Catalyst layers in proton exchange membrane fuel cells consist of platinum-group-metal nanocatalysts supported on carbon aggregates, forming a porous structure through which an ionomer network percolates. The local structural character these heterogeneous assemblies is directly linked to the mass-transport resistances and subsequent cell performance losses; its three-dimensional visualization therefore interest. Herein we implement deep-learning-aided cryogenic transmission electron...

The application of Pt-alloy cathode catalysts for proton exchange membrane fuel cells (PEMFCs) is hampered by the leaching alloyed transition metal into ionomer phase electrode assembly (MEA). To date, accelerated stress tests used to assess degradation lack non-destructive, facile diagnostics quantify in an operating PEMFC. Here, we present a method based on electrochemical impedance spectroscopy that exploits high sensitivity frequency resistance (HFR) at low relative humidity (RH) cation...

Tailored design of carbon supports and their pore morphologies is crucial to achieve the ambitious durability performance targets for future proton exchange membrane fuel cells (PEMFCs). We compared platinum catalysts supported on solid Vulcan carbon, porous Ketjenblack accessible modified in a voltage cycling-based accelerated stress test (AST) with frequent intermittent characterizations. derived how catalyst affect cell electrochemical properties (electrode roughness factor, ORR activity,...

The morphology of carbon supports for Pt-based proton-exchange membrane fuel cell (PEMFC) catalysts strongly determines their performance at both low and high current density. Porous with internally deposited Pt nanoparticles sustain kinetic activity by shielding from ionomer adsorption, albeit the expense poor oxygen mass transport. This work systematically explores an oxidative pre-treatment commercial Pt/Ketjenblack, termed localized oxidation , which drastically improves transport...

Platinum-yttrium alloys (Pt x Y) are suggested to have superior oxygen reduction reaction (ORR) activity and long-term stability in proton exchange membrane fuel cells (PEMFCs). However, the actual ORR of a Pt Y catalyst with high electrochemically active surface area ( ECSA ) PEMFC remains uncertain. Here, Ketjen black (KB) carbon supported Y/KB (∼60 m 2 /g) was synthesized using nitride precursor. Based on elemental analysis, XRD, electron microscopy, mass-balance based model, it shown...

Polymer electrolyte fuel cells are an essential technology for future local emission-free mobility. One of the critical challenges thriving commercialization is water management in cells. We propose small- and wide-angle X-ray scattering as a suitable diagnostic tool to quantify liquid saturation catalyst layer determine hydration ion-conducting membrane real operating conditions. The that may occur operando data collection described detail─separation anode cathode, cell alignment beam,...

Journal Article Cryo-Electron Tomography for Imaging and Quantitative Analysis of Beam-Sensitive Fuel Cell Materials Get access Robin Girod, Girod Institute Materials, École Polytechnique Fédérale de Lausanne, Switzerland Search other works by this author on: Oxford Academic Google Scholar Timon Lazaridis, Lazaridis Chair Technical Electrochemistry, Department Chemistry Catalysis Research Center, Technische Universität München, Germany Hubert Gasteiger, Gasteiger Vasiliki Tileli...

Zero-emission electricity production for stationary or mobile applications can be realized by PEM fuel cells (PEMFCs), making it an important constituent a renewable energy transition. Especially relevant in heavy-duty applications, high power output at low current densities (related to mass activity, MA) under dry conditions is necessary meet the efficiency targets. [1] In general, activity of Pt/C catalyst negatively affected ionomer poisoning, which describes adsorption endgroups onto...

Platinum catalysts supported on porous carbons are considered state-of-the-art for proton-exchange membrane fuel cells (PEMFCs) due to their ability protect Pt nanoparticles within the internal pores of primary carbon particles. This shielding enables high oxygen reduction reaction (ORR) activity by separating particles from ionomer contact and endows them with greater resilience against voltage cycling-induced degradation. However, pore enclosure impedes diffusion platinum at current...

Proton exchange membrane fuel cell (PEMFC) applications in the heavy-duty mobility sector have attracted increasing attention due to their flexible scalability terms of energy and power density. The challenging high efficiency targets can be met by introducing platinum-cobalt alloy (Pt x Co/C) catalysts which exhibit a 1.5-3x higher kinetic activity for oxygen reduction reaction (ORR) as compared carbon supported platinum (Pt/C) catalysts. 1 Despite better beginning-of-life performance Pt...

Nowadays, proton exchange membrane fuel cells (PEMFCs) are envisioned for heavy-duty vehicles (HDVs) such as trucks and buses, due to their high power density, low emissions, quiet operation. 1 However, be viable HDVs, PEMFCs require cathode catalyst materials that highly stable durable in order maintain performance over at least 30,000 hours of One well-known challenge is voltage cycling the leads significant losses electrochemically active surface area ( ECSA ) Pt-dissolution subsequent...

One of the major degradation mechanisms limiting long-term durability proton exchange membrane fuel cells (PEMFCs) is loss platinum electrochemically active surface area (ECSA) carbon-supported (Pt/C) cathode catalyst, caused by Pt dissolution that followed both Ostwald ripening nanoparticles and into ionomer phase [1]. The ECSA accelerated when subjecting PEMFCs to extended load-cycling inducing concomitant cycling potential. To this end, stress tests (ASTs) can be conducted either...

In the course of this work, two iron oxide nanopowder samples (a mixture FeO / γ-Fe 2 Ο 3 -Fe O 4 ) were composed, implementing methodology. The synthesis used is a simple thermal decomposition route organometallic precursors. precursor was acetylacetonate (Fe (acac) which underwent reductive degradation. shape nanoparticles examined and determined by reaction time ratio surfactants, oleic acid (OA) oleylamine (OA m ). first sample controlled oxidation in air to transform non-magnetic phase...

In order to reach the target of climate neutrality by end 2050, an increasing interest in application proton exchange membrane fuel cells (PEMFCs) for heavy duty vehicles (HDVs), such as trucks and buses has developed recently. However, HDVs require highly stable durable cathode catalyst materials, which retain sufficient performance at least 30,000 h load-cycling during normal operation. 1 It is well known that concomitant voltage cycling leads severe losses electrochemically active surface...

Mass market adoption of PEM fuel cells (PEMFCs) for emission-free propulsion still hinges on catalyst materials that remain highly active at low platinum loadings without comprising durability the PEMFC system. A promising path towards this goal is development novel carbon support morphologies, as research efforts throughout past decade have shone light their importance determining overall cell performance and mitigating degradation. [ 1-2] Briefly, porous supports such Ketjenblack...

Operando scanning small- and wide-angle X -ray scattering (SAXS&WAXS) at the cSAXS beamline of Swiss Light Source was employed in this study to examine water saturation polymer electrolyte fuel cell (PEFC) component, particularly nanoscale pore space catalyst layers (CL) membrane hydration state. A small beam size (≈7x30 microns) ≈0.6 microns through-plane step enabled resolve bulk CLs (Pt/C Ketjen Black based, 0.1 mg Pt /cm 2 ; ≈7 thick) separated by a 15-micron membrane. Additionally,...

The application of proton exchange membrane fuel cells (PEMFCs) in light-duty vehicles (LDV) has dominated the cell research field for past decades. To reduce LDV FC system cost to 30 $/kW by 2025 driven search highly active cathode catalysts that could substitute costly state-of-the-art Pt-alloy or loadings < 0.125 mg Pt /cm 2 . 1, As novel ORR catalyst continue emerge, theoretical calculations have turned attention on Pt-rare earth (RE) alloys, such as platinum-yttrium alloys were...