bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancing Selectivity and Efficiency in Carbon Dioxide Reduction to C2 Products through Spatial Confinement of Copper Species
Authors: Hung Sung-Fu 
Published: December 2024

Carbon dioxide reduction reaction (CO2RR) into multi-carbon products such as ethylene and ethanol offers a promising avenue for both mitigating CO2 levels in the atmosphere and producing valuable chemicals. Techno-economic assessments indicate that achieving a current density of 300 mA/cm2 in CO2RR to C2+ products is crucial. Recently, we have made strides in enhancing both current density and selectivity through the utilization of flow systems and the implementation of spatial confinement strategies.
Our approach involves synthesizing copper nanoparticles within carbon nanotubes (CNTs) to mitigate overpotential and enhance the selectivity of multi-carbon product formation. The confined environment within the CNTs serves to concentrate CO2RR intermediates, thereby promoting the activity and selectivity of the carbon dioxide reduction reaction. As a result, our composite catalyst demonstrates a Faradaic efficiency of 73.96% and a current density of 591.68 mA/cm2for C2 products at 800 mA/cm2.
Further enhancing the activity of copper species, we design a tubular metal-organic-framework (MOF)-derived copper catalyst that generates copper nanoclusters within its structure, leveraging the spatial confinement effect to boost the activity and selectivity of CO2RR. This catalyst achieves a Faradaic efficiency of 71% and a current density of 710 mA/cm2 for C2 products at 1000 mA/cm2.
Analysis of operando Raman spectra, reveals crucial intermediates generated during CO2RR, shedding light on mechanisms underlying overall catalytic activity improvements. Through these spatial confinement strategies, we aim to significantly reduce carbon dioxide, advance towards achieving net-zero emissions, and pave the way for the industrialization of CO2RR.
Engineering of High-Surface Area Carbons Supports with Optimized Properties for Pt/C PEMFC Catalysts Design
Authors: Martin Julian , Küspert Sven , Christmann Kläre , Marić Robert , von Holst Miriam , Fadlullah Hassan , Vierrath Severin , Zamel Nada , Fischer Anna 
Published: December 2024

Proton Exchange Membrane Fuel Cells (PEMFCs) for heavy-duty applications require the development of carbon-supported Pt-based electrocatalysts for oxygen reduction reaction (ORR) with enhanced activity and prolonged durability compared to current systems.[1,2] While various factors affect the performance of the catalyst layer within the Membrane Electrode Assembly (MEA); at the catalyst level, the size and distribution of Pt nanoparticles on the carbon support, as well as the properties of the carbon support itself, play a crucial role in determining the overall performance. Therefore, engineering of the carbon support, including morphological and physicochemical properties, is a potent strategy not only to enhance Pt nanoparticle dispersion, anchoring, and positioning but also to mitigate ionomer poisoning, thereby maximizing Pt utilization for ORR.[3,4,5] Additionally, carbon support engineering directly influences the structural properties of the catalyst layer, which is pivotal for improving accessibility and oxygen transport at the MEA level.
In this contribution, we introduce the synthesis of a high-surface area carbon support (hs-C) with customized morphological and physicochemical characteristics. Our method enables precise adjustment of critical support parameters, leading to an unparalleled toolbox for advanced Pt/C catalyst design.
We thoroughly examined the morphological and physicochemical properties of the resulting "designer" carbons and derived Pt/hs-C catalysts. A systematic investigation of the impact of the carbon support properties on the ORR catalytic activity in acidic media at the Rotating Disk Electrode (RDE) level was conducted as well as structure-function relationships at the MEA level derived, demonstrating the huge potential of carbon support design in improving Pt utilization and PEM-FC performance.
Note: J.M., S.K. and K.C. have equally contributed to this work.

References

[1] D.A. Cullen, K.C. Neyerlin, R.K. Ahluwalia, R. Mukundan, K.L. More, R.L. Borup, A.Z. Weber, D.J. Myers, A. Kusoglu, A. Nature Energy. 2021, 6, 462–474.
[2] K. Kodama, T. Nagai, A. Kuwaki, R. Jinnouchi, Y. Morimoto, Nature Nanotechnology, 2021, 16, 140–147.
[3] P. Lang, N. Yuan, Q. Jiang, Y. Zhang, J. Tang, Energy Technology, 2020, 8, 1900984.
[4] S. Ott, A. Bauer, F. Du, T.A. Dao, M. Klingenhof, A. Orfanidi, P. Strasser, ChemCatChem, 2021, 13, 4759–4769.
[5] Islam, M. N.; Mansoor Basha, A. B.; Kollath, V. O.; Soleymani, A. P.; Jankovic, J.; Karan, K. Nat. Commun.
2022, 13 (1), 6157.
Elucidating the Evolution of the Iridium Oxide Catalysts’ Surface: From Activation through Operation to Degradation Modes
Authors: Roiron Camille , Wang Cliffton , Zenyuk Iryna V. , Atanassov Plamen , Zargarian Shabnam 
Published: December 2024

Iridium oxide nanoparticles as self-supported catalysts for the oxygen evolution reaction (OER) in proton exchange membrane water electrolyzers (PEMWE) have been used for a decade because of their stability in acidic environments. The community has in general accepted that the amorphous and rutile structures of this oxide have distinct intrinsic activity, both in the liquid-electrolyte model system and in membrane electrode assemblies. However, the surface properties that contribute to the higher recorded activity of amorphous iridium oxides are not yet defined. The spectroscopic features of iridium atoms are not very sensitive to changes in the chemical environment, making structural properties difficult to elucidate. The oxygen spectrum, however, provides distinct footprints for amorphous and rutile iridium oxide materials and its features are sensitive to the surface and near-surface environment changes.
In this work, oxygen features are used to identify the surface composition of five commercially available materials consisting of amorphous, rutile, or mixed phases. The spectra of the amorphous (IrOx) and rutile (IrO2) structures present distinct features that are associated with chemical moieties identified using soft X-ray adsorption spectroscopy (1). A peak-fitting model is developed to analyze the X-ray photoelectron spectra (XPS) of the oxygen 1s orbitals. This model is used in this work to characterize and understand the modifications of the iridium oxide surfaces upon surface activation.
During the electrochemical activation of these catalysts, different surface modifications occur depending on the structure of the pristine material. Such surface evolution, which can occur during the first cycles of polarization, renders the rational design of highly active/durable materials difficult. The analysis of the superfine O1s XPS spectra at different stages of activation allows us to understand the structural evolutions leading to activity differences. This work intends to provide sufficient insights for the identification of the intermediate structures responsible for the reactivity and stability of OER catalysts.
(1) Mom, R. V.; Falling, L. J.; Kasian, O.; Algara-Siller, G.; Teschner, D.; Crabtree, R. H.; Knop-Gericke, A.; Mayrhofer, K. J. J.; Velasco-Vélez, J.-J.; Jones, T. E. Operando Structure–Activity–Stability Relationship of Iridium Oxides during the Oxygen Evolution Reaction. ACS Catal.
2022, 12 (9), 5174–5184. https://doi.org/10.1021/acscatal.1c05951.

Figure 1
A Need for Speed: Characterizing Fast Charging Failure Mechanisms in Lithium-Ion Batteries (LIBs) Using X-Ray Microtomography (XRM)
Authors: Bowen Michael 
Published: December 2024

The charging rate of traditional lithium-ion batteries is severely limited by a process known as lithium plating, whereby the rate of oxidation of lithium at the positive electrode exceeds the rate of lithium intercalation into the negative electrode active material, leading lithium ions to preferentially reduce and subsequently deposit as lithium metal at the surface of the material. Such plating further slows intercalation, causing an exponential buildup of metal at the electrode interface to the severe detriment of the system’s long-term cyclability, stability, and safety due to the formation of dead lithium and secondary SEI, as well as the increased risk of catastrophic shorting and thermal runaway. It is therefore imperative that the nucleation and growth pathways of lithium plating be fully understood and characterized to properly inform the development of novel, fast charge-capable lithium-ion battery designs.
This work discusses the use of X-ray microtomography to characterize both lithium plating on and lithiation within a graphite electrode at various charge rates. Due to the heterogeneity of these processes, the time and length scales at which they occur vary throughout the electrode and are heavily influenced by the current applied. For the first time ever, we are able to observe such phenomena as they occur using a method we call “rapid scan” X-ray microtomography to improve the temporal resolution of our scans and create operando, actionable datasets that capture the onset and growth of lithium plating and lithiation in three dimensions. Such insights are subsequently compared with and validated against trends observed post-fast charging using a more traditional tomographic approach.
In this manner, we observe and quantify the onset of lithium plating and its growth on both a local and global scale. We are also able to characterize and compare the primary (during-charge) and secondary (post-charge) intercalation of lithium into graphite and find that as much as 70% of plated lithium can be recovered if the system is allowed to rest for 30 minutes prior to discharge. Finally, we combine these two unique datasets to better understand the relationship between regional plating, active material lithiation, and charge rate, and how each of these components impacts the cyclability of the system as a whole.
Sr Oxide Nanoparticle Modified Co3O4 as an Active Oxygen Dissociation and Recombination Catalyst for Solid Oxide Reversible Cell
Authors: Narmandakh Khongorzul , Song Jun Tae , Watanabe Motonori , Ishihara Tatsumi 
Published: December 2024

Solid Oxide Cells, SOFC and SOEC, are attracting attention in energy conversion and storage systems due to their high efficiency and flexibility in various fuels. However, their performance is decreased by the limited reversibility of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air electrode, particularly at intermediate temperatures because of high overpotential from large activation energy. Therefore, developing an active and reversible air electrode for fast oxygen dissociation/association processes is crucially required. Conventional air electrodes often utilize Co-based perovskites (such as La0.6Sr0.4Co0.2Fe0.8O3−δ and Ba0.5Sr0.5Co0.8Fe0.2O3−δ) due to their high ionic and electronic conductivity, along with good catalytic activity. However, it has been observed that the presence of A-site oxide on the perovskite surface leads to lower catalytic activity. Recent approaches have explored surface modification through infiltration to enhance catalytic activity and stability [1-3]. This study focuses on investigating the cathodic performance of surface-modified B-site oxide, specifically Co3O4 spinel-type oxide, as a model catalyst with SrO modification. Figure 1 illustrates the image of the air electrode aimed in this study. It was found that the power density of the cells in SOFC condition increased after Sr infiltration, which is almost the same performance with SrCoO3 reference cell. Additionally, overpotential was significantly decreased due to the formation of active sites for ORR. For SOEC condition, Sr infiltrated cell reached a reasonable current density compared with bare Co3O4. Also, ohmic and polarization resistances decreased because of better oxygen evolution on the surface. It is found that interface between SrO and Co3O4 is active site for air electrode of solid oxide reversible cell, which is demonstrated by using diffusion of oxygen tracer, 18O.
References
[1] A. Ndubuisi, S. Abouali, K. Singh, and V. Thangadurai, J. Mater. Chem. A. 10, 2196 (2022).
[2] R. Vinoth Kumar, and A.P. Khandale. Renew. Sustain. Energy Rev. 156, 111985 (2022)
[3] D. Dong, L. Xiaxi, Y.L. Samson, G. Kirk, and L. Meilin. Energy Environ. Sci. 7, 552 (2014).
Acknowledgment
This study was financially supported by the New Energy and Industrial Technology Development Organization (NEDO) (No. JPNP20005).

Figure 1
In Situ Reference Electrodes in Water Electrolysis
Authors: Sherin Billie , Shinde Dipak , Smith Graham 
Published: December 2024

The production of green hydrogen using water electrolysis is set to play a vital role in the energy transition from fossil fuels to renewables. However, there is still significant opportunity to improve cell performance and consequently drive down the cost of producing low-carbon hydrogen, especially as new electrocatalysts and other components emerge. In situ reference electrodes are a tool that can be used to better understand the processes taking place within an operating electrolyzer cell. Deeper insights are provided into the processes occurring at the electrodes by enabling experiments that deconvolute the cell voltage into its various contributions and this can be used to map the potential though the thickness of the electrolyzer during operation.1 This deconvolution assists in characterizing new materials and supports optimization of materials selection for efficiency and durability in the operating environment.
This presentation will introduce recent advancements on the application of in situ reference electrodes to electrolyzers, including the design, development, and optimization of in situ reference electrodes for both alkaline and polymer electrolyte membrane water electrolyzers. The example data in Figure 1 shows 3 repeats of a deconvoluted polarization curve of an alkaline water electrolyser cell with nickel alloy electrodes on both anode and cathode, demonstrating how the technique enables a more insightful analysis of the behaviour of the cell.
1. Becker, H. et al. Energy Environ. Sci., 2022, 15, 2508-2518

Figure 1
(Invited) Laser Induced Generation of Emission and Photocurrent of GaN Nanoceramics
Authors: Strek Wieslaw , Musialek Agata , Tomala Robert , Stefanski Mariusz 
Published: December 2024

The measurements of laser induced emission (LIWE) and photocurrent (LIPC) of GaN semiconductor nanoceramics are reported. It was found that an origin of both the processes is related to the multiphoton ionization. They occur in a spot of focused laser beam irradiating a surface of ceramics. The emission and photocurrent are characterized by the excitation threshold and exponential increase of intensity. It was observed the hysteresis behavior in forward and backward measurement cycle for emission and photocurrent. A coexistence of both the effects open a possibility for applications in memory devices.
The authors would like to thank the National Science Centre, Poland for financial support (grant no. NCN 2021/40/Q/ST5/00220)
Thermally Stimulated Luminescence and Photoluminescence Properties of Dy-Doped Al2O3-SiO2 Glasses
Authors: Nishikawa Akihiro , Shiratori Daiki , Kato Takumi , Nakauchi Daisuke , Kawaguchi Noriaki , Yanagida Takayuki 
Published: December 2024

Storage-type phosphors absorb and temporarily store the energy of ionizing radiation and emit low-energy photons when an external stimulus such as heat or light is applied. Since the number of emitted photons is proportional to the energy of the absorbed ionizing radiation, it is possible to estimate the irradiated dose. For this reason, they are applied in various fields such as personal radiation dosimetry and medical imaging. Storage-type phosphors are classified according to the type of external stimulus applied: optically stimulated luminescence (OSL) and thermally stimulated luminescence (TSL) materials. The mechanisms of OSL and TSL can be explained below. When a storage-type phosphor is irradiated with ionizing radiation, a large number of carriers are generated, and these carriers are trapped in the trapping centers in the material, which assumes a metastable state. Subsequent stimulation with heat or light causes the carriers to be re-excited, resulting in luminescence. These storage-type phosphors are required to have high emission intensity, wide dynamic range, and low fading. In particular, when applied to personal dosimeters, the materials must have tissue equivalency.
Al2O3-SiO2 glasses focused on in this study have good characteristics such as high hardness, high melting point and elastic modulus, and low electric conductivity. Therefore, this glass composition has been considered for optical amplifiers and lasers. These properties are also advantageous in terms of material durability when used for dosimetry. In addition, the effective atomic number (Zeff = 11.8) of Al2O3-SiO2 glasses is close to that of human soft tissues, making it a promising storage-type phosphor for personal dosimeters. Therefore, the purpose of this study was to investigate the TSL properties of this glass system in detail and to evaluate the dose-response characteristics.
We prepared the Dy-doped 10Al2O3-90SiO2 glasses with various Dy concentrations (0.1, 0.3, 1.0, and 3.0%) by the melt-quenching method and investigated the photoluminescence (PL) and TSL properties. We measured the TSL glow curves of all samples to research the concentration dependence of Dy. As a result, all samples showed the TSL at around 200℃, and the 0.3% Dy-doped 10Al2O3-90SiO2 glass showed the highest TSL intensity. It was found that the TSL originated from the 4f–4f transition of Dy3+ by measuring the TSL spectrum. In addition, the lower detection limit of the 0.3% Dy-doped sample was at least 0.1 mGy. Other details on optical, TSL, and these characteristics changes due to Dy concentration in the glass will be presented in our presentation.
Luminescence Properties of Perovskites Doped with Lanthanides Under High-Power Excitation
Authors: Tomala Robert , Musialek Agata , Stefanski Mariusz , Goncalves J.M. , Strek Wieslaw 
Published: December 2024

Laser-induced white emission (LIWE) occurs when a material is excited with a focused infrared laser and is characterized by the emission of warm white light. Emission have a broadband character and cover visible range. It increased with a simultaneous decreasing f-f transitions. In particular the effect of excitation power density and concentration of dopants ions were investigated. The intensity of white emission was characterized by exponential dependence on excitation power density. Moreover the white emission threshold decreased with excitation photon energy. The photocurrent accompanying white emission was measured. It increased exponentially with excitation power density. The mechanism of laser induced white emission is briefly discussed in terms of multi-photon ionization and intervalence charge transfer (IVCT) mechanism. Therefore, it can be used as a new source of indoor lighting. Light parameters are similar to sunlight.
The authors would like to acknowledge National Science Centre for financial support (Grant No. NCN-2020/37/B/ST5/02399).
Αlpha-Ray Detection Properties of Spinel Single Crystals
Authors: Takebuchi Yuma , Tezuka Keitaro , Kato Takumi , Nakauchi Daisuke , Kawaguchi Noriaki , Yanagida Takayuki 
Published: December 2024

A scintillator is one of the phosphors for radiation detection. Typical application fields of scintillators are medical, security, and environmental dosimetry. In nuclear facilities, there are high doses of α-ray, and monitoring of α-ray is necessary. Up to now, Ag-doped ZnS is used for α-ray detection. Although Ag-doped ZnS has high light yield, the detection efficiency is limited because the material form is opaque polycrystal. Therefore, a novel scintillator with high transparency is required for α-ray detection. Spinel materials are one of the candidates for radiation detection because of their high radiation resistant. According to the previous study, scintillation properties of MgGa2O4 and ZnGa2O4 have been studied under γ-ray irradiation. On the other hand, these materials seem to be suitable for α-ray detection rather than γ-ray detection because of the low effective atomic number. In addition, other spinel materials also worth studying. In this study, we synthesized MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals and evaluated the optical and scintillation properties.
The starting powders were MgO, ZnO, Al2O3, Ga2O3. The powders were mixed into homogeneously and shaped into cylindrical rods by packing into balloon and applying hydrostatic pressure. Then, the rods were sintered 1400°C for 8 h in air to obtain ceramics precursor. Single crystalline samples were synthesized by the floating zone method using the ceramics precursor. For measurements, the synthesized crystals were processed to approximately 5 mm in diameter and 1 mm in thickness by cut and polishing.
The transparent and single-phase of the MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals were successfully obtained by the floating zone method. According to the total transmission spectra, the total transmittances of the crystals were 70−80% in visible region. In the X-ray-induced scintillation spectra, MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals showed a luminescence peak around 380, 400, 300, and 350 nm, respectively. The luminescence origin of each crystal was considered to be due to oxygen vacancies of the host materials. Figure 1 shows the pulse height spectra of the spinel crystals under 241Am α-ray irradiation. The spectra of a commercial Bi4Ge3O12 (BGO, 8000 ph/MeV) single crystal under 137Cs γ-ray irradiation is also shown as a reference. As shown in Figure 1, all the crystals showed a clear full energy peak. From the comparison with the peak position of BGO, the light yields of the MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals were 200, 4300, 700, 5700 ph/5.5MeV-α, respectively. The details will be discussed in the conference.

Figure 1
Electrolyte Cage Effects in Organic Electrosynthesis: Measuring and Driving Selectivity
Authors: Nguyen Zachary A , Boucher Dylan G. , McFadden Kevin , Minteer Shelley 
Published: December 2024

Electrochemical organic synthesis shows promise for the sustainable synthesis of agrochemical and pharmaceutically relevant molecules. However, the complexity of integrating organic and electrochemical methods often leads to overlooked reaction parameters. For example, electrolyte salts are used to decrease resistivity of the electrochemical cell and are traditionally viewed as benign species in electrochemical systems. However, the electroorganic literature is filled with examples in which changing the identity of the electrolyte impacts the reaction selectivity significantly, implying that these ‘benign’ molecules have overlooked chemical contributions to reactivity, such as the stabilization of critical intermediates.
Here, we explore the impact of electrolyte species on an important class of organic reactions: organic bond homolysis. In this reaction, a cage-paired radical is formed through the homolytic cleavage of a carbon bond, which then exists in a shell of solvent and solvated salts. This solvent-ion shell can stabilize this intermediate and allow for reversible bond homolysis. Such caged species are well-studied phenomena in metal-hydrogen atom transfer reactions and have been demonstrated to directly influence product selectivity in various organic reactions such as hydrogenation, isomerization, and dimerization. Here, we focus on how the lifetimes of cage-paired metal alkyl radical species are affected by common organic electrolytes and how this lifetime informs product selectivity. The lifetimes of these caged intermediates in various electrolyte conditions were examined using cyclic voltammetry, where titration studies were conducted to determine the rate of escape from the solvent-ion cage. This study provides insight into the role of common electrolyte salts on the stability of caged metal alkyl species and subsequent selectivity in organic synthetic reactions.