Sarah , Cavallaro Andrea , Gutsche Alexander , Heymann Lisa , Yasin Liam , Cooper Samuel J. , Skinner Stephen J , Dittmann Regina , Aguadero Ainara , Fang Xufei , Lenser Christian , Nemšák Slavomír , Gunkel Felix 
Published: December 2024

Metal exsolution reactions can be driven in fuel electrode materials under the reducing operation conditions of solid oxide cells. The process enables the synthesis of nanostructured catalysts based on the release of a fraction of reducible dopants from a perovskite host to its’ surface and the subsequent nucleation of finely dispersed oxide-supported metal nanoparticles. The performance of such catalysts strongly depends on the nanoparticle characteristics, such as the nanoparticle size and nanoparticle density.
Consequently, dynamic structural and chemical changes of catalyst materials under operation conditions, oftentimes particularly affecting the catalyst surface i.e. the electrochemical interface, play a crucial role for the activity and stability of electrocatalysts. It is essential to understand the mechanistic processes that govern the material response to improve the lifetime of energy conversion devices such as water splitting catalysts or solid oxide cells.
We employ epitaxial thin films with atomically defined surface morphologies to study the exsolution kinetics with respect to the mass transport of Ni dopants from the bulk to the perovskite surface. In addition, we investigate the subsequent growth and coalescence behavior of the exsolved nanoparticles during thermal reduction of the thin film samples. For this purpose, different approaches of defect-engineering are explored to investigate the role of donor-type and acceptor-type defect chemistry as well as the role of dislocations for exsolution reactions.
We demonstrate that the electrostatic interactions of exsolution-active dopants with the surface potential that is correlated to the inherent surface space charge region of perovskite oxides determines the kinetics of metal exsolution in our material system. Moreover, we reveal that defects that form under the reducing reaction conditions at the surface of the perovskite support can accelerate nanoparticle clustering and hence degradation of metal exsolution catalysts. In addition, we show that dislocations may serve as preferential nucleation sites for nanoparticles during metal exsolution. Based on our findings, we derive strategies for the control of the metal exsolution dynamics and for the stabilization of exsolved nanoparticles.
Exploring the Luminescent Properties of Transition Metal Ions in Solids through Theoretical Insights and the Prospects of Machine Learning
Authors: Novita Mega , Ma Chong-Geng , Piasecki Michal , Brik Mikhail G. 
Published: December 2024

This work delineates over a decade of rigorous first-principles computational investigations into compounds doped with transition metal (TM) ions, such as Sc3+, Ti3+, V2+, V3+, Cr3+, Mn3+, Mn4+, Fe3+, Co3+, Ni3+, and Cu3+, within host matrices including α-Al2O3, MgTiO3, and various fluorides, devoid of empirical parameters. Our methodological framework employs discrete variational Xα (DV-Xα) and discrete variational multielectron (DVME) techniques, enhanced by configuration-dependent and correlation corrections to refine accuracy. Notably, our analysis integrates lattice-relaxation estimations through the use of Shannon crystal radii and the Cambridge Serial Total Energy Package (CASTEP), facilitating the examination of pressure-induced effects on lattice structures.
Our comprehensive studies, particularly on α-Al2O3 doped with TM 3d3 ions, have not only successfully replicated known optical characteristics but have also provided new insights into the variation of transition energies across different TM ion charges, alongside pressure-dependent behavior of multiplet energies in alignment with experimental findings. These endeavors highlight the complex interplay of dopant characteristics, including charge states and ionic radii, on the optical properties of host crystals, with precise attention to colorimetry within the International Commission on Illumination (abbreviated CIE) color space framework to evaluate the quality and perception of emitted light.
Furthermore, this work will introduce a discussion on the emerging potential of machine learning (ML) in advancing our understanding and predictive capabilities concerning the luminescence of materials. ML approaches promise to revolutionize the identification of optimal dopant-host combinations, predict novel luminescent materials, and enhance the accuracy of theoretical predictions through data-driven insights. By bridging traditional computational methods with ML, we aim to pave new pathways in the exploration of luminescent materials, potentially leading to innovative applications in lighting, display technologies, and beyond.
(Invited) Self-Recovery of Photodegraded CsPbBr3 Perovskite Nanocrystals and Problems By Irreversible Damage
Authors: Iso Yoshiki , Isobe Tetsuhiko 
Published: December 2024

CsPbBr3 perovskite nanocrystals (NCs) synthesized by a typical hot injection method are adsorbed with surface modifiers. The authors have investigated photodegradation and self-recovery phenomena due to photo-induced desorption by excitation light irradiation and re-adsorption of the surface modifiers in the dark, respectively [1-4]. These phenomena occurred when a dry solid sample of NCs was placed in a sample holder covered with a glass plate to shut out the atmosphere. On the other hand, the dried NCs exposed to the air did not show the self-recovery after photodegradation. This was due to irreversible degradation caused by surface oxidation by atmospheric oxygen. When the dried NCs were covered with a resin film instead of a glass plate, the resin with lower gas barrier properties did not prevent oxidation. However, the use of a resin with higher gas barrier properties confirmed the occurrence of photodegradation and subsequent self-recovery. The authors will present recent results including experiments on nanocomposite films of the NCs dispersed in resin.
References

K. Kidokoro, Y. Iso, T. Isobe, J. Mater. Chem. C, 7, 8546 (2019).

K. Miyashita, K. Kidokoro, Y. Iso, T. Isobe, ACS Appl. Nano Mater., 4, 12600 (2021).

I. Enomoto, Y. Iso, T. Isobe, J. Mater. Chem. C, 10, 102 (2021).

K. Kano, Y. Iso, T. Isobe, ECS J. Solid State Sci. Technol., 12, 056003 (2023).

Figure 1
Composition of Quantum Dot Color Conversion Layer with ZnS Nanoparticle for Facile Ink Formulation and Uniform Inkjet Printing
Authors: Chin Byung Doo 
Published: December 2024

Quantum dot (QD) is excellent material for next-generation displays because of their superior optical properties, such as high quantum efficiency, narrow full width at half maximum, high color purity, and photoluminescence quantum yield. QD demonstrated efficient absorption of blue light, coupled with high color-conversion efficiency, fabricated them suitable for use as color-conversion layers (CCLs). However, robustness in pixel patterning uniformity and a printing resolution should be further studied. Light emission via conversion through QD films or converter pixels still need to be improved because the blue light can directly transmit the QD layers, sometimes leading to insufficient energy to excite the QDs. Thus, many studies on QD CCLs have focused on improving the absorption and emission properties of QDs, formulating CCL resins with enhanced color conversion efficiency. Scattering can alter the optical path and incident angle of the emitted light to increase internal reflection so that light emission of the optical film can be enhanced for excitation of photons. Thus, light scattering particles, such as titanium dioxide (TiO2), silicon dioxide (SiO2), zinc oxide (ZnO), and zirconium oxide (ZrO2) were carefully tuned to achieve outstanding properties as QD CCLs, increasing color conversion efficiency.
In this work, zinc sulfide (ZnS) light diffusers with hydrophobic properties and various size distribution were synthesized. ZnS and QD were mixed in acrylic resin, isobornyl acrylate, with proper composition of initiator and photocrosslinker. The recipe of mixing was considered for a fabrication of QD CCL ink with optimum viscosity, dispersion stability and uniformity, and printability. For the QD-CCL ink with relatively high viscosity, evaluation of jetting profile and pixel-patterning was conducted with commercial ink cartridge, Sapphire QE-256/30AAA (Fujifilm), combined with the custom-built inkjet printer and high-speed camera. With the scale up to 200ppi QD-CCL pattern, the color spectrum, printability, dispersion, optical properties (evaluation of color-emitting image), and surface uniformity were evaluated. Overall, this work will demonstrates the enhanced light converion behavior of QD-CCL layer fabricated by inkjet-printing process and provide a novel evaluation prorocol of uniformity for QD-CCL layer and color conversion device using blue micro-LED.
Scintillation Properties of LaMgAl11O19:Er Crystals with NIR Luminescence
Authors: Nakauchi Daisuke , Kato Takumi , Kawaguchi Noriaki , Yanagida Takayuki 
Published: December 2024

A scintillator is a phosphor that emits photons with several eV when irradiated by ionizing radiations and has been used in applications such as medical diagnostic, security, resource exploration etc. A scintillation detector consists of a scintillator that converts ionizing radiations into photons and a photodetector such as a photomultiplier tube or photodiode that converts photons into electrical signals. Since the conversion efficiency from photon to electrical signal depends on the quantum efficiency of the photodetector, phosphors that emit in the UV–visible region, where the above photodetectors have high sensitivity, have been investigated.
Since the nuclear accident in Fukushima, various countermeasures using materials have been studied for reconstruction. In recent years, scintillators which exhibit luminescence in the near-infrared (NIR) region have attracted attention for remote monitoring applications in high-dose fields. Remote monitoring using scintillators and optical fibers has been proposed to avoid radiation damage to semiconductors and electrical circuits of signal amplifiers involved in measurements. Since the method uses a long optical fiber, the transmission efficiency of scintillation photons in an optical fiber is important. In the NIR region of 800–1700 nm, the transmittance of a quartz fiber is higher than that in the UV–visible region, and the transmission loss can be suppressed. So far, there have been sporadic studies on NIR-scintillators. In the past studies, only emission wavelengths shorter than 1000 nm were monitored because a Si-photodiode was used as the photodetector. On the other hand, InGaAs-based photodiodes enable stable measurement of NIR scintillation photons with wavelengths longer than 1000 nm. In our previous works, various scintillators doped with Nd as an emission center in the NIR region have been developed as candidate materials.
LaMgAl11O19 has been extensively studied in various phosphor fields such as laser and white LED applications. Since LaMgAl11O19 has La3+ sites that can be easily substituted with doped rare-earth ions as an emission center, LaMgAl11O19 doped with various trivalent rare-earth ions such as Ce, Nd, Sm, Eu, Dy, Tm, Yb etc. has been investigated. In addition, compared with conventional oxide scintillators such as rare-earth-based silicate and aluminate compounds, the composition ratio of rare-earth elements is relatively low, and the main component is Al2O3, so the cost of raw materials can be suppressed. However, no research on the scintillation properties for measuring ionizing radiations has been reported so far. In this study, the rare-earth-doped LaMgAl11O19 single crystals were synthesized, and the photoluminescence and scintillation properties were investigated to evaluate the potential applicability for high-dose monitoring applications.
Electrocatalytic Hydrogenation of Nitrogen-Containing Compounds Using a Proton-Exchange Membrane Reactor
Authors: Suga Seiji , Mitsudo Koichi , Osaki Atsushi , Inoue Haruka 
Published: December 2024

Proton-exchange membrane (PEM) reactors, including a membrane electrode assembly (MEA) consisting of a proton exchange membrane and an electro-catalyst supported on carbon, has attracted attention as an useful device for electrocatalytic hydrogenation [1,2]. With this reactor, a continuous flow system can be constructed without the need for a supporting electrolyte, making hydrogenation reactions very ubiquitous. Although there have been several reports on the reductive transformations using PEM reactors, its application for nitrogen-containing organic compounds is still limited.
We herein report the reduction of nitrogen-containing compounds having a cyano or nitro group by using a PEM reactor. We will also report on the reduction of quinoline and other nitrogen-containing aromatic compounds.
[1] Takano, K.; Tateno, H.; Matsumura, Y.; Fukazawa, A.; Kashiwagi, T.; Nakabayashi, K.; Nagasawa, K.; Mitsushima, S.; Atobe, M. Bull. Chem. Soc. Jpn. 2016, 89, 1178–1183.
[2] Mitsudo, K.; Inoue, H.; Niki, Y.; Sato, E.; Suga, S. Beilstein J. Org. Chem. 2022, 18, 1055–1061.
Electrochemical Evaluation of Phenylenediamine/Quinonediimine Redox Systems As Organic Electroactive Materials
Authors: Miyakoshi Kaori , Tajima Toshiki 
Published: December 2024

Quinones are one of the most promising and widely investigated classes of redox active materials for organic aqueous redox flow batteries, because they have advantages such as low cost, excellent reaction rate, and wide variety. However, they have a serious problem of the limited solubility in water. In order to solve the problem, there have been many reports on the introduction of polar functional groups into quinones. On the other hand, quinonediimines are quinone equivalents, which allow the introduction of polar functional groups on the nitrogen atoms. Therefore, quinonediimines are easier to introduce polar functional groups than quinones. With these facts in mind, we evaluated the electrochemical properties of phenylenediamine/quinonediimine redox systems in this work.
First, cyclic voltammetry of 1,2-phenylenediamine (1) and 1,4-phenylenediamine (2) was performed to evaluate their electrochemical reversibility in aqueous (0.1 M KCl/water) and non-aqueous (0.1 M Bu4NBF4/MeCN) solutions. As a result, 2 was reversible, but 1 was irreversible in both solutions. However, the reversibility of 2 was lost on the second scan in the aqueous solution, suggesting that water makes a nucleophilic attack on the oxidized form of 2.
In order to suppress the nucleophilic attack of water, we used and measured the cyclic voltammograms of 2, 2,5-dimethyl-1,4-phenylenediamine (3), and 2,3,5,6-tetramethyl-1,4-phenylenediamine (4) in aqueous and non-aqueous solutions. Their reversibility improved with increasing the number of methyl groups in both solutions. This seems to be due to the steric hindrance of the methyl group, which suppressed the nucleophilic attack of water. In addition, as the number of electron-donating methyl groups increased, the redox potential shifted to the lower potential side.
Finally, in order to verify the electrochemical cycling stability, cyclic voltammetry of 4 was performed with 1000 consecutive scans in aqueous and non-aqueous solutions. In aqueous solution, the redox wave of 4 changed from two waves to one wave. In contrast, the redox wave was maintained after 1000 scans in non-aqueous solution. These suggest that the oxidized form of 4 is stable in non-aqueous solution even under multiple scans, whereas it is unstable in aqueous solution.
We will present the electrochemical properties of various phenylenediamine/quinonediimine redox systems and also introduce the introduction of polar functional groups into them in this presentation.

Figure 1
Synthetic Organic Electrochemistry: From Bulk to Nano Chitin
Authors: Tran Thang Hong , Phan Thu Pham Anh , Kraglund Mikkel Rykær , Tran David , Jacobsen Charlotte , Hjelm Johan 
Published: December 2024

Negatively charged nano chitin with carboxylic groups on the surface are traditionally synthesized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) mediated oxidation of α-chitin in water at pH 10 with the use of sodium hypochlorite (NaClO) or laccase enzyme as a co-oxidant. However, the use of NaClO leads to environmental concerns, while the laccase-mediated process suffers from notable deceleration due to undesired enzyme adsorption onto the chitin substrate. Therefore, we propose an alternative methodology for the fabrication of nano chitin using an environmentally friendly electrochemical approach.
The properties of surface chemistry, crystal structure, and morphology of nano chitin were comprehensively assessed using Zeta analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The size distribution of nano chitin ranged from 700 to 900 nm, with a negative surface charge of approximately -40 mV. Furthermore, new peak appearance at 1730 cm-1 in the FTIR spectrum attributes to the formation of carboxylic groups on the surface of nano chitin.
In conclusion, the application of electrochemical methods shows significant potential for the efficient production of nano chitin through TEMPO-mediated oxidation, offering promising avenues for future research and application. Following synthesis, the resultant product undergoes examination to evaluate its emulsification efficacy, particularly in the context of food applications.