bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) review of Broadband Dielectric Spectroscopic Detection of Volatile Organic Compounds with Surface Anchored Organic Frameworks As Solid-State Sensor Materials
Authors: Amoah Papa Kojo , Baumgart Helmut , Redel Engelbert , Hassan Zeinab , Franklin Rhonda R , Obeng Yaw 
Published: December 2024

Volatile Organic Compounds (VOCs) encompass a very wide range of organic compounds characterized by high vapor pressure at lower temperatures, which gives them significant volatility already at room temperatures. They are present in the living and work environments. Long-term indoor exposure to VOCs can cause fatigue, headache, nausea, eye, nose, and throat irritation in sensitive persons, but also damage the central nervous system and other organs. Because of their widespread occurrence in our environment, there is a need for good detectors and sensors for VOCs. We have investigated the perturbation of the physico-chemical the properties of Zinc Oxide (ZnO) and Metal-Organic Frameworks (MOFs) in the presence of VOCs, and developed a novel approach for the detection of such VOCs utilizing Broadband Dielectric Spectroscopy (BDS) techniques.
In this talk, we will review the current state-of-the-art in MOF sensing research to provide a context for the novel BDS metrology we have developed, discuss our effort to elucidate the sensing mechanisms of HKUST-1 MOF films with BDS, and showcase the capabilities of BDS for metal-oxide sensing research advancement. Specifically, we will focus on the use of surface anchored MOF (SURMOF)– as opposed to free running powdery MOFs, as sensing agents. Our results show that the SURMOF sensing agent is stable, more robust, and more sensitive in detecting VOCs, than traditional metal oxide (MOS) agents even at temperatures well below 100 °C.
Electrochromism of Redox-Active Ionic Liquids and the Kinetics of the Colorations
Authors: Tahara Hironobu , Murakami Hiroto 
Published: December 2024

Electrochromic (EC) devices have been gaining attention for display, electronic paper, and smart windows because of the low-power consumption, low-voltage drive, and memory effect of the colored state holding sharp contrast. They could be useful for the intended usage, which organic light emitting diode and liquid crystal display do not cover.
The minimum components of EC devices are (i) redox-active EC material for a transparent electrode of interest, (ii) supporting electrolyte, (iii) medium (solvent), and (iv) charge-compensating (charge-balancing) redox material for another electrode. The medium (solvent) is required for electrolytes, which provide electric conductivity to the device. However, it is difficult to solve the problems of solvent evaporation and leakage of the electrolyte solution from the device. Recently, ionic liquids (ILs) are the focus of extensive investigations for electrochemical devices due to their non-volatility, moderate viscosity, and chemical stability. ILs can play roles of both solvent and supporting electrolytes. We have been focused on ILs as a designable liquid material with the above useful properties and developed electrochromic redox-active ionic liquids (RAILs).
In RAILs, either or both constituent ions are redox-active. RAILs are a new class of ILs, which are non-volatile, electro-conductive, and viscous liquid materials. In addition, RAILs consist of concentrated redox-active ions, resulting in large redox density. In the case of RAILs with electrochromic ions, which are electrochromic RAILs (EC-RAILs), the concentrated electrochromic species give a large light absorption resulting in a very thin device thickness. The non-volatility and chemical stability provide the long-term durability of the EC devices. EC-RAILs play the roles of (i)-(iv) required in EC devices. In this study, we developed EC-RAILs, the coloration process by the voltage control, and their application to the EC devices without using solvents and supporting electrolytes. Because of the concentrated redox species and absence of the supporting electrolyte, the resistance of the EC cells could be dominant for the coloration kinetics.
In this study, we have analyzed the electrode kinetics of the EC device composed of pure EC-RAILs.
Electrochromism of Redox-Active Ionic Liquids Based on Pyridinium Derivatives
Authors: Murakami Hiroto , Tahara Hironobu 
Published: December 2024

Electrochromism is a phenomenon in which reversible color change occurs by redox reaction and devices with such characteristics are called electrochromic (EC) devices. The EC devices are often composed of EC materials, compensators for the reaction charge, electrolytes, solvents, and electrodes. Such EC devices, however, contain potential issues such as solvent volatilization and damage caused by physical cracks.
By the way, ionic liquids (IL) are non-volatile, flame retardant, chemically stable, and possess high ionic conductivity. In addition, ILs play double roles as electrolytes and solvents. Therefore, fabricating all components of the EC device using IL leads to not only clearing up the issues at once but also the development of the eco-friendly one.
In this work, we have fabricated two types of EC devices. In this work, we have fabricated two types of EC devices. One is an all-in-one type that consists of only ferrocene (Fc)-viologen (V)-linked IL.1 The other is a composite type that is composed of an Fc IL and V IL without any additives: solvent, supporting, and electrolyte.2 As a result, both EC devices showed good EC performance. The efficiency of the former and later devices were 70 and 91.4 cm2 C-1 at 1.0 V, respectively; the EC process was stable even after over 10 000 potential cycles for the former device and 13 000 ones for the latter device.
In this presentation, we also describe the synthesis of ILs and their electrochemistry in detail.
Toward a Fundamental Understanding of Solid-Solid Interfaces in Hydrogen Fuel Cells and Water Electrolysis through First-Principles Based Modeling
Authors: Zeng Zhenhua 
Published: December 2024

To achieve Net-Zero Emissions by 2050, hydrogen and hydrogen fuel cells will play a significant role in powering vehicles. In this talk, I will show, through first-principles-based modeling, how to achieve rigorous modeling and a fundamental understanding of the solid-solid interface for the oxygen reduction reaction in hydrogen fuel cells and the hydrogen evolution and oxygen evolution reactions in water electrolysis. I will further show how the fundamental understanding paves the way toward developing both model and industrial electrocatalysts with significantly improved performance. Specifically, I will introduce the following three topics.
[1] metal-metal interfaces: strain generation and strain tuning of epitaxial, stepped and free-standing platinum group metals for the oxygen reduction reaction in hydrogen fuel cells. (1, 2)
[2] metal-oxide interfaces: stability and activity of monolayer oxide/Pt interface toward improving the hydrogen evolution reaction in the alkaline electrolysis.(3)
[3] oxide-oxide interfaces: self-consistent modeling of active phases, reaction centers, and catalytic mechanisms of Ni- and Co-based layered double hydroxides for the oxygen evolution reaction in the alkaline electrolysis.(4-6)
References:

L. Wang, Z. Zeng, W. Gao, T. Maxson, D. Raciti, M. Giroux, X. Pan, C. Wang, J. Greeley, Tunable intrinsic strain in two-dimensional transition metal electrocatalysts. Science
363, 870-874 (2019).

G. Liu, A. J. Shih, M. T. M. Koper, J. Greeley, Z. Zeng, Site-specific reactivity of stepped Pt surfaces driven by stress release. Nature, (2024).

Z. Zeng, K.-C. Chang, J. Kubal, N. M. Markovic, J. Greeley, Stabilization of ultrathin (hydroxy)oxide films on transition metal substrates for electrochemical energy conversion. Nature Energy
2, 17070 (2017).

F. Dionigi, Z. Zeng, I. Sinev, T. Merzdorf, S. Deshpande, M. B. Lopez, S. Kunze, I. Zegkinoglou, H. Sarodnik, D. Fan, A. Bergmann, J. Drnec, J. F. d. Araujo, M. Gliech, D. Teschner, J. Zhu, W.-X. Li, J. Greeley, B. R. Cuenya, P. Strasser, In-situ structure and catalytic mechanism of NiFe and CoFe layered double hydroxides during oxygen evolution. Nature Communications
11, 2522 (2020).

F. Dionigi, J. Zhu, Z. Zeng, T. Merzdorf, H. Sarodnik, M. Gliech, L. Pan, W.-X. Li, J. Greeley, P. Strasser, Intrinsic Electrocatalytic Activity for Oxygen Evolution of Crystalline 3d-Transition Metal Layered Double Hydroxides. Angew. Chem., Int. Ed.
60, 14446-14457 (2021).

Q. Wu, J. Liang, M. Xiao, C. Long, L. Li, Z. Zeng, A. Mavrič, X. Zheng, J. Zhu, H.-W. Liang, H. Liu, M. Valant, W. Wang, Z. Lv, J. Li, C. Cui, Non-covalent ligand-oxide interaction promotes oxygen evolution. Nature Communications
14, 997 (2023).
Active Sites for ORR on Pt in PEM Fuel Cells: A DFT Perspective
Authors: Zeng Zhenhua 
Published: December 2024

For ORR on Pt, the classic model categorizes active sites based on surface motifs, such as terraces and steps. However, this simplistic approach often leads to orders of magnitude errors in catalyst activity predictions and qualitative uncertainties of active sites, thus limiting opportunities for catalyst design. Using stepped Pt(111) surfaces and ORR as examples, we will illustrate that the root cause of larger errors and uncertainties is such a simplified categorization overlooks atomic site-specific reactivity driven by surface stress release. Specifically, we will show how surface stress release at steps introduces inhomogeneous strain fields, resulting in distinct electronic structures and reactivity for terrace atoms with identical local coordination. This phenomenon leads to a cluster of active sites flanking both sides of the step edge. We will demonstrate strategies to enhance ORR activity in low temperature (<100 °C) PEM fuel cells by leveraging this effect, such as varying terrace widths,[1] adjusting the thickness of 2D nanosheets[2] or controlling external stress.[3]

For ORR in high tempatature (>100°C) PEM fuel cells, we found that, in contrast to ORR under hydrous conditions, (111) terrace sites are not active for ORR under anhydrous conditions, because of weakened binding of ORR intermediates induced by O* accumulation on the surface. On the other hand, step edges, which are generally not active for ORR under hydrous conditions, are predicted to be the active sites for ORR under anhydrous conditions. Among them, (110) type step edge with a unique configuration of accumulated O stabilizes O2 adsorption and facilitates O2 dissociation, which lead an overpotential <0.4 V. To improve ORR catalysts in high‐temperature PEMFCs, it is desirable to maximize (110) step edge sites that present between two (111) facets of nanoparticles.[4]

[1] G. Liu, A. J. Shih, H. Deng, K. Ojha, X. Chen, M. Luo, I. T. McCrum, M. T. M. Koper, J. Greeley, Z. Zeng, Nature
2024, 626, 1005-1010.
[2] L. Wang, Z. Zeng, W. Gao, T. Maxson, D. Raciti, M. Giroux, X. Pan, C. Wang, J. Greeley, Science
2019, 363, 870-874.
[3] K. J. Sawant, Z. Zeng, J. P. Greeley, Angew. Chem., Int. Ed.
2024, 63, e202312747.
[4] G. Liu, H. Deng, J. Greeley, Z. Zeng, Chinese Journal of Catalysis
2022, 43, 3126-3133.
Mechanistic Insights into the Formation and Growth of Supported Metal Nanoparticles By an Identical-Location Synthesis Approach
Authors: Seidl Lisa Maria , Hu Yang , Li Qingfeng 
Published: December 2024

Electrocatalysts are key materials for the development of a wide range of renewable energy technologies, such as fuel cells, electrolyzers, and P2X devices. Often the best catalysts in terms of the activity and stability take the form of well-dispersed precious metal particles supported on a highly durable and conductive substrate. In particular, for high-temperature proton-exchange membrane fuel cells, the anode catalyst most desired by the industry is Pt-based nanoparticles of 4-5 nm with a high metal loading (e.g. 50 wt%) well dispersed on a graphitized carbon support. Unfortunately, synthesis of such catalysts on a sufficiently large scale has rarely been achieved.
Recently, our group has developed a solid-state chemical process for the synthesis of supported electrocatalysts.1, 2 Regarding the particle formation mechanism, the classical nucleation theory provides a fundamental basis for understanding the synthesis process, but it is insufficient to predict the detailed mechanism when synthesis precursors of specific structures are involved. Herein, we report our recent progress in understanding the key processes governing the formation and growth of Pt nanoparticles on different carbon supports, through investigations using an identical-location synthesis approach. Figure 1 shows the TEM images of a synthesis precursor before and after the reduction step. Based on the insights gained, we have attempted to synthesize the much-anticipated catalyst, graphitized carbon supported Pt-based nanoparticles. We believe that the mechanistic insights obtained and the syntheses demonstrated will provide important guidance for the synthesis of various types of supported catalysts. Furthermore, we expect this method to be suitable for the synthesis of catalysts on a larger scale.
References:

Y. Hu; Jensen, J. O.; Norby, P.; Cleemann, L. N.; Yang, F.; Li, Q., Mechanistic Insights into the Synthesis of Platinum–Rare Earth Metal Nanoalloys by a Solid-State Chemical Route. Chemistry of Materials
2021,
33 (2), 535-546.

Y. Hu; Jensen, J. O.; Cleemann, L. N.; Brandes, B. A.; Li, Q., Synthesis of Pt–Rare Earth Metal Nanoalloys. Journal of the American Chemical Society
2020,
142 (2), 953-961.

Figure 1: IL-TEM images of the synthesis precursors before (left) and after (right) of the high-temperature reduction.

Figure 1
Dihydroxyl Additives for Enhancing Activity and Durability of Pt/C Catalysts.
Authors: Agarwal Tanya , Komini Babu Siddharth , Li Kui , Borup Rod L. 
Published: December 2024

Fuel cells are especially attractive as a decarbonization strategy for heavy duty transportation sector. However, the durability and cost of the fuel cell components remains a major barrier for market penetration. Expensive platinum based catalysts, represent a significant portion of this challenge. Therefore, effort to enhance their durability and performance, without increasing the loading, could make a significant advancement towards commercial viability. In this study, we investigated the incorporation of dihydroxyl additive, ellagic acid (EA), in cathode catalyst layers to improve the performance and durability of the catalysts. Our observation revealed that incorporation of EA into cathode catalyst layer led to an increase in mass activity when used with a Pt catalyst supported on either vulcan and high surface area (HSC) carbon support. Increase in the overall conductivity of the catalyst layers due to the hydrophilic nature of the additive could be responsible for improved performance. Decrease in the catalyst activity inhibition by the ionomer adsorption of the platinum surfaces could also result in improved catalytic activity.
Further increase in mass activity with the HSC can be achieved by the optimizing the solvent used for ink preparation for enhanced interaction of EA with the platinum inside the pores and not just the surface platinum particles. We also find enhanced durability of both Pt/Vulcan and Pt/HSC catalyst with the chosen additive in accelerated stress tests. The probable reasons for this behavior will be discussed.

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) consortia, technology managers G. Kleen and D. Papageorgopoulos.
Expanding the Scope of ZIF-Derived Carbons Towards Tailored Architectures and Compositions
Authors: Pappas Nina , Ojo Alaba Upe , Chen Kate , Dolgopolova Ekaterina , Wang Xiaojing , Spendelow Jacob S. 
Published: December 2024

Proton exchange membrane fuel cells (PEMFCs) represent a promising technology for clean energy conversion. The key chemical transformation within a fuel cell is conducted by catalyst nanoparticles tethered to a carbon support. Although the carbon support plays a critical role in maximizing the performance and durability of the catalyst nanoparticles and mass transport, predictably tuning the chemical environment and pore architecture of the carbon support remains a challenge. Metal–organic frameworks are a class of crystalline porous coordination polymers known for their structural and chemical tunability. Recently, metal–organic frameworks (MOFs), almost exclusively zeolitic imidazolate framework-8 (ZIF-8), have been used as precursors to generate carbon supports where the MOF architecture serves as a template to generate the carbon skeleton. As a result, these materials have an improved homogeneous porous landscape and, encouragingly, superior PEMFCs performance and durability. Herein, we leverage the vast library of MOFs and report design principles for generating precisely tuned carbon support architectures through systematic changes to the structure and chemical composition of MOFs. Advanced fuel cell testing of PEMFCs featuring these novel carbon architectures offers fine level insight into the effects of pore size, connectivity and chemistry on the performance of PEMFCs.
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.
Advanced ORR Catalysts Based on Intermetallic Nanoparticles and Metal-Organic Frameworks
Authors: Chen Kate , Li Kui , Wang Xiaojing , Wu Gang , Spendelow Jacob S. 
Published: December 2024

Metal-organic frameworks (MOFs) based catalysts are emerging as highly promising enablers for high-performance and durable fuel cells. Our novel PtCo catalyst, supported by porous carbon derived from the pyrolysis of zeolitic imidazolate framework-8 (ZIF-8), dubbed PtCo/ZIF8, demonstrates superior performance and robustness during fuel cell operations. Tested under the Million Mile Fuel Cell Truck Consortium (M2FCT) conditions—250 kPa, 85% relative humidity, 90 °C cell temperature, and 15% oxygen—the PtCo/CZIF8 consistently outperformed commercial catalysts at critical operating voltages of 0.7 V and above. Notably, it achieved a current density of 1.43 A/cm2 at 0.7 V after enduring 90,000 accelerated stress test (AST) cycles, surpassing the M2FCT's end-of-life target of over 1.07 A/cm2. Furthermore, the catalyst showed a high mass activity of 0.87 A/mgPt initially, which only declined to 0.59 A/mgPt by the end-of-life test , indicating a 32% loss. In terms of electrochemical surface area (ECSA), the PtCo/CZIF8 maintained about 64% of its initial ECSA after the 90,000 AST cycles, well within the M2FCT’s protocol of less than 40% ECSA loss1. These results establish MOF-based catalysts as front-runners for fuel cell commercialization and are crucial for global efforts to reduce greenhouse gas emissions.
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.
References:
1.https://millionmilefuelcelltruck.org/ast-protocols
Perovskites As Oxygen Evolution Reaction Catalysts for Alkaline Electrolysis: A Stable Alternative?
Authors: Buchauer Fabian Luca , Simonsen Soren Bredmose , Chatzichristodoulou Christodoulos 
Published: December 2024

The sluggish nature of the Oxygen Evolution Reaction (OER) is responsible for a large efficiency penalty in alkaline electrolysis (AEL), with intensive research targeting more active and stable catalysts. Catalyst testing is typically carried out in RDE setups under mild conditions. Such tests are useful for evaluating the catalytic activity, but the results are seldom inter-comparable due to differences in electrode fabrication, microstructure, catalyst surface area, and test conditions. Furthermore, the material activity and stability at mild conditions does not represent the one at industrial conditions. Thus, testing the materials at industrial application conditions is crucial, i.e. at higher temperatures, e.g. 60-100°C, at concentrated KOH, e.g. 6-10M, and for longer times.
Perovskites are an exciting group of materials as OER catalysts due to their reported high catalytic activities [1], and their tunable properties, allowing ample room for optimization and use of abundant elements. Even though many studies report the stability of perovskites under mild conditions and for durations of up to 2000h [2], the stability at industrial conditions is still in question. In this study, we tested the catalytic activity of La-based perovskites and others at industrial conditions. For better comparability, the tests are carried out on dense and polished pelettes with a well-defined surface area. Post-mortem analysis shows that the most researched materials are unstable at industrial conditions. However, one candidate showed excellent stability far beyond the commercial operation window, with only minor signs of degradation after 200h at 150°C, while possessing excellent intrinsic activity, with an overpotential of 240mV at 10mA/cm2
ECSA.
Furthermore, perovskites are an excellent host for exsolution, which is the partial decomposition of the host material to form well-dispersed and anchored nanoparticles on the surface of the host. We have used the exsolution process to enhance the catalytic activity even further, and short-term stability tests confirm the presence of the exsolved particles after several hours of operation at industrial conditions. To the best of our knowledge, this study shows the first report of exsolved catalysts under industrial operating conditions.
[1] Liu, L. B., Yi, C., Mi, H. C., Zhang, S. L., Fu, X. Z., Luo, J. L., & Liu, S. (2024). Perovskite Oxides Toward Oxygen Evolution Reaction: Intellectual Design Strategies, Properties and Perspectives. In Electrochemical Energy Reviews (Vol. 7, Issue 1). Springer Nature Singapore. https://doi.org/10.1007/s41918-023-00209-2
[2] Jo, H., Yang, Y., Seong, A., Jeong, D., Kim, J., Joo, S. H., Kim, Y. J., Zhang, L., Liu, Z., Wang, J. Q., Kwak, S. K., & Kim, G. (2022). Promotion of the oxygen evolution reaction: Via the reconstructed active phase of perovskite oxide. Journal of Materials Chemistry A, 10(5), 2271–2279.

Figure 1