bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unraveling the Synthesis of Positive Electrodes for Na-Ion Batteries by in Situ XRD
Authors: Xu Mingfeng , Laurier Jade , Akhtar Mainul , Bianchini Matteo 
Published: February 2024

In situ diffraction studies can capture transient crystalline phases forming during chemical reactions. Whether the reaction is a chemical solid-state synthesis, or an electrochemical intercalation process within typical active compounds used as battery electrodes, proper sample environments allow nowadays to perform in situ diffraction experiments with high temporal and angular resolution even when using laboratory diffractometers. In both cases, the time-resolved nature of the experiments allows to obtain a greatly increased amount of information. For example, in the synthesis of inorganic materials, reactions often yield non-equilibrium kinetic byproducts instead of the thermodynamic equilibrium phase [1]. On the other hand, often stable compounds cannot be synthesized. To rationalize that, the competition between thermodynamics and kinetics occurring during the process need to be investigated in real time. Fully determining the reaction pathway is a key requirement to achieve the rational synthesis of target materials [2, 3]. In this presentation, recent unpublished examples will be reported from our work applying in situ XRD to understand the synthesis of cathode materials for Na-ion batteries. We focus on layered materials and on the relationship between P2 and P3 polymorphs in series of samples of the same composition NaxDyNizMn1-y-zO2 (where D is a substitutional element and Ni and Mn are in divalent and tetravalent oxidation state, respectively) and highlight the transformation of a phase into the other during calcination. Moreover, we provide electrochemical and morphologic characterizations of the target compounds, aiming to answer the question: does one or the other polymorph offer better performances? The charge compensation mechanism, involving Ni redox but also O redox, will be reported. Finally, the presentation will also briefly cover the investigation of novel solid-state synthesis routes for cathodes of the fluorophosphate Na3V2(PO4)2F3-xOx family.
References:
[1] M. Aykol et al., Science Advances, 2018, 4 (4), 148.
[2] Z. Jiang et al., Journal of Materials Chemistry C,
2017, 5 (23), 5709-5717.
[3] M. Bianchini, J. Wang et al., Nature Materials. 2020, 19 (10), 1088-1095.

Figure 1
(Invited) Accelerating Electrocatalysts’ Activity and Stability Assessments
Authors: Cherevko Serhiy , Jenewein Ken , Geuß Moritz 
Published: February 2024

The standard approach to new electrocatalysts development and testing is prohibitively slow. Moreover, it fails to meet the complexity of real devices. As a rule, it consists of routinely repeated steps, including synthesis, physicochemical characterization, and electrochemical measurements. The latter is typically based on the application of rotating disk electrodes (RDE) as conductive solid support to carry electrocatalysts and bulk electrochemical cells with liquid electrolytes as the reaction media.
The current work will contain two main parts presenting our recent approaches to tackling the abovementioned limitations of the classical electrochemical test systems. As a representative example, oxygen evolution reaction (OER) electrocatalysis in electrolytes of different pH is taken. It will be shown that bearing in mind the intrinsic limitations of the aqueous mode systems (AMSs), significant acceleration of electrocatalysts’ activity and stability measurements can be achieved by using coupled techniques based on different scanning flow cells.1, 2 This approach is ideal for quick multidimensional parameter space screening. However, further tests in real systems are necessary after identifying promising candidates. It will be shown that also this step can be accelerated using model gas diffusion electrode (GDE)-based setups.3, 4 Moreover, qualitatively different information, e.g. electrocatalyst dissolution assessment, can be achieved using GDE setups coupled to external analytics like inductively coupled plasma mass spectrometry (on-line ICP-MS). While it will be shown that using two approaches, facile screening and real-device level proof tests, are feasible, limitations and challenges will also be discussed, together with further directions to develop these techniques.

References:

A. Kormányos, K. J. Jenewein and S. Cherevko, Trends in Chemistry, 4, 475 (2022).

K. J. Jenewein, G. D. Akkoc, A. Kormányos and S. Cherevko, Chem Catalysis, 2, 2778 (2022).

Y.-P. Ku, K. Ehelebe, A. Hutzler, M. Bierling, T. Böhm, A. Zitolo, M. Vorokhta, N. Bibent, F. D. Speck, D. Seeberger, I. Khalakhan, K. J. J. Mayrhofer, S. Thiele, F. Jaouen and S. Cherevko, Journal of the American Chemical Society, 144, 9753 (2022).

K. Ehelebe, J. Knoppel, M. Bierling, B. Mayerhofer, T. Bohm, N. Kulyk, S. Thiele, K. J. J. Mayrhofer and S. Cherevko, Angew Chem Int Ed Engl, 60, 8882 (2021).
(Invited) Crosscutting Materials Innovation for Transformational Chemical and Electrochemical Energy Conversion Technologies—Solid Oxide Cells
Authors: Njodzefon Jean-Claude , Sauter Ulrich , Weber Andre 
Published: February 2024

The Solid Oxide Cell (SOC) primarily operated as Solid Oxide Fuel Cell (SOFC) converts the chemical energy of a fuel such as hydrogen directly into electricity with very high efficiencies. Reverse operation of the exact same SOCs—as Solid Oxide Electrolysis Cells (SOEC) converts electrical energy into chemical energy by using the electricity to split chemical molecules such as steam, carbon dioxide or mixtures of both into hydrogen, carbon monoxide or mixtures of both respectively.
The SOC is basically a gas-tight and oxide-ion conducting solid electrolyte, sandwiched between porous oxide ion – and electron-conducting electrode materials—the oxygen electrode and the fuel electrode where the electrochemical conversions occur.
Irrespective of operation mode, the choice of SOC materials and processing routes generally aim for maximum performance and lifetime at chosen conversion rate and efficiency at nominal operation. This is as much as the technology can intrinsically offer and by far not enough to guarantee either profitable production of electricity or chemicals hydrogen, carbon monoxide or both. Ultimately the materials and manufacturing costs of the cell, stack, module, and system play a key role in the involved invest. Generally, operation costs such as cost of natural gas or electricity as well as maintenance costs are much more significant in determining the profitability of the technology than the investment costs. These technology-independent factors can in turn orientate the technologist to optimize the cell for either for maximum efficiency or conversion rate capability.
In this talk we will discuss specific SOC materials such as doped zirconia, doped ceria, manganates, cobaltites, and titanates. Intrinsic limitations and advantages with respect to performance, durability and costs; how they are withstanding the test of time and the ever decreasing operation temperature from micro/nano structuration, infiltration and exsolution of electrocatalysts through switching of cell supports. We will give a perspective on the dependency of cell material choices based on technology use cases and boundary conditions

Figure 1
Systematic First-Principles Calculations of Ce3+-Dopant in Garnet-Type Oxide Phosphors
Authors: Mohd Razip Nora Izzati Binti Binti , Novita Mega , Ogasawara Kazuyoshi 
Published: February 2024

A study of Ce3+-doped oxide phosphors was performed using first-principles calculations based on the relativistic DV-Xα method. In particular, we focused on the Ce3+-doped garnet-type oxides, which have potential applications in solid-state lighting and display devices. The electronic structure and optical properties of the phosphors were analyzed. The energy levels of the Ce3+ ions were affected by the coordination number and the crystal field strength of the surrounding oxygen ions. In addition, the crystal structure of the material had a significant impact on the energy levels of the Ce3+ ions, with different crystal structures leading to different energy levels.
The Ce3+ ion is substitutionally incorporated in the garnet lattice, and the 4f electron of Ce3+ plays an important role in the luminescence of the material. The emission wavelengths of the 5d-4f transition energy of Ce3+ can be tailored by varying the crystal structure and the composition. The 5d orbitals of Ce3+ are substantially affected by the crystal field splitting while the amplitude of crystal field splitting (εcfs) is caused by many parameters: coordination number, symmetry of Ce3+ site, and bond lengths between the Ce3+ ion and the oxygen ions (O2-). This study incorporated the following computational conditions: i) lattice relaxation, ii) the choice of the exchange-correlation potential, and iii) Slater’s transition state method. The effects of these conditions were analyzed. In addition, the correlations among physical properties and electronic structure parameters were also investigated in detail.
The first-principles calculation results were compared to the experimental data to validate the accuracy of the theoretical models, which showed a good agreement between the experimental and predicted values.
Theoretical Analysis of Anomalous Emission of Eu2+ in Crystals By First-Principles Calculation
Authors: Okamura Tatsunori , Ogasawara Kazuyoshi 
Published: February 2024

The 5d-4f transition energies of lanthanides are very versatile, especially the 4f65d1-4f75d0 transition energy of Eu2+ has high luminescence efficiency and is used in various luminescent materials such as phosphors like SrxCa1-xAlSiN3: Eu2+, scintillators, and solid-state lasers, etc. However, there are materials that do not undergo pure 5d-4f transitions, showing the so-called anomalous luminescence instead. The anomalous luminescence is caused by the formation of excitons due to the overlap of the 5d level of Eu2+ with the conduction band and the transition of electrons from the conduction band to the 4f level, resulting in a shift to a lower energy than the general 5d-4f transition energy. A more detailed analysis of this phenomenon is important for the development of novel luminescent materials using Eu2+.
In this study, we aimed to theoretically analyze the anomalous luminescence based on first-principles electronic structure calculations. The model clusters of Eu2+-doped crystals consisting of Eu2+ at the substitution site and the surrounding ions were created. Then molecular orbital calculations were performed by the relativistic discrete-variational Xα (DV-Xα) method and subsequently multiplet calculations were performed by the relativistic discrete-variational multi-electron (DVME) method. These first-principles calculations were carried out for Eu2+-doped crystals that show anomalous luminescence and those that do not show anomalous luminescence, and the electronic states of these materials were compared in detail.
First-Principles Calculations of the Optical Spectra of Uranium Ions in Oxide Crystals
Authors: Masago Toshiki , Ogasawara Kazuyoshi 
Published: February 2024

Recently U6+-doped phosphors are attracting attentions as potential green phosphors for the white LED application. However, the origins of the peaks in the optical spectra in some U-doped phosphors have not been clarified yet. For the development of the novel uranium phosphors, detailed analysis of the absorption and emission mechanisms of these materials is indispensable.
In this study, we have performed the first-principles electronic structure calculations of U in oxide crystals using the relativistic discrete-variational multi-electron (DVME) code which is a configuration-interaction calculation program based on the four-component fully relativistic wave functions obtained by the relativistic discrete-variational Xα (DV-Xα) molecular orbital method. The optical spectra due to the charge transfer transitions of U6+ in oxides were calculated using the explicitly obtained many-electron wave functions. For comparison, the 5f-6d transitions of U3+ in oxide crystals were also calculated and the influence of the valency was investigated. The theoretical spectra were compared with the experimental spectra and the origins of the peaks were clarified based on the configuration analysis of the corresponding relativistic many-electron wave functions.
(Keynote) Metallaelectro-Catalyzed Bond Activations
Authors: Ackermann Lutz 
Published: February 2024

Oxidative C–H activation has emerged as an increasingly powerful tool in molecular syntheses.[
1] Despite major progress towards atom and step economy, these transformations largely rely on precious metal catalysts and stoichiometric amounts of toxic metal oxidants, compromising the overall sustainability of the C–H activation strategy. In contrast, employing electrooxidation in lieu of reactive chemical oxidants prevents undesired waste formation through oxidant economyand offers efficient use of renewable energies from sustainable sources for chemical bond formation.[2] Inexpensive Earth-abundant 3d metal[3] cobaltaelectrocatalysis set the stage for molecular syntheses at a unique level of resource economy.[4] Our studies towards metallaelectrocatalytic C–H and C–C activation will be discussed, with a topical focus on sustainable base metals.[5]

References

[1] a) L. Ackermann, Acc. Chem. Res. 2014, 47, 281–295; b) C. S. Yeung, V. M. Dong, Chem. Rev.
2011, 111, 1215–1292.
[2] a) P. Gandeepan, L. H. Finger, T. H. Meyer, L. Ackermann, Chem. Soc. Rev.
2020, 49, 4254–4272; b) LA, Acc chem Rex 2020, C. Ma, P Fang, T.-S. Mei, ACS Catal.
2018, 7179–7189.
[3] P. Gandeepan, T. Müller, D. Zell, G. Cera, S. Warratz, L. Ackermann, Chem. Rev.
2019, 111, 2192–2452.
[4] Y. Qiu, M. Stangier, T. H. Meyer, J. C. A. Oliveira, L. Ackermann, Angew. Chem. Int. Ed.
2018,
57, 14179–14183; b) Y. Qiu, W.-J. Kong, J. Struwe, N. Sauermann, T. Rogge, A. Scheremetjew, L. Ackermann, Angew. Chem. Int. Ed.
2018,
57, 5828–5832.
[5] a) R. Mei, N. Sauermann, J. C. A. Oliveira, L. Ackermann, J. Am. Chem. Soc.
2018,
140, 7913–7921;N. Sauermann, T. H. Meyer, C. Tian, L. Ackermann, J. Am.
Chem. Soc.
2017,
139, 18452–18455.

Figure 1
Catalytic Activity of Atomic Metals Clusters Decorated Polyaniline Electrodes in Electrochemical Oxidation of 1-Propanol
Authors: Yoshida Shohei , Okamoto Keisuke , Kurioka Tomoyuki , Chen Chun-Yi , Chakraborty Parthojit , Nakamoto Takamichi , Sone Masato , Chang Tso-Fu Mark 
Published: February 2024

Electrochemical sensors are capable to fast-detect chemicals with a high sensitivity at a low cost. Thanks to these advantages, electrochemical sensors are promising for detections of biomolecules, such as glucose, dopamine, uric acid, etc. The catalytic electrode in a electrochemical sensor is composed of noble noble metals, such as Au and Pd,and a suppoorting material. Polyaniline (PANI)[
1]is an ideal supporting material for noble metal clusters because of its good electrical conductivity, high stability, large active surface area, and simple preparation process. Recently, PANI decorated with atomic level noble metal clusters is report to show distinct catalytic activity for the electrochemical oxidation of alcohols.[1] However, the effects of the number of the metal atoms in such clusters and the sequence of the atomic level deposition step on their electrocatalytic activity for electrochemical alcohol oxidation remain unexplored.
In this presentation, the effects of the number of the metal atoms and the sequence of the atomic level deposition step in the atomic level noble metal clusters on the catalytic activity in electrochemical oxidation of 1-propanol (1-PrOH) are reported. The PANI was deposited on a Pt disk electrode (ϕ = 3 mm) by electrochemical polymerization in a 2 M HBF4 aqueous solution containing 0.1 M of aniline. Then, the PANI deposited electrode was decorated with mono-atomic noble metal clusters, bi-atomic, tri-atomic, or tetra-atomic noble metal clusters. The atomic noble metal clusters are denoted as PdxAuy, where x represents the number of Pd atoms in a cluster and y is the number of the Au atoms. The sources of the Pd and Au were K2PdCl4 and KAuCl4, respectively.. Fig. 1 shows the schematic procedures for fabricating a bi-atomic pure Pd (Pd2) decorated PANI electrode and a PdAu decorated PANI electrode. The catalytic activity for the electrochemical oxidation of 1-PrOH was evaluated by performing cyclic voltammetry measurements with an aqueous solution containing 0.5 M 1-PrOH and 1 M KOH.
The catalytic activtiy was found be higher for the Pd2 and Pd4 decorated PANI electrodes than those of the Pd1 and Pd3 decorated PANI electrodes, which revealed odd-even pattern effects as reported in a previous study.[
1] Furthermore, the catalytic activity was found to be affected by the sequence in deposition of the atomic level noble metal clusters.

Reference

[1] A. P. Jonke, J. L. Steeb, M. Josowicz, J. Janata, Catal Lett
2013, 143, 531–538.

Figure 1
DFT Simulations on the Nitrogen Reduction Reaction Activity of Transition Metal Nitride and Oxynitride
Authors: Liu Ji , Glauber Jean-Pierre , Lorenz Julian , Bragulla Sebastian , Müller Björn , Harms Corinna , Wark Michael , Devi Anjana , Nolan Michael 
Published: February 2024

Transition metal nitride (TMN) is a promising material towards the energy related applications including catalysis and energy storage.1 The sluggish nitrogen reduction reaction (NRR) due to the high energy input to activate N2 remains a significant challenge for NRR electrocatalysts. The surface N of TMN can be a solution to this with initial N vacancy formation via hydrogenation steps and ammonia formation. In addition, with a small amount of surface oxygen present in the catalyst surface, the resulting oxynitride seems very interesting and active towards NRR.2 But the mechanism behind this is not yet understood.
In this study, we first focused on the modelling of the structure of metal nitride (ZrN) and oxynitride (ZrOxNy/ZrN) surfaces. The structure of oxynitride is obtained by running molecular dynamics (MD) calculations at both room temperature and experimental deposition temperature (90°C and 750°C). NRR reaction is then studied via the Mars-Van Krevelen (MvK) mechanism with introducing surface N vacancy and subsequent N2 adsorption and N filling. With computing the reaction energy and activation barriers of key reaction steps on both ZrN and ZrOxNy/ZrN, we can find a clue on how surface N of TMN helps to activate N2 and the role of small amount of surface oxygen on activating N2. To study the origin of small amount of oxygen, reaction energies and full reaction pathway along the deposition process are computed and plotted. Finally, dopant effect will be modeled with transition metal dopants (e.g. Cu and Hf) at surface region to study any localized electronic effect on NRR.
These results can be useful to design and deposit ZrN acting as effective NRR electrocatalysts.
References
[1] Luo, Q.; Lu, C.; Liu, L.; Zhu, M., A review on the synthesis of transition metal nitride nanostructures and their energy related applications, Green Energy & Environ. 2023, 8, 406
[2] Young, S. D., Ceballos, B. M., Banerjee, A., Mukundan, R., Pilania, G., & Goldsmith, B. R, Metal Oxynitrides for the Electrocatalytic Reduction of Nitrogen to Ammonia. J. Phys. Chem. C. 2022, 126, 12980-12993.
Choice of Surfactants and Its Impact on the Capacitive Behaviour of PEDOT-Carbon Nanotubes Composites Synthesised at the Liquid|Liquid Interface
Authors: Rojas-Sanabria Nicolas , Quintero Jaime Andrés Felipe , Holzinger Angelika , Scanlon Micheal D. 
Published: February 2024

Conductive polymers (CP), such as poly(3,4-ethylenedioxythiophene) (PEDOT), exhibit exceptional physical, chemical, and electrical properties [1] that position them as effective alternatives for the manufacture of electrode materials for energy storage applications [2]. In order to increase the stability of the polymer, and thus extend the lifespan of the supercapacitor device, surfactants are added to the polymer matrix [3]. Among the most used surfactants, poly(styrenesulfonate) (PSS) has shown to enhance the stability of polymers and has positioned itself as the surfactant of preference while working with PEDOT. However, a decrease in the capacity and conductivity of the material is also exhibited [4]. Here, the addition of differently charged surfactants during the four-electrode polymerisation of PEDOT at a polarised aqueous|organic interface (ITIES) was studied under ambient conditions. The results show a considerable effect of the surfactant on the morphology of the polymer that translates into a change of the charge storage capacity. Cetyltrimethyl ammonium bromide (CTAB) shows potential as a suitable alternative to PSS for the synthesis of CP-CNT composites. Finally, multi-walled carbon nanotubes (MWCNTs) are dispersed on the aqueous phase containing the surfactant and later incorporated into the polymer film during the interfacial synthesis of PEDOT-MWCNT composites.
References
[1] C. Zhan et al., J. Mater. Chem. C. 2017, 5(7):1569-85
[2] I. Gualandi et al., Sci. Rep. 2016, 6, 35419.
[3] Q. Yang et al., J. Electroanal. Chem., 2014, 728, 140-147.
[4] R.A. Lehane, et al., J. Am. Chem. Soc. 2022 144 (11), 4853-4862

Figure 1
Hydrogen Reduction Reduction (HRR)
Authors: Wang Hai-Xu , Surendranath Yogesh 
Published: February 2024

The year 2023 marks the bicentennial of the discovery of heterogeneous H2 catalysis. Nowadays, the hydrogen oxidation reaction (HOR), which converts H2 to protons (H+), is one of the most important transformations in energy research. Meanwhile, hydrogenation reactions, which transfer net H-atoms (H·) to organic substrates from H2, play pivotal roles in various chemical industries. In comparison, it is surprising to see that a heterogenous catalytic reaction that directly converts H2 to hydrides (H–) still remains elusive. Hydride transfer is a critical elementary reaction step that spans biological catalysis, organic synthesis and energy conversion. Conventionally, hydride transfer reactions are performed using (bio)molecular hydride reagents under homogeneous conditions. Here we report a conceptually distinct heterogeneous hydride transfer reaction via the net electrocatalytic hydrogen reduction reaction (HRR), which reduces H2 to hydrides. The reaction proceeds by H2 dissociative adsorption on a metal electrode to form surface M−H species, which are then negatively polarized to drive hydride transfer to molecular hydride acceptors with up to 91% Faradaic efficiency. The hydride transfer reactivity of surface M−H species is highly tunable, and, depending on the electrode potential, the thermodynamic hydricity of Pt−H on the same Pt electrode can continuously span a range of >40 kcal/mol.
In addition to this electrochemical transformation, we further developed an alternative strategy to achieve heterogeneous hydride transfer on dispersed metal catalysts under non-electrochemical conditions. In the presence of a base, deprotonation of surface M-H builds up electron density at the metal surface and thereby causes spontaneous polarization which can then drive hydride transfer from metal nanoparticles. Based on this, HRR can be performed under standard hydrogenation conditions with the addition of a base using dispersed metal catalysts, and the surface hydricity is now controlled by the solution basicity. We further demonstrate that this non-electrochemical HRR method can be applied to NADH regeneration which is closely related to industrial biocatalysis. The discovery of HRR reveals the fundamental hydride transfer reactivity of surface M-H species as well as its polarization-dependent nature. Both the electrochemical and non-electrochemical HRR methods establish sustainable strategies for accessing reactive hydrides directly from H2.

Figure 1