bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrospun Sulfonated Silica/P(VDF-TrFE)-Based Composite Membranes for PEM Fuel Cells
Authors: Yarar Kaplan Begüm , Rajabalizadeh mojarrad Naeimeh , Kırlıoğlu Ahmet Can , Alkan Gursel Selmiye 
Published: February 2024

Nafion® membranes are the most widely used commercially available membranes for PEM fuel cells due to their good chemical and mechanical stability as well as high ionic conductivity at fully humidified conditions. However, their high cost and inadequate conductivity at lower humidity levels can be addressed as the main drawbacks of Nafion® membranes which needs to be overcome. In this regard new strategies such as complete replacement of these membranes with alternative cost-effective membranes or modifying their properties via synthesizing of Nafion® containing composite membranes by incorporation of some inorganic additives such as silica were extensively investigated previously [1].
In this study, we developed two types of electrospun composite membranes: in the first route: membranes were prepared with using P(VDF-TrFE) or PVDF as carrier polymers which are decorated with sulfonated silica (S-SiO2) nanoparticles, as a proton conducting additive. Here S-SiO2 nanoparticles were synthesized via hydrothermal method, then these nanoparticles were added to the electrospinning solutions to prepare the hybrid membranes. The effect of S-SiO2 amount in final properties of these membranes were investigated via preparing samples with three different S-SiO2/ carrier polymer ratios [2]. In the second approach, a combination of sol-gel and dual electrospinning methods were employed to fabricate proton conducting membranes comprising sulfonated silica network, Nafion®, and PVDF or P(VDF-TrFE) as the carrier polymers. For this purpose, the obtained S-SiO2 network via sol-gel method was incorporated into the Nafion®/carrier polymer mixed fibrous-mats during dual electrospinning process [3]. In both approaches after electrospinning all electrospun mats were transformed to compact membranes via hot-pressing process. Then fabricated mats and compact membranes, were characterized by various techniques including FTIR, XPS, SEM, TEM, ionic conductivity, ion exchange capacity (IEC), water uptake and mechanical tests. Finally, membrane-electrode-assemblies (MEAs) were prepared via composite electrospun membranes and fuel cell performance tests were performed. The results showed an enhancement in ionic conductivity for both set of membranes (102 and 132 mS/cm) compared to commercial Nafion® membranes at the same conditions. Moreover, the fuel cell test exhibited that presence of sulfonated silica in the composite membranes improved the performance at lower humidity conditions (344 mW/cm2 at 60% RH) due to enhanced water retention ability of the resultant composite membranes.
References:
[1] Shang Z., Wycisk R., Pintauro P., Energies, 14(20), 6709, (2021).
[2] Rajabalizadeh Mojarrad N., Iskandarani, B., Taşdemir, A., Yürüm, A., Gürsel, S.A., Yarar Kaplan, B., Int J Hydrogen Energy, 46(25), 13583-13593, (2021).
[3] Rajabalizadeh Mojarrad N., Kırlıoğlu A., Yarar Kaplan, B., J Solid State Ionics, 392, 116152, (2023).
(Invited) Molecular Insights into Water Structure and Proton Transfer at the Interfaces in Bipolar AEM/PEM Membranes
Authors: Paddison Stephen J. 
Published: February 2024

Bipolar membranes (BPMs) are polymeric membranes composed of an acidic proton exchange membrane (PEM) and an alkaline anion exchange membrane (AEM). Bipolar membranes are operated in two different configurations, forward bias and reverse bias, based on the orientation of membranes and electrodes, when the cathode faces the PEM, it is operated in a reverse bias configuration. In reverse bias BPMs facilitates the dissociation of water at the interface of its junction. This unique feature makes it attractive to many industrial applications, including chemical industries, energy conversion and storage, environmental protection, and food processing. It was determined that the rate of water dissociation at the interface of a bipolar membrane increases with the addition of a weak acidic head group material, which acts as the catalyst for the water dissociation reaction and thus referred as the catalyst layer. BPMs have a better ion transport framework because of the amphiphilic nature of all three layers, resulting in well-connected water channels. Hence it is crucial to understand the interaction of water molecules with the functional groups at the molecular level and the morphology at mesoscale to understand the water aggregation and phase separation which helps in the asymmetric transport of proton and hydroxide ions through PEM and AEM respectively.
This talk will communicate our efforts to undertake a multiscale approach involving both electronic structure calculations and mesoscale simulations to elucidate: (1) water interaction of water with the headgroups; proton transfer, and (2) connectivity of a TMA AEM, a PFSA PEM, and a phosphonic acid-based catalyst.
Fundamentals of Gas Permeation in PEM Water Electrolyzers Operated at High Pressures
Authors: Khedekar Kaustubh , Li Kui , Gebhardt Ryan , Park Andrew , Borup Rod L. , Komini Babu Siddharth 
Published: February 2024

The high cost of clean hydrogen (H2) remains a major hurdle to drive large scale adoption and achieve zero emission goals. For large scale deployment using low cost renewable electricity, polymer electrolyte membrane water electrolyzers (PEMWEs) show high potential based on their high faradaic efficiency and high operating current density. Operation of PEMWEs at high differential pressures can significantly reduce the per kilogram price of H2 and increase the overall energy efficiency while also eliminating the necessity to compress H2 during storage and transportation.1 Thinner membranes reduce the voltage losses from ohmic resistance and achieve high faradaic efficiencies. However, a higher crossover of hydrogen from the cathode through the membrane to the anode is observed for thinner membranes at high cathode operating pressures. As Ir/IrO2 (anode catalyst) is inefficient in oxidizing H2
1, this increased crossover of H2 not only reduces the PEMWE efficiency but also results in formation of an explosive gas mixture. Some initial studies also suggest critical effect of crossover H2 on durability of the anode catalyst. Addition of a gas recombination catalyst (GRC) in the membrane is a highly useful strategy to oxidize permeating H2 and prevent the formation of such explosive gas mixtures. Despite the importance, fundamentals of gas recombination reaction mechanism along with the effects of GRC and its properties on it is not well established.
In this study, effect of the GRC and its properties (loading, particle size, distribution, and location) on H2 permeation will be elucidated using a high pressure (up to 30 bar) electrolyzer setup coupled with online gas chromatography (Figure 1). The role of H2 and O2 partial pressures and operating current densities (simulated by varying the flow rates) will also be closely examined. Effects caused by the addition of anode and cathode catalyst layers on H2 permeation will also be presented in addition to long-term membrane durability results.
Figure 1. Decreased H2 permeation rate observed with GRC (Membrane A) at different cathode (H2) operating pressures at 80 °C using ex-situ electrolyzer setup. Deactivation of the GRC reaction is observed when switching the anode gas from O2 to N2.

Figure 1
Electrochemical Top-Down Synthesis of Nanostructured Electrocatalysts for Polymer Electrolyte Membrane Fuel Cells
Authors: Schneider Peter Maximilian , Sarpey Theophilus Kobina , Fichtner Johannes , Garlyyev Batyr , Bandarenka Aliaksandr S. 
Published: February 2024

Nanostructured catalysts are a promising class of materials to meet the requirements for the energy transition away from fossil fuels towards alternative, carbon-free, energy carriers, such as hydrogen. These catalyst materials boost the efficiency of energy conversion devices, such as fuel cells or electrolyzers, by accelerating their fundamental electrochemical reactions. Bottom-up synthetic routes for nanostructured materials often involve multiple synthesis steps and the use of surfactants, reducing agents or stabilizers. This results in complex and extensive synthesis protocols.[1] In recent years, a novel top-down synthesis approach to form metal nanoparticles has been established, in which bulk metal wires are immersed in an electrolyte and subsequently subjected to a high alternating potential. This leads to the generation of nanoparticles dispersed in the electrolyte.[2] There is no need for reducing agents, surfactants, or precursor solutions. The complete synthesis can be performed in one pot involving one main step with consequent washing and drying of the nanoparticles.
In this study, we synthesized Pt-based nanoparticles supported on Vulcan® carbon support (Pt/C) and tested their electrochemical activity towards the oxygen reduction reaction (ORR) for polymer electrolyte membrane fuel cells (PEMFCs). Firstly, we elucidated the influence of synthesis parameters such as potential amplitude, frequency, electrolyte composition, and concentration on the size and shape of Pt nanoparticles.[3] We continued with the synthesis of more complex nanostructures, such as Pt alloy nanoparticles. This introduces strain and ligand effects at the surface of the nanoparticles, which increases the electrocatalytic activity for the ORR. We demonstrated the facile, simple, and surfactant-free synthesis of highly active PtxPr/C[4] and PtxCu/C, as two examples for Pt alloy catalysts for the ORR, and give an outlook on other systems, such as PtxGd/C.

References:

[1] Chen et. al., Chem. Rev. 2010, 110, 3767-3804
[2] Yanson et. al., Angew. Chem. Int. Ed. 2011, 50, 6346-6350
[3] Garlyyev et. al., Nano Res. 2021, 14(8), 2762-2769
[4] Fichtner et. al., ACS Appl. Mater. Interfaces 2019, 11, 5, 5129–5135

Figure 1
Unlocking Bifunctional Electrocatalytic Performance of Co-MOF-Derived Catalysts for ORR and OER
Authors: Yusibova Gulnara , Kongi Nadezda , Karpichev Yevgen 
Published: February 2024

As the world is rapidly moving towards renewable energy technologies, the demand for efficient and cost-effective bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is increasing. Metal-organic framework (MOF)-based catalysts possess tunable and hierarchical porous structures with high surface area, making them superior to noble metal catalysts for energy storage technologies due to their high catalytic activity and stability.
In this study, we report a novel Co-N-C bifunctional oxygen electrocatalyst synthesized by carbonizing single metal Co-MOF precursor TAL-2. The optimized Co-N-C material demonstrated superior ORR/OER bifunctional catalytic activity compared to the commercial Pt/C and RuO2. The outcomes of this study highlight the considerable potential of utilizing a single metal Co-N-C catalyst as a facile precursor for the development of highly efficient electrocatalyst materials.
Rationalizing the Effect of the Redox-Inactive Metals on the Activity of Oxides in Oxygen Electrocatalysis
Authors: Kuznetsov Denis A. , Wu Yi-Hsuan , Müller Christoph R. 
Published: February 2024

The large-scale implementation of renewable energy conversion and storage technologies is a key challenge to transition to a sustainable society. One of the most critical elements towards this goal is the discovery of active, stable and inexpensive catalysts for electrochemical energy conversion processes, such as the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which are central for the efficiency of water-splitting electrolyzers, fuel cells and metal–air batteries.1 Manganese-based spinels, MxMn3-xO4, and ruthenium pyrochlores, M2Ru2O7
−
δ, are known as active catalysts for the ORR and OER, respectively, and were studied here as model systems to rationalize the effect of the incorporation (doping) of redox-inactive elements (M) into the structure on the catalytic performance of complex oxides in oxygen electrocatalysis.
We found a direct correlation between the ORR/OER activity of Mn3O4:M spinels (M = Mn, Cu, Zn, Mg, Ca, Sr),2 and Y1.8M0.2Ru2O7
−
δ pyrochlores (M = Y, Fe, Co, Ni, Cu),3 the lattice oxygen binding strength/lability and the formation enthalpy of the binary MO
x
oxides. We found experimentally that the activity of Mn3O4:M and Y1.8M0.2Ru2O7
−
δ in, respectively, ORR and OER, varies significantly depending on the nature of M. We observed that metals M with higher enthalpies of formation for the respective oxide weaken the oxygen binding on the surface of the complex oxide that correlates in turn with changes in ORR/OER activity. DFT studies captured changes in the electronic structure upon M substitution and allowed to correlate trends in the electronic band structure and the oxygen vacancies formation energies with the ORR/OER performance of the Mn3O4:M/Y1.8M0.2Ru2O7
−
δ catalysts. These activity trends are subsequently discussed in the framework of theoretically established correlations between the electrocatalytic activity and adsorption energies of catalytic intermediates. We demonstrated that the introduction of redox-inactive metal substituents/dopants into the host structure of a metal oxide is a highly versatile approach to tune the binding strength of reaction intermediates (determining the position of the catalyst on the ORR/OER activity volcano), and in turn improve the ORR/OER activity and also selectivity. This approach is a general concept that is transferrable to a broad selection of materials and processes associated with adsorption and redox reactions involving oxygen species.
References
(1) Seh, Z. W.; Kibsgaard, J.; Dickens, C. F.; Chorkendorff, I.; Nørskov, J. K.; Jaramillo, T. F. Science
2017,
355, eaad4998.
(2) Wu, Y.-H.; Mehta, H.; Willinger, E.; Yuwono, J. A.; Kumar, P. V.; Abdala, P. M.; Wach, A.; Kierzkowska, A.; Donat, F.; Kuznetsov, D. A.; Müller, C. R. Angew. Chem. Int. Ed.
2023,
62, e202217186.
(3) Kuznetsov, D. A.; Naeem, M. A.; Kumar, P. V.; Abdala, P. M.; Fedorov, A.; Müller, C. R. J. Am. Chem. Soc.
2020,
142, 7883-7888.
Trapped Platinum Single-Site Catalysts for the Hydrogen Evolution Reaction
Authors: Huang Po-Yuan , Tang Peng , Swallow Jack E. N. , Gianolio Diego , Weatherup Robert S , Pasta Mauro 
Published: February 2024

Trapped platinum single-site catalysts (Pt-SSCs) in defective carbon substrates are of particular interest for polymer-electrolyte membrane (PEM) water electrolysers due to their high Pt atom utilization for the hydrogen evolution reaction (HER). However, their intrinsic catalytic activity compared with metallic Pt nanoparticles remains a topic of debate in the field with opposing results reported. [1, 2] A detailed investigation of the bonding environment of Pt and its evolution at HER working conditions is therefore warranted in order to corelate the Pt single-site structure to its catalytic activity and stability.
Here, we present a detailed analysis on trapped Pt-SSC prepared by pyrolysing H2PtCl6 adsorbed on a polyaniline substrate. [3] We used in-situ heated scanning transmission electron microscopy, temperature-dependent X-ray photoelectron spectroscopy and operando X-ray absorption spectroscopy to follow the evolution of Pt’s bonding environment during pyrolysis and HER. We demonstrate that the trapped Pt-SSC is stable under HER potentials but with lower catalytic activity relative to commercial Pt nanoparticles. We also perform first principles calculations to elucidate the origin of the inferior activity.
Our results promote the understanding of the relationship between the structure of trapped Pt-SSC and its HER performance, and calls for a techno-economic analysis to assess the practicality of using Pt-SSCs in commercial PEM water electrolyzers.
References

Q. Yang, H. Liu, P. Yuan, Y. Jia, L. Zhuang, H. Zhang, X. Yan, G. Liu,Y. Zhao, J. Liu, S. Wei, L. Song, Q. Wu, B. Ge, L. Zhang, K. Wang, X. Wang, C.-R. Chang, and X. Yao, J. Am. Chem. Soc., 144, 2171 (2022).

J. Wang, H. Y. Tan, T. R. Kuo, S. C. Lin, C. S. Hsu, Y. Zhu, Y. C. Chu, T. L. Chen, J. F. Lee, and H. M. Chen, Small, 17, 2005713 (2021).

P. Tang, P.-Y. Huang, J. E. N. Swallow, C. Wang, D. Gianolio, H. Guo, J. H. Warner, R. S. Weatherup and M. Pasta, “Structure- property relationship of defect-trapped Pt single-site electrocatalysts for the hydrogen evolution reaction” Reasearch Square (2023), doi: 10.21203/rs.3.rs-2397818/v1.
Polymer Design Strategies for Alkaline Membrane Water Electrolysis
Authors: Park Eun Joo , Arges Christopher , Xu Hui , Bae Chulsung , Fujimoto Cy , Matanovic Ivana , Kim Yu Seung 
Published: February 2024

Water electrolysis is a carbon-free hydrogen production technology, making it a promising candidate to mitigate aggravating climate change. Ion exchange membranes are an essential component of membrane-based water electrolysis, enabling high hydrogen production efficiency through a zero-gap configuration. The recent research efforts to develop anion exchange membranes and electrode ionomers have made significant improvement in durability of alkaline membrane water electrolyzers without sacrificing performance and efficiency. Still, there are several factors related to polymer electrolytes that contribute to the voltage loss for water splitting in the alkaline condition including electrode local pH, the interface between membrane and electrodes, and electrochemical oxidation of ionomers at high potentials. This presentation will provide the state-of-the-art performance of alkaline membrane water electrolyzers with respect to the structure of anion exchange membranes and ionomers. The material design strategies and future directions to develop advanced polymer electrolytes will be discussed for this green hydrogen production technology.
Reference:

Park, E.J., Arges, C.G., Xu, H., Kim, Y.S. ACS Energy Lett.
2022
, 7, 10, 3447–3457

Motz, A.R., Li, D., Keane, A., Manriquez, L.D., Park, E.J., Maurya, S., Chung, H., Fujimoto, C., Jeon, J., Pagels, M.K., Bae, C., Ayers, K.E., Kim, Y.S. Mater. Chem. A
2021
, 9, 22670-22683

Matanovic, I., Kim, Y.S. Current Opinion in Electrochemistry
2023
, 38, 101218

Leonard, D.P., Lehmann, M., Klein, J.M., Matanovic, I., Fujimoto, C., Saito, T., Kim, Y.S. Advanced Energy Materials
2023
, 13, 2203488
Water Transport and Salt Precipitation in Anion-Exchange Membrane Electrolyzers
Authors: Koch Susanne , Disch Joey , Kilian Sophia K. , Metzler Lukas , Vierrath Severin 
Published: February 2024

The hydrophilic nature of hydrocarbon ionomers and membranes presents a major challenge in anion-exchange membrane (AEM) electrolysis, despite improved stability from reinforcements and modified polymer chemistry. Durability and performance are still highly influenced by the operation mode and water management within the membrane-electrode-assembly (MEA).
Dry cathode operation in AEM water electrolysis, where only the anode is supplied with liquid electrolyte (KOH), offers increased hydrogen purity but poses challenges for non-fluorinated anion-exchange polymers that are sensitive to water content. In-situ neutron imaging with high resolution (~6 µm effective resolution) revealed that adjusting the anion-exchange capacity of the cathode binder ionomer can retain membrane humidification (Fig. 1)1.
In the electrochemical reduction of CO2 using AEM, water management and salt precipitation are significant challenges. High-resolution neutron imaging of a zero-gap CO2 electrolyzer operating at 200 mA cm-² and 2.8 V showed salt precipitates penetrating the cathode gas diffusion layer, leading to blocked CO2 gas transport and a decay in Faraday efficiency. Salt accumulation was higher under the cathode channel of the flow field than the land2.
Both studies demonstrate the substantial impact of water management and salt precipitation on the operation of AEM-based electrolyzers and how neutron imaging can assist in addressing these challenges.

References

(1) Koch, S.; Disch, J.; Kilian, S. K.; Han, Y.; Metzler, L.; Tengattini, A.; Helfen, L.; Schulz, M.; Breitwieser, M.; Vierrath, S. Water management in anion-exchange membrane water electrolyzers under dry cathode operation. RSC Adv
2022, 12, 20778–20784.
(2) Disch, J.; Bohn, L.; Koch, S.; Schulz, M.; Han, Y.; Tengattini, A.; Helfen, L.; Breitwieser, M.; Vierrath, S.; High-resolution neutron imaging of salt precipitation and water transport in zero-gap CO2 electrolysis. Nat Commun
2022, 13, 6099.

Figure 1
Oxygen Evolution Reaction Activity of Iridium Oxide with Strange Structure, Its Toward PEM Water Electrolysis
Authors: Ishida Takanobu , Takeda Yuko , Watanabe Yuta , Aoki Naoya 
Published: February 2024

Water electrolysis is a promising approach of hydrogen mass production.PEM water electrolysis has advantages such as high current density operation and quick response against input electricity.From these advantages, PEM water electrolysis is adequate to the hydrogen mass production system adopted the renewable energy.Iridium oxide shows good oxygen evolution reaction(OER) activity and durability for PEM water electrolysis anode catalyst, but there are material supply and cost issues as it is precious metal.To solve these issues, a number of studies have been conducted to improve OER activity of Iridium oxide.
In this work, the crystal structure of iridium oxide is focused in order to improve OER activity.As a result of several synthesis survey, we have synthesized iridium oxide with unique structure and it shows more than four times OER activity compared to commercial catalysts in RDE.The mechanism for the high OER activity would be discussed based on the results of electrochemical properties, spectroscopy, and structural analysis.