bluuebunny/crossref_metadata_2025_split huggingface dataset:
NiMn-Layered Double Hydroxides@Metal Anchored Nitrogen-Doped Carbon Framework As a Bifunctional Catalyst for Rechargeable Zinc-Air Batteries
Authors: Tu Ko-Fan , Yeh Che-Ning 
Published: December 2024

The rechargeable zinc-air battery (ZAB) holds promise as an energy storage system for the next generation due to its high theoretical energy density, safe aqueous electrolyte, environmental friendliness, and cost-effectiveness of zinc. However, the efficiency of ZABs is hindered by the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Noble metals such as platinum (Pt), iridium dioxide (IrO2), and ruthenium oxide (RuO2) are commonly used as advanced electrocatalyst materials. Nonetheless, their scarcity, high cost, unstable catalytic properties, and susceptibility to carbon monoxide poisoning limit the large-scale applications of ZABs.
Therefore, exploring non-noble bifunctional electrocatalysts for ZABs is crucial, with transition metals being viable alternatives. Recently, bimetallic transition metal layered double hydroxide (LDH) has emerged as a promising candidate for OER catalysts due to its high specific surface area, abundant active sites, and synergistic effects between two transition metals. However, LDH still faces challenges such as poor electrical conductivity and self-aggregation during fabrication.
In this work, we developed a three-dimensional core-shell structure, enabling the growth of LDH on nitrogen-doped porous carbon framework (N-C) materials to address these challenges. The N-C material, derived from zeolitic-imidazole framework (ZIF) material after pyrolysis, shows promise as an ORR catalyst. ZIF, a subclass of metal-organic framework (MOF), boasts high nitrogen content and inherits MOF advantages such as a high surface area, abundant active sites, and chemical stability. Furthermore, utilizing mesoporous silica as a hard template allows us to maintain the dodecahedral structure of ZIF and create mesoporous structures after annealing.
The core-shell structure developed in this study demonstrates superior OER and ORR catalytic activity, offering a promising direction for the design of bifunctional catalysts for high-performance ZABs.
Temperature and Interface Trap Effects on Hydrogen-Terminated Diamond Metal-Oxide Field-Effect Transistor (HD-MOSFET) Using Tcad Sentaurus
Authors: Alshammari Nuwayyir , Maimon Ory , Mulpuri Rao V , Li Qiliang 
Published: December 2024

Wide and ultrawide bandgap semiconductors demonstrate exceptional performance due to their large energy bandgap, which offers distinctive advantages such as enhanced efficiency, drift velocity, increased voltage blocking, and high-frequency switching. These characteristics make such semiconductors essential for advancing electronic technology. Among such materials, diamond is particularly distinguished for its wide bandgap, superior thermal conductivity, and high electron mobility. These properties enable diamond to perform exceptionally well in challenging environments where traditional materials may fail. Additionally, its ability to operate at elevated temperatures and voltages renders diamond-based devices suitable for a range of applications, including high-power electronics and high-frequency RF systems.
The hydrogen-terminated Metal-Oxide Field Effect Transistor (HD-MOSFET) is a highly promising and widely studied diamond device. In this device, hydrogen termination is used to induce a two-dimensional hole gas (2DHG) as high as 1014 cm-2, resulting in high drain current.
Our study investigates the Hydrogen-Terminated Diamond Metal-Oxide Field-Effect Transistor (HD-MOSFET) using TCAD Sentaurus to gain insights into the thermal performance and operational limits of diamond-based semiconductor devices. In this study, we examine the trapping effect and temperature-dependent behavior of the HD-MOSFET. Furthermore, our analysis compares the effects of temperature and interface traps on the threshold voltage (Vth), channel mobility (µch), and on-state resistance (RON) within a temperature range of 300 K to 500 K.
Oxygen Reduction Reaction Activity of Pt on Various Carbon Supports in OH- conducting Ionic Liquids
Authors: Fukuoka Kosuke , Yanagishita Takashi , Munakata Hirokazu 
Published: December 2024

The intermediate temperature operation above 100 °C is one of important targets of next generation fuel cell development from both points of view of the activity enhancement and carbon monoxide poisoning mitigation of catalysts. To tackle this challenge, we have synthesized and applied OH- conducting ionic liquids as new fuel cell electrolytes, in which the progress of oxygen reduction reaction (ORR) has been successfully confirmed at temperatures above 100 °C under non-humid conditions. However, there is a problem to be solved that the overpotential for ORR is high due to the strong adsorption of ionic species on Pt catalyst. In this study, the electronic state of Pt catalyst was designed by applying heterogeneous atom-doped graphene materials as catalyst supports to reduce the ORR overpotential.
A 1:1 mixture of tetrabutylphosphonium hydroxide (TBPOH) and tributylmethylphosphonium bis(trifluoromethanesulfonyl)imide (P4441TFSI) was prepared and used as OH- conducting ionic liquid. As Pt catalyst supports, reduced graphene oxide (RGO) and nitrogen-doped graphene (NG) were synthesized. The deposition of Pt catalyst on these graphene materials were carried out by a conventional reduction method of platinum chloride with ethylene glycol.
The ORR activity of Pt catalysts supported on various carbon materials was evaluated by cyclic voltammetry in O2 saturated TBPOH/ P4441TFSI at 120 °C, and the positive shift of ORR onset potential from 0.4 V to 0.6 V and then 0.7 V vs. RHE was observed by changing the support from commercial Ketjen Black to RGO and then NG, accompanied by an increase in the ORR current density. X-ray photoelectron spectroscopy (XPS) revealed that this improvement is related to the different electronic state of Pt catalyst, and it was suggested that the supports with higher electron donating properties such as NG are suitable for Pt catalyst to enhance the ORR activity.

Figure 1
Porous Nitrogen-Doped Carbon Supported Pt Nanocatalyst for Efficient Oxygen Reduction Reactions
Authors: WANG Zixin , Li Kui , Wang Xiaojing , Spendelow Jacob S. 
Published: December 2024

Oxygen reduction reaction (ORR) at catalyst surface is the key kinetic limiting step in fuel cells that influence the overall cell performance in the energy conversion process. Rational design of the carbon supports with unique morphology and controllable porosity is challenging and significant for efficient and durable oxygen reduction electrocatalysis. Nitrogen-doped carbon nanospheres with uniform size and precise control over mesopores and micropores have been derived from mussel-inspired biomimetic polydopamine through a facile colloidal synthesis method and subsequent high-temperature pyrolysis. The unique surface structure of this nitrogen-doped carbon also dictated the morphologies of the deposited platinum nanoparticles, alleviating the particle dissolution, detachment, and agglomeration issue, which are main factors for catalyst degradation in working conditions. The ORR activity and durability of this electrocatalysts were studied in both rotational disk electrode (RDE) system and membrane electrode assembly (MEA), and a detailed structure-property relationship between porosity of carbon supports, Pt morphologies and fuel cell ORR performance was uncovered. This work is informative to researchers working in electrochemical materials field for developing efficient and robust electrocatalyst supports.
Acknowledgement: This research was supported by the Hydrogen and Fuel Cell Technologies Office (HFTO), Office of Energy Efficiency and Renewable Energy, US Department of Energy (DOE) through the Million Mile Fuel Cell Truck (M2FCT) consortium, technology managers G. Kleen and D. Papageorgopoulos.
Preparation and Characterization of Platinum-Cobalt Nanosheets for Oxygen Reduction Reaction
Authors: Metawea Osama , Sugimoto Wataru 
Published: December 2024

Enhancing the efficiency of Pt-based electrocatalysts for the oxygen reduction reaction (ORR) is crucial for the broader use of polymer electrolyte fuel cells. Pt-based electrocatalysts are commonly used at the cathode side of polymer electrolyte fuel cells to facilitate the ORR, which is the most sluggish process during cell operation. Pt nanosheet prepared via topotactic reduction of platinum oxide nanosheets showed large electrochemically active surface area (ECSA)and high mass specific activity (MA).1 The addition of cobalt into the Pt nanosheet is expected to enhance and improve overall electrocatalytic performance as PtCo alloy nanoparticles are known to have higher specific activity than pure Pt. In this study, we present the synthesis and characterization of cobalt-doped platinum-oxide nanosheets ((Pt,Co)Ox NS) and their transformation into carbon-supported Pt-Co nanosheets for potential electrochemical applications.
The (Pt,Co)Ox NS colloid was obtained through exfoliation in aqueous solution by modification of our previous synthesis process.1 The results demonstrated enhanced electrocatalytic activity of the (Pt,Co)Ox NS composite compared to pure platinum-oxide nanosheets. For the pure platinum-oxide nanosheets, the ECSA was 97 m2 (g-Pt)-1. Moreover, employing the Koutecky-Levich equation, the MA was determined to be 321 A g-1 at 0.9 V vs. RHE, and the specific activity was 332 µA cm-2. For the PtCo nanosheets, the ECSA was similar at 91 m2 (g-Pt)-1. However, owing to the Co electronic effect, the specific activity rose to 576 µA cm-2, leading to an overall increase in MA to 524 A g-1 at 0.9 V vs. RHE. This improvement is attributed to the synergistic effect between cobalt and platinum, which enhances the oxygen reduction process.

Reference:

D. Takimoto, S. Toma, Y. Suda, T. Shirokura, Y. Tokura, K. Fukuda, M. Matsumoto, H. Imai, and W. Sugimoto, Nat Commun
14, 19 (2023)
(Invited) Non-PGM Catalysts for Electrochemical Energy Storage and Conversion
Authors: Kumar Kavita , Ku Yu-Ping , Pedersen Angus , Titirici Magda , Stephens Ifan , Bonnefont Antoine , Cherevko Serhiy , Dubau Laetitia , Jaouen Frederic , Maillard Frederic 
Published: December 2024

Energy storage and conversion occur through the manipulation of molecular bonds, catalyzed at electrified interfaces between an ion conductor and an electrocatalyst material within electrochemical reactors like hydrogen fuel cells or water electrolysers. Nanostructured electrode materials are essential for minimizing energy losses and maximizing atom efficiency in these reactions. They provide significant advantages in atomic dispersion, leading to enhanced energy efficiency and performance benefits.
The rapid and efficient development of new nanostructured catalysts requires in-depth knowledge of the relationships between nanostructure and their electrocatalytic performance and stability. Such relationships appear of utmost importance for the scientific community.
In this presentation, I will highlight some structure-activity-stability relationships of non-platinum group metal (PGM) nanostructured catalysts in acid and alkaline media. Examples will be devoted to elucidating the degradation mechanisms of iron-nitrogen-carbon (Fe-N-C) materials during fuel cell operation. Various conditions were investigated, including potential range, gas atmosphere, electrolyte, and temperature [1]. Several ex situ and in situ physicochemical techniques were combined to differentiate possible degradation mechanisms. Specifically, the combination of inductively coupled plasma mass spectrometry measurements with a gas diffusion electrode and microkinetic models showed a positive correlation between the metal dissolution profile and the local pH variation in the catalyst layer of Fe-N-C [2].

Acknowledgments

These studies were financed by the French National Research Agency in the frame of ANIMA (grant number n°ANR-19-CE05-0039) project and the DEEP (grant number n°ANR-21-CE05-0021) project.

References

[1] a) K. Kumar, P. Gairola, M. Lions, N. Ranjbar-Sahraie, M. Mermoux, L. Dubau, A. Zitolo, F. Jaouen, F. Maillard, ACS Catal.
2018, 8, 11264-11276; b) K. Kumar, L. Dubau, M. Mermoux, J. Li, A. Zitolo, J. Nelayah, F. Jaouen, F. Maillard, Angew. Chem.
2020, 132, 3261-3269.
[2] Pedersen A, Kumar K, Ku Y-P, Martin V, Dubau L, Teixeira Santos K, et al. ChemRxiv. 2024; doi:10.26434/chemrxiv-2024-7p3cm.
Durability and Structural Transformation of Pt Alloy Nanowires and Nanoparticles for the Oxygen Reduction Reaction in Acidic Media
Authors: Kato Masaru , Zhuang Yu , Kato Yuta , Iguchi Yoshimi , Li Tianchi , Tanioku Shinji , Yagi Ichizo 
Published: December 2024

The oxygen reduction reaction (ORR) is catalyzed at the cathode in polymer electrolyte fuel cells (PEFCs). Since the ORR is sluggish and the electrocatalytic activity of the ORR catalyst determines the overall performance of PEFCs, highly active and durable ORR electrocatalysts have been intensively studied. The combination of alloying and nanostructuring of Pt is one of the promising approaches to develop such ORR electrocatalysts. Among the Pt-based shape-controlled electrocatalysts, Pt or Pt–M alloy nanowires (M = Ni and Co) are known to exhibit high ORR activity in the half cell [1,2]. Since nanowires have larger contact areas and therefore potentially higher adhesion to the carbon support than conventional nanoparticles, Pt-based nanowires should have higher durability. However, details of the effect of durability testing (potential cycles) on the structure of nanowires remain unclear.
In this work, we report synthesis of PtNi alloy nanowires at different temperatures under different atmospheres, and their structural transformation after potential cycles. PtNi nanowires were prepared at 433 K under Ar and air [3]. The difference in atmosphere affects the presence or absence of PtNi nanoparticles with PtNi nanowires: both PtNi nanowires and nanoparticles are produced under the inert condition of Ar, whereas PtNi nanowires are exclusively produced under the oxidative condition of air. PtNi nanowires with and without PtNi nanoparticles were converted into branched nanostructures after durability tests. PtNi nanowires were also prepared at different temperatures of 433, 493 and 553 K under Ar [4]. The Ni content in the PtNi nanowires increases from <5 at.% up to about 15 at.% with increasing synthesis temperature. The number of PtNi nanoparticles also decreases with increasing synthesis temperature. The PtNi nanowires in the co-presence of PtNi nanoparticles prepared at 493 K gave highly durable beads-on-nanowires with the Pt skin via Ostwald ripening of coexisting PtNi nanoparticles. This structural transformation is coupled with changes in the surface electronic structure, confirmed by in situ X-ray absorption spectroscopy. Understanding such a structural transformation will help us to design and develop highly durable Pt alloy nanostructured electrocatalysts for the ORR.
References.
[1] M. Li et al., Science, 354, 1414 (2016).
[2] Z. Zhao et al., Adv. Mater.,31, 1808115 (2019).
[3] M. Kato, Y. Iguchi, T. Li, Y. Kato, Y. Zhuang, K. Higashi, T. Uruga, T. Saida, K. Miyabayashi, I. Yagi, ACS Catal., 12, 259 (2022).
[4] Y. Zhuang, Y. Iguchi, T. Li, Y. Kato, M. Kato, Y. A. Hutapea, A. Hayashi, T. Watanabe, I. Yagi, ACS Catal., 14, 1750 (2024).
Oxygen Evolution Reaction Activity and Stability of Copper and/or Manganese Cobalt Spinels
Authors: Liu Christopher Pantayatiwong , Roiron Camille , Atanassov Plamen 
Published: December 2024

Gigawatt-scale hydrogen production using proton exchange membrane water electrolyzers may be limited by the availability of iridium (oxide), the current state-of-the-art catalyst for the oxygen evolution reaction (OER) in acid [1]. And yet, iridium-free catalysts have struggled to meet both the activity and stability of iridium oxide, much in part due to the thermodynamic instability of most transition metals in acidic OER conditions. Recently, though, reports of Cu, Co, and/or Mn containing iridium-free spinels have demonstrated promising performance [2–4].
Notwithstanding, the degradation mechanisms of these spinel-type catalysts are not well understood, as well as design strategies to mitigate the degradation. To explore these topics, four iridium-free, spinel-type catalysts were synthesized, characterized, and assessed for activity and stability: CuCo2O4, MnCo2O4, Cu0.5Mn0.5Co2O4, and Co3O4. The synthetic route (sacrificial support method) was built upon a previous study on CuCo2O4 for the alkaline OER by our group [5]. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy were performed to investigate the crystal structure (see Figure 1A), surface oxidation state, and morphology of the catalysts, respectively, both before and after accelerated stress tests (ASTs). Additionally, electrolyte samples were taken before and after ASTs to quantify catalyst dissolution.
From Figure 1B, linear sweep voltammetry measurements revealed that the mixed metal oxides all demonstrated enhanced mass OER activity compared to the monometallic Co3O4. From chronoamperometry measurements at 1.8 V vs. RHE in 0.1 M HClO4 , the mixed metal oxide catalysts lasted over 20 hours before reaching approx. 10% of the initial activity. Stability testing in a membrane electrode assembly (750 mA cm–2 hold, Nafion 212) demonstrated over 500 hours of operation at approx. 2.6 V. Operando X-ray photoelectron spectroscopy (XPS) and near edge X-ray adsorption fine structure (NEXAFS) experiments, along with in-situ inductively coupled plasma mass spectrometry (ICP-MS) measurements, are planned to complement the pre- and post-AST ex-situ catalyst characterization. Although these materials have yet to reach the activity and stability of iridium oxide, they nonetheless provide insights on a promising family of iridium-free catalysts and their development.

Acknowledgements

This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. (DGE-1839285). Any opinion, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Figure 1
Bubble Dynamics at Single-Phase Nickel Nitride and Sulfide for Hydrogen Evolution Reaction
Authors: Tyagi Chinkit , Fabre Bruno , Lagrost Corinne , Tessier Franck , Jullien Marie-Caroline , Bouquet Valérie 
Published: December 2024

Hydrogen (H2) is considered a clean and sustainable alternative energy carrier to fossil fuels for meeting future energy demands.1 Electrocatalytic water splitting is a promising approach to producing eco-friendly H2 involving a hydrogen evolution reaction (HER) at the cathode and an oxygen evolution reaction (OER) at the anode.2 However, during these electrochemical gas evolution reactions, gas bubbles evolving at the surface of the electrocatalyst may result in undesired blockage of active sites and can influence the performance of the electrocatalytic process.3

In this study, we optimized the direct growth of single-phase nickel sulfide and nitride (Ni3S2@NF and Ni3N@NF) on metallic nickel foil (NF) and investigated the influence of surface hydrophilicity or hydrophobicity on electrochemical HER through in situ hydrogen bubble dynamics. Contact angle measurements revealed that metallic NF, Ni3S2@NF, and Ni3N@NF electrodes followed a trend of decreasing contact angle in an alkaline solution, indicating that Ni3N@NF exhibited the highest hydrophilicity/aerophobicity.4

In situ bubble visualization demonstrated that hydrophilic/aerophobic Ni3N@NF led to smaller and faster bubble departure, offering more active sites and a lower overpotential. Conversely, decreasing hydrophilicity or aerophobicity resulted in larger bubbles and longer retention times, leading to the unwanted blockage of the active sites and requiring high overpotential for HER. This highlights the significant impact of surface-wetting properties and hydrophilicity on electron and mass transfer during hydrogen generation, particularly at higher current densities.
References

Lewis, N. S.; Nocera, D. G. Natl. Acad. Sci. U. S. A. 2006, 103, 15729.

Turner, J. A. Science 2004, 305, 972.

Angulo, A.; van der Linde, P.; Gardeniers, H.; Modestino, M.; Fernández Rivas, D. Joule 2020, 4, 555.

Tyagi, C.; Fabre, B.; Jullien, M.-C.; Bouquet, V.; Tessier, F. submitted.

Figure 1
Reproducibility in Electrocatalysis
Authors: Hausmann Jan Niklas , Menezes Prashanth W. 
Published: December 2024

A bright future for electrochemistry is anticipated due to its crucial role in the decarbonization of our industry and energy economy. In this regard, the number of electrochemists, their publications, the taxpayers' funding, and the number of applied materials has grown substantially in the last decade. This growth in interest has also led to an increase in the complexity of the reported systems, e.g., heterostructures with multiple interfaces.[1] However, studies attempting to reproduce known literature procedures often find different values for activity metrics, such as overpotentials, capacities, or long-term stabilities.[2] Furthermore, in my personal experience, I have not met an electrochemist who would be surprised when a student reports that he could not reproduce the outstanding performance of a recent report. Non-reproducibility is a substantial problem and threatens the foundation of science.[3]

We have performed a study among more than ten different groups across the globe. In this study, three electrode fabrication procedures (electrodeposition, precipitation followed by Nafion-binder-based powder deposition, hydrothermal modification of a metal foam) have been performed three times by all these groups using the same chemicals. A strict and uniform test protocol is applied to obtain activity metrics (overpotential, Tafel slope, charge transfer resistance...) of these electrodes for the electrocatalytic oxygen evolution reaction. Based on this tremendous set of data (>100 electrodes tested under the same conditions), we discuss the following questions:

How reproducible are our current electrochemical methods?

Which factors influence reproducibility?

How can we improve reproducibility?

Literature:
[1] Hausmann, J. N. & Menezes, P. W. A rising mismatch between system complexity, characterization, and theory in electrocatalysis: challenges and solutions. Appl. Catal. B Environ.
2024, 342, 123447.
[2] Peugeot, A. et al. Benchmarking of oxygen evolution catalysts on porous nickel supports. Joule
2021, 5, 1281–1300.
[3] Munafò, M. R. et al. A manifesto for reproducible science. Nat. Hum. Behav.
2017, 1, 0021.