Electric-field assistant prepared polyethersulfone (PES) membranes were selected as the research object in this paper, aiming to address how to control membrane morphology, mechanical property and water permeation at the same time through a simple and environmentally friendly method for filtration purposes. Three PES membranes were fabricated and denoted as MP1 (25% PES), MP2 (30% PES) and MP3 (35% PES). Results indicated that the electric field can be used as a feasible method to design desired membrane structure and performance, SEM observations shows average pore sizes of 0.062–0.095 μm, AFM images showed MP1 has rough surface with larger pores, and MP3 has smoother surface with finer pores. Tensile test results as well indicated that the mechanical properties of MP were evidently reinforced when adding PES, and all tensile strengths increased monotonous with increase in the concentration of PES, wherein MP3 had the best maximum tensile strength (5.64907407 MPa). FTIR spectra were in agreement with characteristic PES functional groups, XRD showed an overall amorphous nature and some semi-crystalline order developed that was predominantly exerted along the vertical direction to the support surface with concentration within PES-rich membranes. These findings account for the reported compromise of the filtration performance, MP1 presented in NWP with best permeability (4.2012164.L.m⁻2·h⁻1). bar⁻1; MP3 had better mechanical stability to the detriment of flux. All tests results demonstrated how membranes can be tailored to maximize either permeability (MP1) or mechanical strength and selectivity (MP3), thereby allowing them to be employed as direct water filtration materials and could be utilized as a support for advanced composite membrane systems.

With the increasing depth of coal mining, thick-hard overlying strata (THOS) often induce dynamic disasters such as rockbursts, posing significant threats to mine safety. This study focuses on the application of directional hydraulic fracturing roof pressure relief technology (HFRPRT) as a key disaster prevention technology in the Hongqinghe Coal Mine’s 3-1302 longwall face. An integrated monitoring system combining microseismic (MS) and acoustic emission (AE) data was established to quantitatively evaluate the fracturing process through multi-indicator analysis, including support pressure response, energy distribution, and surface subsidence. The results demonstrate that HFRPRT effectively weakened THOS integrity, reducing periodic weighting intervals by 25% and peak pressure intensity by 21.95%. Daily AE energy and event count increased by 154% and 636%, respectively, indicating enhanced microfracture propagation. MS events shifted to lower-energy patterns, with second-order events predominating (59.16%), highlighting the technology’s role in mitigating elastic energy accumulation and dynamic hazards. This research provides a theoretical foundation for optimizing hydraulic fracturing parameters in similar geotechnical conditions, advancing coal mine disaster prevention strategies.

Developing low-noble-metal, high-efficiency catalysts for volatile organic compound combustion is a pressing challenge. Herein, a Pt/InBO3 catalyst was fabricated via a photoreduction strategy for toluene combustion. Sol-gel-synthesized InBO3 (InBO3-SG) exhibits superior surface properties, including abundant oxygen vacancies, stronger Lewis acidity, and lower basicity. Photoreduction enables the in situ formation of ∼2 nm Pt nanoparticles with a high proportion of metallic Pt0 (∼88%) directly on the support surface, which induces an exceptional Pt utilization efficiency. Unlike conventional high-temperature reducing treatments, strong metal-support interaction (SMSI) can be realized under mild conditions, avoiding some unfavored side-effects. Mechanistically, Pt0 activates O2 to generate reactive oxygen species, while InBO3-SG promotes substrate adsorption, oxygen species migration, and product desorption. This system integrates a functional support and oxygen-activating metal species through SMSI, ensuring efficient toluene combustion. The optimized catalyst achieves a T90 of 227 °C and an average TOFPt of 6.54 × 10-2 s-1 with ultralow Pt loading (0.2 wt %). Notably, T90 can be further reduced to 151 °C by tuning the catalytic conditions. Systematic comparison reveals an inherent trade-off between T90 and TOFPt, highlighting the need for balanced design. Though based on a newly constructed system, the catalyst delivers performance comparable to or exceeding that of state-of-the-art Pt systems, especially regarding Pt utilization efficiency.

This study reports the development of Pt-based bimetallic catalysts on carbonaceous supports for direct non-oxidative n-butane dehydrogenation. Bimetallic particles are anchored at defects on the support surfaces. The support is crucial for establishing a proper bimetallic phase, while the promoter (Sn, In, Ga, Ge, Pb, or Zr) alters the Pt metallic phase through geometric and electronic effects, enhancing catalytic performance. The geometric effects of the bimetallic phase facilitate C-H cleavage and butane adsorption in an inclined position, as opposed to flat positioning; this specific organometallic intermediate helps prevent side reactions. Meanwhile, the electronic effects boost the electronic density at Pt sites, promoting olefin desorption and reducing coke formation. The combination of these effects proves particularly beneficial for In, Ge, and Ga in catalysts based on carbon nanotubes, as well as for In, Ge, and Sn in those supported on Vulcan carbon.

Codeveloped by the American Heart Association and the American Academy of Pediatrics, this publication presents the 2025 guidelines for basic life support during cardiopulmonary resuscitation and emergency cardiovascular care of the pediatric patient, excluding the newborn infant, and represents the first comprehensive update of treatment recommendations since 2020. Incorporating the results of structured evidence reviews from the International Liaison Committee on Resuscitation, these guidelines are for lay rescuers and health care professionals with recommendations designed to improve survival from sudden cardiac arrest and acute life-threatening cardiopulmonary problems. Existing guidelines remain relevant unless specifically updated in this publication. Topics reviewed include the initiation of cardiopulmonary resuscitation; pulse check; components of high-quality cardiopulmonary resuscitation; chest compression technique; support surfaces for cardiopulmonary resuscitation; opening the airway; coordination of shock and cardiopulmonary resuscitation; types of defibrillators or automated external defibrillators; defibrillator paddle or pad size, type, position; treatment of inadequate breathing with a pulse; and foreign-body airway obstruction. Key topics that are new, are substantially revised, or have significant new literature include the elimination of 2-finger chest compressions in infants due to ineffectiveness of achieving proper depth with a recommendation of 1-hand or 2 thumb-encircling hands technique; the immediate application and use of an automated external defibrillator with a pediatric attenuator if available for cardiac arrest; and in infants with severe foreign-body airway obstruction repeated cycles of 5 back blows alternating with 5 chest thrusts (no abdominal thrusts), and in children with severe foreign-body airway obstruction repeated cycles of 5 back blows alternating with 5 abdominal thrusts. Key Words: AHA Scientific Statements • cardiopulmonary resuscitation • chest compressions • defibrillator • foreign body airway obstruction • heart arrest • shockable rhythm • ventilation.

The gliding arc plasma technique (glidarc) was used for the precipitation and deposition of Mn or Fe oxides on zirconia fibers. Two types of fibers were used: commercial (Fib Zr(C)) and biomorphic (Fib Zr(B)) ZrO2 fibers, the latter produced using cotton as a biotemplate. Both series of supported catalysts were characterized physicochemically and morphologically. Scanning Electron Microscopy (SEM) analyses showed that Fib Zr(B) largely retained the morphology of cotton. Fib Zr(B) presented the tetragonal phase (t-ZrO2), while Fib Zr(C) exhibited the monoclinic phase (m-ZrO2). Using X-ray Diffraction (XRD), the cryptomelane phase (KxMn8O16) was identified only for Mn-Fib Zr(B). In the case of Fe-supported samples, the α-Fe2O3 phase appeared clearly in both biomorphic and commercial fibers. SEM and Transmission Electron Microscopy (TEM) images revealed that the precipitated iron oxides appeared to be better distributed than the manganese oxides, covering the outer surface of the fibrous supports more homogeneously. X-ray Photoelectron Spectroscopy (XPS) confirmed that Mn has an average oxidation state between 3+ and 4+, consistent with the cryptomelane phase detected by XRD. The synthesized supported systems were tested as catalysts in soot and CO oxidation, with the Mn-supported fibers proving to be more active than their Fe-containing counterparts in both reactions.

The most common method for the synthesis of copper‐containing supported catalysts is impregnation of the support with a copper salt solution. However, calcination and reduction of the resulting materials can lead to agglomeration of copper species and a decrease in catalytic activity. The synthesis of highly dispersed copper particles on the support surface can be performed using ammonia evaporation method with a copper ammine complex as a precursor. This review considers the effect of copper loading and the support nature on the structure of the obtained catalysts with a focus on the benefits of the ammonia evaporation method for preparation of the Cu/SiO 2 catalysts compared to other methods. This review summarizes the results concerning influence of the synthesis conditions of the ammonia evaporation method on the morphology and structure of Cu‐based catalysts. The effect of ammonia evaporation temperature and solution pH on copper dispersion, copper particle size, and reducibility of the Cu‐based catalysts is also included. The morphology of the silica support and the particle size of the silica sol have impact on the formation of copper phyllosilicate in the Cu/SiO 2 catalysts.

BACKGROUND: Different rigidities of a stator and a rotor of a rotodynamic machine causes an irregular load distribution between the segments of the thrust plain bearing. The increasing complexity of rotodynamic machine designs and their operating conditions contribute to this irregularity and reduce the bearing performance. One solution allowing to increase the performance of such bearings is mechanical alignment devices. Technical literature provides little information on the conditions of reciprocal travel of the elements of such devices and their influence on the bearing performance. In addition, there are barely any design recommendations. Thus, when developing new equipment, it is required to run heavy-duty tests of thrust bearings with alignment devices. AIM: To collect data on the reciprocal travel of elements, the impact of the contact surface shape on travels, and the types of resistance forces affecting the device performance and to develop recommendations on the use of contact surface shapes. METHODS: We selected a schematic model of the interaction of lower row levers of a mechanical alignment device with intermediate bodies, including spheres and supports installed in the housing. We have discussed nine models. The performance of all models was analyzed assuming that all parts are absolutely rigid. The calculations used various shapes and dimensions of the contact surfaces of lower row levers and housing supports. The ratios of the moment arms acting on the lever of the lower row of forces and travels in the contacts were adopted as efficiency criteria. RESULTS: When the lever of the lower row is turned, the arms of the moments of forces to the right and left of the support become unequal to each other. Sliding friction is present instead of rolling friction in the contacts of the levers with intermediate bodies. CONCLUSION: The support surface shape of the lower row lever has a significant effect on the alignment of forces across the segments. During design, it is required to select a support surface shape of the lower row lever and the housing support, which prevents the lever from rolling along the support.

Electron isolation effect of Ga induced asymmetric microenvironment of support surface of Cu/nGa-TA catalyst to establish electron-rich interface to boost CO2 hydrogenation to CH3OH

Boosting 2,5-furancarboxylic acid formation by improving support surface oxygen activity in AuPd/Ce1-xZrxO2 catalysts

Effects of Hold Support Surface Area Variation on Posterior Muscle Activity in Static Therapeutic Climbing Postures

The aim of this work was high-temperature synthesis of PtPdCoNiCu/C nanoparticles with high-entropy alloy (HEA) structure as catalysts for oxygen reduction reaction. The materials were synthesized using a highly dispersed PtPd/C support, which was impregnated with Cu, Ni, and Co precursors followed by their precipitation with an alkali. Subsequently, the material was subjected to thermal treatment in a tube furnace at 600 °C for 1 h in a stream of argon containing 5% hydrogen. In combination with HRTEM, element mapping and line scan, XRD, and XPS data, these results confirm the successful synthesis of five-component PtPdCoNiCu high-entropy alloy nanoparticles on the surface of the carbon support. The obtained materials are characterized by a high electrochemical surface area of up to 63 m2/g(PGM), as determined by hydrogen adsorption/desorption and CO-stripping, and a high specific oxygen reduction reaction (ORR) activity of approximately 269 A/g(PGM) at 0.9 V vs. RHE. The synthesized material demonstrated outstanding stability, as confirmed by an accelerated stress test of 10,000 cycles. After the test, the electrochemical surface area decreased by only 12%, while the catalytic activity for ORR even increased. The proposed synthetic strategy opens a new pathway for obtaining promising highly stable five-component HEA nanoparticles of various compositions for application in catalysts.

Immobilized proteins have been conceived as promising for developing assays, including biosensors and chromatographic methods. Conventional efforts are geared toward the attachment of purified or recombinant protein, while lacking strategies for capturing endogenous protein in live cells. Herein, we developed a rapid, two-step method for the target- and site-selective immobilization of endogenous natural γ-amino butyric acid receptors (GABAAR) directly from live hippocampal neuronal cells (HT22 cells). The method employed a ligand-tethered reagent as a recognition motif and a derivative of acyl-imidazole as an alkyne donor, which selectively introduces an alkyne click handle into specific sites of GABAAR. Subsequent click reaction between the alkyne-protein and azide-modified dye or support surface enables visualization of the receptor in live cells, as well as fabrication of GABAAR-immobilized surface plasmon resonance (SPR) sensor chips or affinity chromatography stationary phases. Compared to a typical affinity-driven one-step capture method, this approach significantly shortens the immobilization time from 6 h to 15 min while preserving receptor functionality. The immobilized endogenous GABAAR was successfully applied in two analytical platforms: as an SPR sensor chip for enhancing sensitivity in revealing drug-receptor interactions, and as a stationary phase in affinity chromatography, where it markedly improved resolution, selectivity, and accuracy in analyzing drug-receptor interactions. Such unique features indicate that the two-step strategy may be a versatile tool for modifying endogenous natural proteins in live cells while minimizing the influence on their functions. It has great potential to facilitate the construction of affinity analytical assays using immobilized endogenous proteins.

Achieving a significant reduction in the cost of proton exchange membrane fuel cells (PEMFCs) is an imminent goal, and decreasing the overall platinum loading in the membrane electrode assembly (MEA) is regarded as a critical means to achieve this objective. However, as the Pt loading decreases, the MEA performance drops sharply, which is mainly impeded by the mass transport resistance at the triple phase boundaries (TPBs) for O2 and H+ to reach the catalyst active site through the ionomer. In this research, we propose an effective strategy to achieve precise control of the three-phase microenvironment within catalyst layer by introducing thiophene sulfur (C-S-C) species onto the surface of the carbon support. FIB/slice-STEM EDX mapping (STEM-EDX mapping of focused ion beam-processed and microtome-sliced samples) and molecular dynamics (MD) simulation clearly demonstrate that the interaction between thiophene sulfur and the sulfonic group on the ionomer’s side chains enhances the uniformity of the ionomer distribution, thereby promoting the formation of ideal TPBs. Consequently, the local oxygen transport resistance in the catalytic layer is reduced from 0.236 s cm−1 to 0.047 s cm−1. This improvement achieves a high rated power density of 1.06 W cm−2@0.67 V and a Pt utilization efficiency of 8.47 W mgPGM−1, with Pt loading as low as 0.125 mgPt cm−2. These findings exceed the technology targets set by the United States Department of Energy (DOE).

The article provides a theoretical justification for the application of adaptive sport technologies in the phased restoration of functional capacities in football players following knee joint injuries. Knee injuries are shown to be among the most common and severe types of damage in modern football, often resulting in prolonged exclusion of athletes from training and competition, reduced levels of physical and sport-specific fitness, and, in some cases, the risk of premature termination of a sports career. The content of adaptive sport technologies suitable for rehabilitation programmes is revealed, including specialized exercise complexes in closed kinetic chains, proprioceptive and neuromuscular training, functional training, exercises aimed at stabilizing the knee joint and core muscles, as well as the use of unstable support surfaces, training devices, elastic resistance bands, aquatic exercises, massage, and kinesiotaping. Emphasis is placed on the importance of individualized rehabilitation programmes, comprehensive monitoring of functional parameters of the musculoskeletal and cardiorespiratory systems, as well as the psycho-emotional state of the athlete. The article concludes that further scientific development and practical testing of integrated rehabilitation programmes based on adaptive sport technologies are necessary to increase the effectiveness of recovery and prevent recurrent knee injuries in football players.

One of the alternatives to platinum catalysts for the cathode of polymer electrolyte fuel cells is transition metal oxide-based catalysts, such as TiO x , ZrO x , and NbO x . Although these catalysts have been considered for their potential because of their high chemical stability under acidic conditions, their low oxygen reduction reaction (ORR) activity requires significant improvement. A contributing factor to this low activity is the poor conductivity of oxides. To improve this, it is believed necessary to control the crystal phase, the size of the oxides, and the local conduction paths near the oxide particles. Generally, it is difficult to separate and discuss these factors independently, making it unclear which factor is the most influential. In this study, niobium oxide nanoparticles with significantly different sizes were synthesized using either the irradiation method or impregnation method for the preparation of catalysts precursors, followed by heat treatment. Here, we report on the comparison of ORR activity, focusing on the differences in the size of the niobium oxide nanoparticles in the catalyst.The irradiation method is a simple one-pot process, in which a glass vial containing ultra-pure water together with conductive carbon nanopowder and metal source (Nb2(C2O4)5) are irradiated with gamma-ray from a cobalt-60 source. The impregnation method places conductive carbon nanopowder and the metal source in ethanol, followed by a drying process to obtain the sample. Thus-prepared composite nanoparticles, acquired in powder form, were used as precursors. Polyacrylonitrile was added and the mixture was heat-treated in an ammonia atmosphere to prepare the catalyst. It is expected that polyacrylonitrile will be graphitized upon heat treatment, forming local conduction paths near the oxide particles.These samples were characterized by the techniques of TEM, XRD, and LSV. When the precursor prepared by the irradiation method was heat-treated, TEM observation revealed that the Nb-based nanoparticles on the surface of the carbon support had a particle size of 7 nm (Figure 1 (a)). Following heat treatment of the impregnation-prepared precursor, the size of the Nb-based nanoparticles on the surface of the support was 13 nm (Figure 1 (b)), indicating that each method of precursor preparation successfully produced Nb-based nanoparticles of different sizes. In both cases, XRD showed diffraction patterns corresponding to niobium oxynitride. Additionally, composition ratios of niobium oxynitride determined from Vegard’s law, assuming NbO x N1-x , were consistent regardless of the precursor preparation method.These catalytic activities were evaluated using Linear Sweep Voltammetry in an acidic medium, based on the open circuit potential in oxygen and current density. After heat-treating the irradiation-prepared precursor, the open circuit potential and current density were slightly higher compared to the impregnation method; however, no significant difference was observed. Using a model based on several assumptions, it was suggested that the dominant factor affecting ORR activity is not the size of the metal oxide nanoparticles, but the length of the local conduction paths near the oxide nanoparticles. The present study revealed that the ORR activity in niobium oxide nanoparticle catalysts does not significantly depend on the size of the oxide nanoparticles.[Acknowledgments]The authors thank Koga Isotope Co. Ltd. for their cooperation with the gamma-ray irradiation. XAS experiments were performed at the NW-10A beamline of KEK under the approval of the Photon Factory Program Advisory Committee (Proposal No. 2022G074). This study was supported by JSPS KAKENHI (Grant Nos. 23K04912 and 24KJ1592).Figure 1: TEM images of the samples obtained from heat treatment of the precursor prepared by the (a) irradiation method and (b) impregnation method. Figure 1

Interconnected mesoporous carbons (IMCs) are an essential catalyst support technology for proton exchange membrane fuel cell (PEMFC) and water electrolyzer (PEMWE) applications, offering an optimized pore architecture for good catalyst dispersion and balanced mass transport, which uniquely enables efficient utilization of precious metal catalysts. While IMCs generally display superior PEMFC performance when compared to microporous or nonporous catalyst supports, the performance gains are not without tradeoffs as the mesoporous structures tend to produce catalysts with comparatively high proton transport resistance. The proton transport resistance is typically ascribed to two factors: lengthened ion transport paths between the ionomer and catalyst nanoparticles that are deposited in the interior of the mesoporous carbon support and the lowered wettability of mesopores vs. micropores that is exacerbated under dry conditions. To further improve the performance of IMC-based PEMFC catalysts, especially under dry conditions, the proton transport resistance of IMCs must be specifically targeted and optimized by research and development efforts. Here, we discuss strategies for reducing proton transport resistance in IMCs through precise control of support structure, composition, and surface chemistry. The platform for this study is Pajarito Powder’s Engineered Catalyst Supports (ECS), materials made using the proprietary VariPore TM process that allows for facile tuning of pore size, pore volume, and support surface area. Combined with advanced pre- and post-processing strategies, we present a series of novel ECS-based platinum (Pt) catalyst materials that explore the structure/performance relationships in IMCs affecting both proton transport resistance and overall PEMFC performance. Catalyst structures are characterized in detail by a combination of gas sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectroscopic methods, while catalyst performance is probed in full membrane electrode assembly (MEA) tests for both beginning of life (BOL) and end of life (EOL) catalyst performance. Proton transport resistance is measured both by electrochemical impedance spectra (EIS) methods and by CO-stripping measurements of Pt utilization as a function of inlet relative humidity (RH). Taken together, this study provides a holistic discussion on the rational design of IMCs through structure/function understanding to reduce proton transport and improve electrocatalyst performance.

Polymer electrolyte membrane fuel cells (PEMFC) offer a promising alternative, climate-friendly powertrain solution, in particular for heavy-duty applications such as commercial vehicles, trains, airplanes or ships. However, widespread market penetration is still curbed, amongst others due to high material cost and limited durability [1]. In order to meet the harsh lifetime requirements demanded for heavy-duty usage, a better understanding of PEMFC aging and the impact of operating conditions is necessary.In this work, PEMFC degradation is studied with a transient multicomponent and multiphase simulation model on the cell-level. In the model, aging is assumed to occur primarily due to a loss of the electrochemically active surface area (ECSA) in the cathode catalyst layer via platinum dissolution and Ostwald ripening [2]. In addition, and as opposed to pre-existing works, the model furthermore distinguishes between external platinum on the surface of the carbon support and internal platinum within the mesopores of the catalyst. In order to investigate the impact of different operating conditions on the PEMFC performance loss due to catalyst degradation, a load cycle for heavy-duty applications is then simulated. The load cycle was recently developed within the project PEMTASTIC [3] and consists of dynamic load changes as well as several short stops and a long stop period.The simulation results elucidate how catalyst degradation is affected by operating parameters and thus support a better understanding of long-term PEMFC performance loss under representative heavy-duty conditions. Hereby, the study promotes the further development of optimized operating strategies aiming to minimize aging effects for the prolongation of PEMFC lifetime. Acknowledgements The research leading to these results was supported by the project PEMTASTIC (Grant Agreement No.101101433), funded by the Clean Hydrogen Partnership and its members Hydrogen Europe and Hydrogen Europe Research.

Introduction After 2035, extremely high cell performance is required for PEFCs used in fuel cell electric vehicles in Japan [1]. To improve cell performance, a new carbon support is needed that not only enhances oxygen reduction reaction activity of the Pt catalyst but also suppresses ionomer poisoning and improves oxygen diffusivity [2]. From this viewpoint, mesoporous carbon (MPC) has recently attracted attention as a carbon support material for Pt and Pt-based catalysts [2-4]. Especially when PEFCs are operated under high temperature and low relative humidity (RH) conditions [1], improvement in the cell performance is a major challenge. In this study, surface of MPC support was modified with -SO3H functional group and effect of the modification on cell performance under low RH conditions was investigated. Experimental MPC of CNovel® MH-18 (primary particle size: 800 nm, SBET: 1,346 m2/g, central mesopore diameter 4 nm, TOYO TANSO Co. Ltd.) was used as carbon support for the Pt catalysts. p-aminobenzenesulfonic acid (sulfanilic acid) was used as a diazonium reagent to modify MPC support with sulfonate functional group (-SO3H) [5-7]. Sulfanilic acid was dissolved in 35 mL of 0.4 M H2SO4 aq., followed by the dropwise addition of NaNO2 aq. (1.5 mmol) under N2 gas atmosphere at 5°C with stirring. 700 mg MPC support was added to the solution and temperature was raised to 60°C and stirred in air for 4 h (MPC-SO3H (1/1)). The -SO3H modified MPC was filtrated and washed by ultrapure water for 5 times and finally boiled in ultrapure water for 2 h. MPC support modified with -SO3H functional group reduced by one-half as described above was also prepared (MPC-SO3H (1/2)). Pt/MPC and Pt/MPC-SO3H catalysts were synthesized by an alcohol reduction method [8]. 500 mg of MPC or MPC-SO3H support and a Pt precursor of Pt(NO2)2(NH3)2-HNO3 aq. (500 mg as metallic Pt) were added to EtOH/H2O mixed solvent (37.5 mL/250 mL) and refluxed at 90°C for 4 h under N2 gas atmosphere. The MPC and MPC-SO3H supports were characterized by N2 gas adsorption and TEM-EDX composition analysis. The performance of H2-air supplied fuel cell was evaluated using a single cell (active area: 1 cm2) with straight flow channels. NafionTM DE2020 (EW: 1,100) was used as ionomer for the catalyst ink preparation (I/C ratio: 1.2), and NafionTM NR 211 (thickness: 25 μm) was used as membrane. The Pt loading of the cathode catalyst layer was 0.1 mg/cm2. The cell temperature was set at 80°C and humidified to 95 to 35% RH with a back pressure of 150 kPa (abs.). Results and Discussion Figure 1 shows t-plots for N2 gas adsorption on MPC and MPC-SO3H supports. In MPC-SO3H supports, external surface area of unmodified MPC (83 m2/g) did not significantly change, but internal surface area of unmodified MPC (1263 m2/g) and pore volume of unmodified MPC (1.53 cm3/g) decreased slightly. Figure 2 depicts cross-sectional TEM image and TEM-EDX compositional maps of carbon and sulfur in MPC-SO3H (1/1) support, indicating that sulfur (-SO3H) is uniformly distributed throughout MPC support.Figure 3 demonstrates I-V performance of MEAs with MPC and MPC-SO3H (1/1) supported Pt cathode catalysts. At 75% RH, there is little difference in I-V performance between Pt/MPC and Pt/MPC-SO3H catalysts. At low humidities of 55% and 35% RH, cell voltages of Pt/MPC-SO3H catalyst were higher than that of Pt/MPC catalyst. However, at 95% RH, Pt/MPC-SO3H catalyst exhibited lower cell voltages, which may be due to increased wettability and flooding caused by -SO3H functional group modification. The differences in cathode impedance between Pt/MPC and Pt/MPC-SO3H (1/1) catalysts at various RHs are shown in Fig. 5. The difference is larger at lower RH, suggesting that MPC-SO3H support contributes to the improved proton conductivity under low RH conditions. Acknowledgements This study was partly supported by NEDO, Japan.

Introduction One of the key components of polymer electrolyte fuel cells (PEFCs) is the polymer electrolyte membrane (PEM). The PEM facilitates proton transport, acts as an electronic insulator to prevent short circuits, and prevents the direct reaction between hydrogen gas and oxygen in the air. A major technical issue with PEMs is the decomposition of their molecular structure due to chemical degradation. This leads to decreased proton conductivity, increased hydrogen and oxygen crossover, and reduced mechanical strength, all of which significantly impact the performance and durability of the PEMs (1). Previous studies have suggested that Fe impurities in the carbon support mainly exist on the surface, and the amount of these impurities may affect membrane degradation (2). Therefore, this study aims to investigate whether the removal of Fe from the surface of the carbon support can suppress PEM degradation. Experimental In the experiments, Ketjen Black (denoted as KB, EC600JD, Lion Specialty Chemicals Co., Ltd., Japan) was used as the carbon support. Acid treatment was performed to remove Fe impurities from the surface of the KB (Figure 1). KB was added to 2 mmol/L or 200 mmol/L HNO₃ and stirred for 2 h. Then, ultrapure water was added to the catalyst dispersion, followed by vacuum filtration to separate the solid carbon support and the liquid solvent. The carbon support powder was dried overnight in a thermostatic oven set at 100°C. These samples were labeled as KB-AT-2 and KB-AT-200, respectively. To measure the Fe content in each carbon support, the powder was dispersed in 1 mol/L HNO₃ to dissolve the surface impurities, and quantitative analysis was conducted using the resulting solvent.Catalysts were prepared by loading Pt on KB, KB-AT-2, and KB-AT-200. For the anode catalyst, Pt/KB (TEC10E50E, Tanaka Kikinzoku Kogyo, Japan) was used. For the cathode catalyst, the following were used: (i) Pt/KB, (ii) Pt/KB-AT-2, and (iii) Pt/KB-AT-200. Using the prepared MEAs, a 100-hour open circuit voltage (OCV) holding durability test was conducted. After the test, the thickness of the PEMs was measured by cross-sectional observations of the MEAs using focused-ion-beam scanning electron microscope (FIB-SEM). Results and discussion Figure 2 shows cross-sectional images of MEAs using Pt/KB and Pt/KB-AT-200 as the cathode catalyst after 100-h OCV holding test. These results clearly indicate that acid treatment of the carbon support surface to remove Fe impurities can suppress the chemical degradation of PEM. In this presentation, the effectiveness of removing Fe impurities from the surface of carbon supports as a method for suppressing chemical degradation of the PEM will be presented. Acknowledgements This paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). An educational part for young scientists was supported by the Japan Science and Technology Agency (JST) through the program “Adopting Sustainable Partnerships for Innovative Research Ecosystem” (ASPIRE), Grant Number JPMJAP2307. The presenting author (S. Nakamura) is supported by JST SPRING, Grant Number JPMJSP2136, and the Miyamoto Jun-ichi Hydrogen Research Award of Kyushu University. References M. Zatoń, J. Rozière, and D. J. Jones, Sustain. Energy Fuels, 1, 409 (2017).S. Nakamura, K. Sanami, Z. Gautama, Z. Noda, M. Yasutake, S. M. Lyth, M. Nishihara, and K. Sasaki, ECS Trans., 114 (5), 183 (2024). Figure 1