Electrocatalysts For Fuel Cells Research Articles

Trimetallic Alloys as an Electrocatalyst for Fuel Cells: The Case of Methyl Formate on Pt3Pd3Sn2.

The shift toward renewable energy sources plays a central role in the quest for a circular economy. In this context, methyl formate (MF) has garnered attention as a compelling hydrogen carrier and alternative fuel, because of its remarkable characteristics (energy density, ease of storage and transport, and low boiling point). In this study, DFT calculations supported by online electrochemical mass spectroscopy (OE-MS) were performed to investigate the MF electro-oxidation (MFEO) on Pt3Pd3Sn2 (111). The DFT calculations provide insight into the role of Pt, Pd, and Sn atoms in MFEO. Pt and Pd together provide a preferred active site for initiating MFEO through the O-H bond scission, and Sn plays an essential role in the mitigation of CO through oxygenation or water activation. By comparing the reaction energies and activation barriers for all possible reactions in MFEO, the suggested path necessitates a minimum energy of 0.14 eV to initiate the MFEO. This value was supported by the experimental results, showing that the oxidation wave of MF starts at 0.15 V (70 °C). Density functional theory (DFT) results, supported by OE-MS, indicate that the hydrolysis of MF prior to MFEO is not preferred on Pt3Pd3Sn2 (111) surfaces, although the formation of methanol is plausible via a CH3O intermediate. Among the three small organic molecules (SOMs) studied─MF, methanol, and formic acid─MF has the lowest activation energy for the initial bond breaking that starts the whole oxidation process (0.13 eV), compared to formic acid (0.45 eV) and methanol (0.61 eV); thus, MF is the preferred fuel on Pt3Pd3Sn2 (111).

Effective Fuel Cell Electrocatalyst with Ultralow Pd Loading on Ni-N-Doped Graphene from Upcycled Water Bottle Waste

Effective Fuel Cell Electrocatalyst with Ultralow Pd Loading on Ni-N-Doped Graphene from Upcycled Water Bottle Waste

(Invited) Electrocatalysts for the Oxygen Reduction Reaction and the Hydrogen Evolution Reaction Based on “Core-Shell”, “PGM-Free” Carbon Nitride Systems

The key electrochemical processes at the heart of the “hydrogen economy” involve: (i) the recombination of hydrogen and oxygen to form water in fuel cells (FCs); and (ii) the splitting of water to yield hydrogen and oxygen in water electrolyzers (ELs). Depending on the particular device taken under consideration, such processes typically occur either in a highly acidic environment (e.g., in proton-exchange membrane fuel cells, PEMFCs, and in proton-exchange membrane electrolyzers, PEMELs) or in strongly alkaline conditions (e.g., in anion-exchange membrane fuel cells, AEMFCs; and in anion-exchange membrane electrolyzers, AEMELs). In both cases, such processes require suitable electrocatalysts (ECs) to minimize overpotentials and achieve a performance and durability level compatible with applications. State-of-the-art ECs for both FCs and ELs typically suffer from important drawbacks such as: (i) high overpotentials; (ii) a poor durability; and (iii) a high loading of strategic elements, with a particular reference to platinum-group metals (PGMs); correspondingly, significant concerns are raised due to potential supply bottlenecks.In this work, a new family of “PGM-free” ECs is proposed, especially targeted to promote the oxygen reduction reaction (ORR) and the hydrogen evolution reaction (HER) in either/both the acidic and the alkaline environment. The ECs are obtained by means of a multi-step synthetic process [1]. In the first step a precursor is prepared by coupling a carbon black support with a hybrid inorganic-organic macromolecular system consisting of an organic binder coordinating: (i) a first-row transition metal (e.g., Fe) meant to act as the “catalyst”; and (ii) Sn, playing the role of “co-catalyst”. Subsequently the precursor undergoes a multi-step pyrolysis process followed by suitable chemical treatments meant to remove labile species and reaction byproducts, yielding the final EC. Optionally, the EC may be coupled with an additional aliquot of the hybrid-inorganic precursor. In this case, further pyrolysis/chemical treatment steps are carried out to obtain the final product.The final “PGM-free” ECs proposed herein exhibit a “core-shell” morphology. The carbon black “core” is covered by a carbon nitride “shell” stabilizing the active sites based on the “catalyst” and the “co-catalyst” into C- and N- “coordination nests”. The ECs undergo an extensive physicochemical characterization, meant to determine: (i) the chemical composition, both in the bulk and on the surface (adopting analytical techniques such as ICP-AES, CHNS microanalysis, EDX and NAP-XPS); (ii) the morphology (by means of UHR-SEM); (iii) the porosimetric features (by nitrogen and water physisorption studies); and (iv) the structure (e.g., through wide-angle X-ray diffraction). The kinetics and reaction mechanism of the proposed ECs in the ORR and HER are determined by advanced electroanalytical techniques, with a particular reference to cyclic voltammetry with the thin-film rotating ring-disk electrode (CV-TF-RRDE). The synthetic parameters are finally correlated with the results of the physicochemical and the electrochemical characterization, shedding light on the most promising avenues to guide the preparation of further ECs exhibiting improved performance and durability, suitable for implementation in next-generation FCs and ELs.

Investigating the pH-Dependent Activity, Selectivity, and Dynamics of Metal Nitride Electrocatalysts for Fuel Cells and Electrolyzers

To mitigate climate change caused by the use of fossil fuel energy sources, there is an urgent need to decarbonize our energy systems. Developing fuel cell and water electrolysis technologies to support a green hydrogen infrastructure is a promising strategy for this transition. In both hydrogen fuel cells and water electrolyzers, platinum-group metal (PGM) materials such as Pt and IrOx are benchmark electrocatalysts, exhibiting high activity and stability for kinetically-hindered reactions including the oxygen reduction reaction (ORR), the oxygen evolution reaction (OER), and alcohol oxidation reactions (AOR; alternative anodic reactions to OER). Despite their remarkable performance, the high cost and low abundance of PGMs is a key factor limiting the widespread adoption of these technologies.Cobalt- and nickel-based metal and oxide catalysts have emerged in the literature as a promising PGM-alternative class of low-cost, high-performing ORR, OER and AOR catalysts. Substituting oxides with nitrides or other chalcogenides could be a favorable method to improve activity, selectivity, and stability; however, the material stability of these non-oxides as a function of reaction, potential window, and pH is not well-understood. Furthermore, the most active of these materials tend to be carbon-supported nanoparticles with complicated and heterogeneous active sites, which makes deconvoluting the role of the cobalt and secondary element(s) (e.g. N, C, etc.) difficult.With the goal of developing fundamental activity-stability relationships for non-precious metal-based electrocatalysts, we have developed a synthesis procedure for well-defined Co- and Ni-based thin film materials. Focusing on Co, using physical vapor deposition followed by thermal treatments with ammonia and an Sb-based precursor, we have synthesized CoxSbyNz thin films of varying compositions. These synthesis methods can be extended to synthesize a broad class of metallic (Co, Ni, Fe, etc.) or bimetallic X-ide (X = N, S, etc.) thin film materials. We evaluate ORR, OER, and AOR activity with cyclic voltammetry, demonstrating that activity depends on composition and electrolyte pH. Specifically, for Co-based thin films for ORR, we see improvement in activity with the incorporation of N, and improvement in acid-stability with the incorporation of Sb. In addition to ex situ post-characterization with x-ray photoelectron spectroscopy, we utilize in situ techniques to evaluate catalyst stability in real time. We monitor time- and potential-dependent cobalt dissolution with an on-line inductively coupled plasma mass spectrometer (ICP-MS) as well as nitride degradation with electrochemical mass spectrometry (EC-MS). In acidic media, the stability of CoxN is limited by Co dissolution, while in alkaline media stability appears to be limited by nitride degradation. With highly active non-oxide materials it is typically too complicated to disentangle the role of each individual element within an electrocatalyst. With our stepwise material synthesis platform and multifaceted characterization techniques we are able to individually probe the material stability and product-specific activity of each element. These results provide new insights to guide the strategic design of electrocatalysts across a range of reactions and applications.

One-pot synthesis of platinum-samarium dendritic nanocrystals with tunable elemental compositions for efficient electrocatalytic methanol oxidation via f-d hybridization interaction

Metallic doping is widely recognized as an effective approach to modulate the intrinsic electronic structure of platinum (Pt)-based electrocatalysts, thereby enhancing their performance in fuel cells. Recent progress mainly focused on doping metals from d-block or p-block of the periodic table to promote d-d or p-d hybridization interactions, while f-block metals, such as rare earth metals, have received less attention. In this study, samarium (Sm)-doped Pt nanocrystals with a dendritic nanoparticle morphology were synthesized with precise control over their elemental composition. The key to achieving this unique morphology was the co-reduction of halide-free Pt and Sm precursors by glucose in the presence of cetyltrimethylammonium chloride (CTAC) in N-oleyl-1,3-propyldiamine (OPDA) at an elevated temperature. When employed as an electrocatalyst for the methanol oxidation reaction (MOR) in an alkaline medium, the optimized Pt86.4Sm13.6 nanodendrites/C exhibited nearly a 7-fold increase in specific activity, accelerated reaction kinetics, and enhanced long-term durability compared to commercial Pt/C. This improved electrocatalytic activity is attributed to the unconventional f–d hybridization interactions, which weaken CO binding and reduce the CO poisoning effect. The f-d hybridization interactions were further elucidated by density functional theory (DFT) calculations, which showed that the stronger interaction between OH and Sm-doped Pt(111) surface exhibits a benefit to combine with CO to form COOH and then release CO2, affirming the critical role of Sm-doping in improving the MOR activity. This research offers a viable strategy for creating rare earth metal-doped bimetallic nanocrystals with controlled morphology and may be extended to the rational design of high-performance fuel cell electrocatalysts based on f-d orbital hybridization.

Composites of Titanium-Molybdenum Mixed Oxides and Non-Traditional Carbon Materials: Innovative Supports for Platinum Electrocatalysts for Polymer Electrolyte Membrane Fuel Cells.

TiO2-based mixed oxide-carbon composite support for Pt electrocatalysts provides higher stability and CO tolerance under the working conditions of polymer electrolyte membrane fuel cells compared to traditional carbon supports. Non-traditional carbon materials like graphene nanoplatelets and graphite oxide used as the carbonaceous component of the composite can contribute to its affordability and/or functionality. Ti(1-x)MoxO2-C composites involving these carbon materials were prepared through a sol-gel route; the effect of the extension of the procedure through a solvothermal treatment step was assessed. Both supports and supported Pt catalysts were characterized by physicochemical methods. Electrochemical behavior of the catalysts in terms of stability, activity, and CO tolerance was studied. Solvothermal treatment decreased the fracture of graphite oxide plates and enhanced the formation of a reduced graphene oxide-like structure, resulting in an electrically more conductive and more stable catalyst. In parallel, solvothermal treatment enhanced the growth of mixed oxide crystallites, decreasing the chance of formation of Pt-oxide-carbon triple junctions, resulting in somewhat less CO tolerance. The electrocatalyst containing graphene nanoplatelets, along with good stability, has the highest activity in oxygen reduction reaction compared to the other composite-supported catalysts.

In Situ Formation of Highly Durable Subnanometer Platinum Particle Electrocatalysts for Polymer Electrolyte Fuel Cells.

The durability of Pt nanoparticle catalysts is currently the most important factor limiting the widespread use of polymer electrolyte fuel cells (PEFCs). Specifically, the Pt nanoparticles in standard carbon black-supported Pt nanoparticle (Pt/CB) catalysts repeatedly aggregate on the CB surfaces during PEFC operation, thus, reducing the performance of the cell. Therefore, PEFCs must contain large quantities of Pt to maintain sufficient service lifetimes. This is the main factor hindering the reduction of the cost of PEFCs. The present research demonstrates that ultrafine Pt particles (Ptsubnanoes) having diameters of approximately 0.5 nm can be formed in situ from a platinum chloride complex (PtCl n ) on a carbon-based material doped with Fe and N via the dissolution and reprecipitation of Pt in the PtCl n during potential cycling in a 0.1 M HClO4 solution. The Ptsubnanoes are immobilized by both Fe and N in the support material. The mass-based catalytic activity of this material during the oxygen reduction reaction is eight times higher than that of a standard Pt/CB catalyst and is maintained even after 100,000 potential step cycles (0.6 ↔ 1.0 V). The present results provide guidelines for the development of highly durable yet active membrane electrode assemblies that minimize the use of Pt.

VOx Matrix Confinement Approach to Generate Sub-3nm L10-Pt-Based Intermetallic Catalysts for Fuel Cell Cathode.

Pt-based intermetallic compounds (IMCs) are considered as a class of promising fuel cell electrocatalysts, owing to their outstanding intrinsic activity and durability. However, the synthesis of uniformly dispersed IMCs with small sizes presents a formidable challenge during the essential high-temperature annealing process. Herein, a facile and generally applicable VOx matrix confinement strategy is demonstrated for the controllable synthesis of ordered L10-PtM (M = Fe, Co, and Mn) nanoparticles, which not only enhances the dispersion of intermetallic nanocrystals, even at high loading (40 wt%), but also simplifies the oxide removal and acid-washing procedures. Taking intermetallic PtCo as an example, the as-prepared catalyst displays a high-performance oxygen reduction activity (mass activity of 1.52 A mgPt -1) and excellent stability in the membrane electrode assemblies (MEAs) (the ECSA has just 7% decay after durability test). This strategy provides an economical and scalable route for the controlled synthesis of Pt-based intermetallic catalysts, which can pave a way for the commercialization of fuel cell technologies.

PtAu Thin Film as Anode Electrocatalyst in Methanol Fuel Cell

PtAu Thin Film as Anode Electrocatalyst in Methanol Fuel Cell

Nanoporous Copper–Metal Organic Framework Microneedles on Nickel Foam as a Bifunctional Electrocatalyst for Glycerol Fuel Cell and Electrochemical Glycerol Detection in Biodiesel

Nanoporous Copper–Metal Organic Framework Microneedles on Nickel Foam as a Bifunctional Electrocatalyst for Glycerol Fuel Cell and Electrochemical Glycerol Detection in Biodiesel

Impact of Heat Treatment on the Oxygen Reduction Reaction Performance of PtCo/C(N) Electrocatalyst in PEM Fuel Cell

AbstractThe synthesis of efficient and stable Pt alloy catalysts is a major challenge for the commercialization of PEMFC. Herein, we report a PtCo/C(N) electrocatalyst prepared by Na2CO3‐assisted urea liquid‐phase deposition strategy as an efficient cathodic oxygen reduction reaction electrocatalyst, and test its activity and stability in a rotating disc electrode and a single‐cell. The membrane electrode prepared with PtCo/C(N)‐800 °C catalyst has an output voltage of 0.652 V at 2 A/cm2 and a maximum power density of 1.501 W/cm2, which are 36 mV and 81 W/cm2 higher than those of commercial Pt/C catalyst, respectively. In addition, the mass activity and half‐wave potential of PtCo/C(N)‐800 °C are 2.44 times and 50 mV higher than those of commercial Pt/C, respectively. After 5000 voltammetric cycles, its mass activity and half‐wave potential only lose 35 A/gPt and 9 mV, respectively. XPS results show that the binding energy of Pt 4f is positively shifted relative to Pt/C‐TKK, and the d‐band center of Pt decreases, leading to weak chemical interaction between the oxygen‐containing intermediate and the surface of the electrocatalyst, which is conducive to the improvement of the ORR activity and stability of the catalyst.

Research progress of metal oxide supports for fuel cells electrocatalysts

AbstractFuel cell technology, as a new way of energy conversion, is widely used in various fields. At present, the electrocatalyst, as one of the key components of the electrochemical reaction of fuel cells, still suffers from the problems of high cost, low activity and poor stability. Excellent fuel cell electrocatalysts must have excellent catalytic activity, anti‐poisoning ability, electrical conductivity and stability. Metal oxides with corrosion resistance, electrochemical stability and strong metal support interaction effects have been intensively studied. The influence of the synthesis method on the catalytic performance is also crucial. In this review, the importance of fuel cells and their catalysts is introduced. The characteristics of catalysts with three metal oxides, titanium dioxide, cerium dioxide and tungsten oxide, as supports, preparation methods and applications in different fuel cells are reviewed. The synthesis of metal oxide supported catalysts by impregnation, precipitation and hydrothermal methods is described. Finally, the research on metal oxide supported catalysts is prospected.

CO-Tolerant Hydrogen Oxidation Electrocatalysts for Low-Temperature Hydrogen Fuel Cells.

The severe performance degradation of low-temperature hydrogen fuel cells upon exposure to trace amounts of carbon monoxide (CO) impurities in reformate hydrogen fuels is one of the challenges that hinders their commercialization. Despite significant efforts that have been made, the CO-tolerance performance of electrocatalysts for the hydrogen oxidation reaction (HOR) is still unsatisfactory. This Perspective discusses the path forward for the rational design of CO-tolerant HOR electrocatalysts. The fundamentals of the CO-tolerant mechanisms on commercialized platinum group metal (PGM) electrocatalysts via either promoting CO electrooxidation or weakening CO adsorption are provided, and comprehensive discussions based on these strategies are presented with typical examples. Given the recent progress, some emerging strategies, including blocking CO diffusion with a barrier layer and developing non-PGM HOR catalysts, are also discussed. We conclude with a discussion of the strengths and limitations of these strategies along with the perspectives of the major challenges and opportunities for future research on CO-tolerant HOR electrocatalysts.

Phosphorus doped PdMo bimetallene as a superior bifunctional fuel cell electrocatalyst

The commercialization of direct alcohol fuel cells (DAFCs) relies on the development of high performance electrocatalysts for both the alcohol oxidation reaction and the oxygen reduction reaction (ORR). In this study, a novel phosphorus-doped palladium-molybdenum (P-PdMo) bimetallene with a partially amorphous structure is demonstrated. The ultrathin and curved morphology of the nanosheets, combined with electronic regulation by phosphorus atoms, facilitates OH adsorption and CO desorption. Consequently, the catalyst exhibits significantly enhanced activity and durability in the electrooxidation of alcohols, including methanol, ethanol, ethylene glycol, and glycerol. Particularly toward ethanol oxidation, the P-PdMo bimetallene displays exceptional mass and specific activities up to 4.95 A mg-1Pd and 8.28 mA cm−2, respectively. Furthermore, the P-PdMo bimetallene demonstrates outstanding ORR performance, with an onset potential of 1.0 V and a half-wave potential of 0.88 V. Overall, this study opens new avenues in metallene electrocatalysts and advancing toward the practical implementation of DAFCs.

Atomically Dispersed Zn/Co-N-C as ORR Electrocatalysts for Alkaline Fuel Cells.

Hydrogen fuel cells have drawn increasing attention as one of the most promising next-generation power sources for future automotive transportation. Developing efficient, durable, and low-cost electrocatalysts, to accelerate the sluggish oxygen reduction reaction (ORR) kinetics, is urgently needed to advance fuel cell technologies. Herein, we report on metal-organic frameworks-derived nonprecious dual metal single-atom catalysts (SACs) (Zn/Co-N-C), consisting of Co-N4 and Zn-N4 local structures. These catalysts exhibited superior ORR activity with a half-wave potential (E1/2) of 0.938 V versus RHE (reversible hydrogen electrode) and robust stability (ΔE1/2 = -8.5 mV) after 50k electrochemical cycles. Moreover, this remarkable performance was validated under realistic fuel cell working conditions, achieving a record-high peak power density of ∼1 W cm-2 among the reported SACs for alkaline fuel cells. Operando X-ray absorption spectroscopy was conducted to identify the active sites and reveal catalytic mechanistic insights. The results indicated that the Co atom in the Co-N4 structure was the main catalytically active center, where one axial oxygenated species binds to form an Oads-Co-N4 moiety during the ORR. In addition, theoretical studies, based on a potential-dependent microkinetic model and core-level shift calculations, showed good agreement with the experimental results and provided insights into the bonding of oxygen species on Co-N4 centers during the ORR. This work provides a comprehensive mechanistic understanding of the active sites in the Zn/Co-N-C catalysts and will pave the way for the future design and advancement of high-performance single-site electrocatalysts for fuel cells and other energy applications.

Molybdenum–Based Electrocatalysts for Direct Alcohol Fuel Cells: A Critical Review

<p>Direct alcohol fuel cells (DAFCs) have gained much attention as promising energy conversion devices due to their ability to utilize alcohol as a fuel source. In this regard, Molybdenum-based electrocatalysts (Mo-ECs) have emerged as a substitution for expensive Pt and Ru–based co-catalyst electrode materials in DAFCs, owing to their unique electrochemical properties useful for alcohol oxidation. The catalytic activity of Mo-ECs displays an increase in alcohol oxidation current density by several folds to 1000–2000 mA mg<sub>Pt</sub><sup>−1</sup>, compared to commercial Pt and PtRu catalysts of 10–100 mA mg<sub>Pt</sub><sup>−1</sup>. In addition, the methanol oxidation peak and onset potential have been significantly reduced by 100–200 mV and 0.5–0.6 V, respectively. The performance of Mo-ECs in both acidic and alkaline media has shown the potential to significantly reduce the Pt loading. This review aims to provide a comprehensive overview of the bifunctional mechanism involved in the oxidation of alcohols and factors affecting the electrocatalytic oxidation of alcohol, such as synthesis method, structural properties, and catalytic support materials. Furthermore, the challenges and prospects of Mo-ECs for DAFCs anode materials are discussed. This in-depth review serves as valuable insight toward enhancing the performance and efficiency of DAFC by employing Mo-ECs.</p>

Use of commercial TiO2 as direct ethanol fuel cell electrocatalyst support

Direct ethanol fuel cells (DEFCs) are efficient converters of chemical energy into electrical energy. DEFCs operate at low temperatures, and an anode, a cathode and an electrolyte are the main constituents. In alkaline media, electrocatalysts, responsible for promoting anodic and cathodic reactions, are generally composed of palladium supported on carbon black. Other materials have been studied in order to make the ethanol oxidation reaction (EOR) more efficient. In this work, the effect of commercial TiO2 as alternative support to Pd-based catalysts for the EOR was evaluated. The synthesized materials were characterized by X-ray diffraction, linear voltammetry and chronoamperometry, aiming to determine the effect of different supports on the performance of the EOR.

The role of high-resolution transmission electron microscopy and aberration corrected scanning transmission electron microscopy in unraveling the structure-property relationships of Pt-based fuel cells electrocatalysts.

Platinum-based fuel cell electrocatalysts are structured on a nano level in order to extend their active surface area and maximize the utilization of precious and scarce platinum. Their performance is dictated by the atomic arrangement of their surface layers atoms via structure-property relationships. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) are the preferred methods for characterizing these catalysts, due to their capacity to achieve local atomic-level resolutions. Size, morphology, strain and local composition are just some of the properties of Pt-based nanostructures that can be obtained by (S)TEM. Furthermore, advanced methods of (S)TEM are able to provide insights into the quasi-in situ, in situ or even operando stability of these nanostructures. In this review, we present state-of-the-art applications of (S)TEM in the investigation and interpretation of structure-activity and structure-stability relationships.

Local structures and robust oxygen reduction performances of TiN-supported bimetallic Pt–Cu electrocatalysts for fuel cells

The local structures and oxygen reduction reaction (ORR) performances of Pt–Cu fuel-cell electrocatalysts on robust TiN nanoparticles were investigated.

(Invited) The More Elements the Better? Studying Structure-Function Relations in High Entropy Alloy Nanoparticles As Fuel Cell Electrocatalysts

Low-temperature polymer electrolyte membrane fuel cells (PEMFCs), which convert chemical energy into electricity, are widely considered a suitable, sustainable technology to replace conventional combustion engines. However, fundamental issues such as fuel cell efficiency and durability still leave room for improvement, which could be achieved by finding more active and stable fuel cell electrocatalysts.[1] High entropy alloys (HEA) – solid solutions of five or more elements - are an emerging material class in the development of novel electrocatalysts. These multi-metallic compounds provide exciting new possibilities for catalyst design.[2] Recent theoretical analyses predict a great potential for HEAs as fuel cell catalysts due to the almost unlimited number of unique surface sites, which enables a wide distribution of adsorption energies. By changing the composition, the distribution of adsorption energies can be tailored toward the optimal binding energies of the catalytic intermediates.[3] The field of high entropy alloy catalysis enables a new, statistical approach to materials design. From an experimental viewpoint, however, HEAs come with new challenges regarding their synthesis and characterization.While HEA nanoparticles are essential for efficient catalysis to provide sufficiently large surfaces, their synthesis is only in its infancy. For a direct comparison between theoretically predicted properties and the performance of the prepared catalysts, single-phase HEA nanoparticles are essential.[4] Through studies of the synthesis pathways and in-depth structural characterization of the HEA nanoparticles with synchrotron X-ray techniques, it is possible to prepare model single-phase HEA nanoparticle catalysts. These well-mixed, multi-metallic materials allow us to study not only the different structure-activity properties of HEA nanoparticle fuel cell catalysts but to also explore the stability of these novel materials under reaction conditions. Studying the dissolution and degradation behaviour of model HEA catalysts in an acidic environment, the mechanisms that underly the degradation of multi-metallic PEMFC catalysts are explored. By relating structural characterization techniques with electrochemical analyses,[5] we can address the question of which role element mixing can play in the activation and stabilization of new fuel cell catalysts.[1] Schroeder, J.; Pittkowski, R. K.; Du, J.; Kirkensgaard, J. J. K.; Arenz, M. J. Electrochem. Soc. 2022, 169, 104504.[2] Löffler, T., Ludwig, A., Rossmeisl, J, Schuhmann, W. Angew. Chem. Int. Ed. 2021, 60, 2-12.[3] Batchelor, T. A. A, Pedersen, J. K., Winther, S.H., Castelli, I.E., Jacobsen, K. W., Rossmeisl, J. Joule 2019, 3, 834-845.[4] Pittkowski, R.; Clausen, C. M.; Chen, Q.; Stoian, D.; van Beek, W.; Bucher, J.; Welten, R. L.; Schlegel, N.; Mathiesen, J. K.; Nielsen, T. M.; Rosenkranz, A. W.; Bojesen, E. D.; Rossmeisl, J.; Jensen, K. M. Ø.; Arenz, M. ChemRxiv, 2022, https://doi.org/10.26434/chemrxiv-2022-khw4t.[5] Schroeder, J.; Pittkowski, R. K.; Martens, I.; Chattot, R.; Drnec, J.; Quinson, J.; Kirkensgaard, J. J. K.; Arenz, M. ACS Catalysis 2022, 12, 2077–2085