Multi-element catalytic structures for fuel cells

Abstract

Catalyst structure consisting of several elements, comprising: an area formed from a first metallic material; a first core area formed from a second metallic material, wherein the first core area has interface contact with the area; and a second core area formed from a third metallic material, wherein the second core area has interface contact with the first core area, the catalyst structure consists of several elements platinum (Pt), a first metal M I , a second metal M II and a third metal M III comprises, the first metal being M I is set up to improve the catalytic activity of Pt, the second metal M II is designed to increase the stability of the multi-element catalyst structure and the third metal M IIIis arranged so that it forms the covalent bond between Pt, the first metal M I , the second metal M II and / or the third metal M III reinforced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a multi-element catalyst structure for fuel cells, for example polymer electrolyte membrane fuel cells. BACKGROUND

[0002] Fuel cells have proven to be a promising alternative energy source for vehicles and other transportation applications. Fuel cells utilize a renewable energy source, such as hydrogen. Furthermore, fuel cells operate without toxic emissions or greenhouse gases. One of the current limitations for the widespread adoption and use of this clean and sustainable technology is the relatively high cost of the fuel cell stack. A catalyst material (e.g., platinum as a catalyst material) is contained in the catalyst layer of both the anode and cathode of the fuel cell. The catalyst material is one of the most expensive components of the fuel cell stack.JP 2019 164 962 A describes a membrane-electrode assembly comprising an electrolyte membrane and a pair of electrode layers, wherein the pair of electrode layers comprises a pair of catalyst layers arranged to sandwich the electrolyte membrane. US 2011 / 0 091 787 A1 discloses metal nanoparticle compositions containing metal or alloy and platinum particles for use in fuel cells. SUMMARY

[0003] According to one embodiment, a multi-element catalyst structure is disclosed. The multi-element catalyst structure has a region formed from a first metal material, a first core region formed from a second metal material, and a second core region formed from a third metal material. The first core region has interfacial contact with the region. The second core region has interfacial contact with the first core region. The multi-element catalyst structure comprises platinum (Pt), a first metal M I , a second metal M II and a third metal M III . The first metal M I is designed to improve the catalytic activity of Pt. The second metal M II is designed to increase the stability of the multi-element catalyst structure. The third metal M IIIis designed to form the covalent bond between Pt, the first metal M I , the second metal M II and / or the third metal M III reinforced.

[0004] According to another embodiment, a multi-element catalyst structure is disclosed. The multi-element catalyst structure has a region formed from a first metal material, a first core region formed from Pt, and a second core region formed from Co. The first core region has interfacial contact with the region. The second core region has interfacial contact with the first core region. The first metal material is selected from the group consisting of Mg, Sc, Y, Zr, and Hf.

[0005] In another embodiment, a fuel cell is disclosed. The fuel cell includes a polymer electrolyte membrane (PEM). The fuel cell also includes first and second electrode catalyst layers comprising first and second supports and first and second catalyst materials, respectively. The PEM is located between the first and second electrode catalyst layers. The first and / or second catalyst material includes a plurality of multi-element catalyst particles. Each of the plurality of catalyst particles includes a region formed from a first metal material, a first core region formed from a second metal material, and a second core region formed from a third metal material. The first core region is in interfacial contact with the region. The second core region is in interfacial contact with the first core region.The multi-element catalyst structure includes platinum (Pt), a first metal M. I , a second metal M II and a third metal M III . The first metal M I is designed to improve the catalytic activity of Pt. The second metal M II is designed to increase the stability of the multi-element catalyst structure. The third metal M III is designed to form the covalent bond between Pt, the first metal M I , the second metal M II and / or the third metal M III reinforced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a simplified side view of a fuel cell. Fig. 2 is a simplified graphical representation of a computing platform that may be used to implement DFT algorithms, calculations, and / or methods according to one or more embodiments. Fig. Figures 3A to 3F show simplified views of different catalyst layer structures for fuel cells. Fig. Figures 4A to 4F show simplified views of Co-doped Pt catalyst models for fuel cells. Fig. Figures 5A to 5J show simplified views of catalyst layer models using DFT calculations. Fig. Figure 6A shows a Pourbaix diagram graphically depicting the thermodynamic equilibrium states of a metal (tin) polymer electrolyte (PEM) system. Fig. Figure 6B shows a graphical representation showing calculated DFT results for ten different metals (M = cobalt (Co), nickel (Ni), rhenium (Re), tungsten (W), molybdenum (Mo), germanium (Ge), tin (Sn), niobium (Nb), tantalum (Ta), and titanium (Ti)) embedded in the Pt-M catalyst at different locations in a catalyst layer. Fig. Figure 7 shows a periodic table with the electronegativity of several elements. Fig. 8A to 8I show simplified side views of multi-element catalyst structures configured for use in electrode catalyst layers of fuel cells according to one or more embodiments. DETAILED DESCRIPTION

[0006] Embodiments of the present disclosure are described herein. It should be understood, however, that the disclosed embodiments are merely examples, and further embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or reduced to show details of particular components. Specific details of structure and function disclosed herein are therefore not to be interpreted as limiting, but merely as a representative basis by which one skilled in the art may variously utilize the embodiments.Those of ordinary skill in the art will understand that various features illustrated and described with respect to any of the figures may be combined with features illustrated in one or more additional figures to create embodiments not explicitly illustrated or described. The illustrated feature combinations provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure may be desirable for particular applications or implementations.

[0007] Except in the examples or where otherwise expressly stated, all numerical quantities in this specification indicating amounts of material or conditions of reaction and / or use are to be understood as being modified by the word "about" and thus describing the broadest scope of the invention. In general, practice within the specified numerical limits is preferred. In addition, unless expressly stated otherwise, percent, "parts of," and ratios are by weight; the term "polymer" includes "oligomer," "copolymer," "terpolymer," and the like; the description of a group or class of materials as suitable or preferred for a particular purpose in connection with the invention implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred;a molar mass given for any polymer refers to the number average molar mass; the description of ingredients refers chemically to the ingredients at the time of addition to any combination specified in the description and does not necessarily exclude chemical interactions among the ingredients of a mixture once mixed; the first definition of an acronym or other abbreviation applies to all subsequent uses of the same abbreviation in this document and applies by analogy to regular grammatical variants of the abbreviation defined at the outset; and unless expressly stated otherwise, the measured value of a property is determined by the same method as previously or subsequently given for the same property.

[0008] This invention is not limited to the specific embodiments and methods described below, as specific components and / or conditions may, of course, vary. Furthermore, the terminology used herein is for the purpose of describing embodiments of the present invention only and is not intended to be limiting in any way.

[0009] The singular form "a," "an," "the," and "the," when used in the description and the appended claims, includes plural referents unless the context clearly indicates otherwise. For example, when referring to a component in the singular, a plurality of components is considered included.

[0010] The term "substantially" may be used herein to describe disclosed or claimed embodiments. The term "substantially" may modify a value or relative property disclosed or claimed in the present disclosure. In these cases, "substantially" may mean that the value or relative property it modifies is within ± 0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, or 10% of the value or relative property.

[0011] Due to increasing carbon dioxide emissions and the relatively high current dependence on non-renewable fossil fuels as energy sources in the transport sector, the need for the development and commercialization of transport technologies that utilize clean and sustainable energy sources is steadily increasing. One promising technology is the fuel cell (including polymer electrolyte membrane fuel cells (PEMFC)). A fuel cell uses oxygen from the air and compressed hydrogen as fuel sources, but releases only water and heat. With the widespread use of fuel cells, carbon dioxide emissions would decrease. However, for widespread use, further efforts are needed to reduce the costs of catalysts (i.e., platinum catalysts) used in fuel cells.

[0012] A typical single fuel cell is constructed from a polymer electrolyte membrane (PEM), an anode layer, a cathode layer, and gas diffusion layers. These components form a membrane electrode assembly (MEA) surrounded by two flow field plates. Of all the MEA components, the catalyst, found in both the anode and cathode layers, is typically the most expensive component because platinum (Pt) must be used at both the anode and cathode layers, and there is no opportunity to reduce its cost through economies of scale. The most commonly used catalyst materials for PEMFCs in the industry are pure Pt, Pt-Co, and Pt-Ni nanoparticles.

[0013] Platinum catalysts dissolve and Pt 2+Ions migrate from the catalyst layer to other components in the fuel cell, such as the polymer electrolyte membrane (PEM). At the anode, Pt catalyzes a hydrogen oxidation reaction (HOR, H2 → 2H+ + 2e-), and at the cathode, Pt catalyzes the oxygen reduction reaction (ORR, 1 / 2O2 + 2H+ + 2e- → H2O). The required Pt loading is significantly higher at the cathode than at the anode, since the kinetics of the ORR are significantly slower than those of the HOR. Even when using a loading of only 0.025 mg Pt / cm 2 At the anode, the HOR can continue with kinetic losses of less than 20 mV. Alternatively, the kinetic loss in the ORR is 0.1 to 0.4 mg Pt / cm, even when using a significantly higher platinum loading. 2At currents appropriate for FCV operation, approximately ~400 mV. During fuel cell operation, Pt at both the anode and cathode can undergo further degradation (e.g., dissolution, migration, and redeposition, which can lead to loss of the electrochemically active surface), which would then increase the kinetic overpotentials experienced by the entire PEMFC stack system throughout its lifetime.

[0014] A PEMFC stack can typically degrade over time due to several different possible factors (e.g., flooding, catalyst degradation, corrosion from acidic environments, material failure, buildup of overvoltages, etc.). Operating PEMFCs at higher voltages above 0.8 V can generate more power for the stack system, but can cause the catalyst (and other components) to degrade more rapidly.

[0015] There is a need for a solution to reduce dissolution and slow migration while maintaining the beneficial activity of the platinum catalyst. Aspects of the present disclosure are directed to multi-element nanoparticle catalysts to reduce the amount of active catalyst for lower degradation and higher stability by creating new heterogeneous catalysts. The use of heterogeneous catalysts preserves the electrochemically active surface area (ECSA) and / or mitigates PEM degradation, thereby extending the lifetime of the fuel cell stack for a given catalyst loading.

[0016] Fig.Figure 1 shows a simplified side view of a fuel cell 10. The individual fuel cells 10 can be stacked on top of each other to form a fuel cell stack. The fuel cell 10 includes a polymer electrolyte membrane (PEM) 12, an anode layer 14, a cathode layer 16, and first and second gas diffusion layers (GDL) 18 and 20. The PEM 12 lies between the anode layer 14 and the cathode layer 16. The anode layer 14 lies between the first GDL 18 and the PEM 12, and the cathode layer 16 lies between the second GDL 20 and the PEM 12. The PEM 12, the anode 14, the cathode 16, and the first and second GDLs 18 and 20 form a membrane electrode assembly (MEA) 22. The first and second sides 24 and 26 of the MEA 22 are bounded by flow fields 28 and 30, respectively. The flow field 28 supplies H2 to the MEA 22, as indicated by arrow 32. The flow field 30 supplies O2 to the MEA 22, as indicated by arrow 34.A catalyst material such as platinum is used in the anode layer 14 and the cathode layer 16. The catalyst material is typically the most expensive component of the MEA 22. The catalyst material is supported on a catalyst carrier.

[0017] In one embodiment, ab initio density functional theory (DFT) algorithms, calculations, and / or methods are used to determine a thermodynamic reaction pathway of an ORR occurring at a catalyst surface. The DFT algorithms can be used to model an oxygen atom adsorbed on a Pt catalyst and its reduction to OH, as well as the reaction with another H + (or H3O +), which can generate a water molecule (H2O). The modeling considers the strength of the chemical and / or physical bond for each adsorbate (-H, -OH, -O, and H2O) and how it potentially affects catalytic activity and stability.

[0018] The DFT algorithms, calculations, and / or methods of one or more embodiments are implemented using a computing platform such as the computing platform 50 described in Fig.2. The computing platform 50 may include a processor 52, a memory 54, and a non-volatile memory 56. The processor 52 may include one or more devices selected from high-performance computing (HPC) systems, including high-performance cores, microprocessors, microcontrollers, digital signal processors, microcomputers, central processing units, field-programmable logic gate arrays, programmable logic circuits, state machines, logic circuits, analog circuits, digital circuits, or any other devices that manipulate signals (analog or digital) based on computer-executable instructions located in the memory 54.Memory 54 may include a single memory device or multiple memory devices, including, but not limited to, random access memory (RAM), volatile memory, non-volatile memory, static random access memory (SRAM), dynamic random access memory (DRAM), flash memory, cache memory, or any other device capable of storing information. Non-volatile memory 56 may include one or more persistent data storage devices, such as a hard drive, an optical drive, a tape drive, a non-volatile solid-state storage device, cloud storage, or any other device capable of permanently storing information.

[0019] The processor 52 may be configured to read into the memory 54 and execute computer-executable instructions located in the DFT software module 58 of the non-volatile memory 56, which embody DFT slab model algorithms, calculations, and / or methods of one or more embodiments. The software module 58 may include operating systems and applications. The software module 58 may be compiled from or interpreted based on computer programs created using various programming languages ​​and / or technologies, including, but not limited to, Java, C, C++, C#, Objective C, Fortran, Pascal, Java Script, Python, Perl, and PL / SQL, either alone or in combination.

[0020] When executed by processor 52, the computer-executable instructions of DFT software module 58 may cause computing platform 50 to implement one or more of the DFT algorithms and / or methods disclosed herein. Non-volatile memory 56 may also include DFT data 60 usable for the functions, features, calculations, and methods of the one or more embodiments described herein.

[0021] The program code embodying the algorithms and / or methods described herein may be distributed individually or collectively as a program product in a variety of forms. The program code may be distributed using a computer-readable storage medium having computer-readable program instructions embodied thereon for causing a processor to perform aspects of one or more embodiments. Computer-readable storage media, which are inherently non-transitory, may include both volatile and non-volatile, as well as removable and non-removable tangible media employed in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data.Computer-readable storage media may further include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other electronic storage technology, portable compact disc read-only memory (CD-ROM) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be read by a computer. Computer-readable program instructions may be downloaded to a computer, other type of programmable data processing device, or other device from a computer-readable storage medium, or to an external computer or external storage device over a network.

[0022] Computer-readable program instructions stored on a computer-readable medium can be used to instruct a computer, other types of programmable data processing devices, or other devices to operate in a particular manner such that an article of manufacture is produced with the instructions stored on the computer-readable medium, including instructions that implement the functions, acts, and / or operations identified in the flowcharts or diagrams. In certain alternative embodiments, the functions, acts, and / or operations identified in the flowcharts and diagrams can be rearranged, processed sequentially, and / or processed concurrently, according to one or more embodiments.Moreover, each of the flowcharts and / or diagrams may include more or fewer nodes or blocks than illustrated, according to one or more embodiments.

[0023] The DFT software module 58 generated Fig. Figures 3A to 3F show simplified views of different catalyst layers and the effect of doping and substitution with Co on Pt as a catalyst on an ORR reaction (i.e., fuel cell potential). As shown by the DFT calculations, different chemical doping and / or substitution can significantly influence catalyst activity. The DFT software module 58 calculates results for an ORR reaction occurring with pure Pt and Pt-Co catalyst materials, with the Co atoms located at various locations within a Pt(111) catalyst slab. Fig.Figure 3C shows Co atoms located at site 100 of the Pt(111) catalyst slab 102. Fig. Figure 3D shows Co atoms located at sites 104 of the Pt(111) catalyst slab 102. Fig. Figure 3E shows Co atoms located at sites 106 of the Pt(111) catalyst slab 102. Fig. Figure 3F shows Co atoms located at sites 108 of the Pt(111) catalyst slab 102. As in Fig. As shown in Figure 3A, the DFT calculations show that in pure Pt at 0.74 V versus V RHE the following reaction takes place. Pt−OH+H++e−↔Pt+H2O

[0024] The catalyst layer 110 represents the reactant side of reaction (1) with the platinum atoms 112, the hydroxide ions 114 and the hydrogen ions 116. The catalyst layer 118 represents the product side of reaction (1) with the platinum atoms 112 and the water molecules 120. As in Fig.As shown in Figure 3B, the DFT calculations show that in pure Pt at 0.95 V versus V RHE the following reaction takes place. Pt−O+H++e−↔Pt+OH

[0025] According to DFT calculations, the potential of reactions (1) and (2) is increased when Co is substituted at site 100 or sites 104, which are located near the surface of the Pt(111) catalyst slab 102. According to DFT calculations, Co has a smaller effect when Co is substituted at sites 106 and 108, which are located in the bulk direction. For example, the Co located at site 106 shows a similar potential to that of Co located at site 100, despite the different Co concentration in the Pt catalyst. For Co located at site 108, the effect is negligible compared to pure Pt. Since Co located at sites 108 leads to the same potential as Co located at sites 106, a pure Pt catalyst can be replaced by Pt-Co alloys in which three layers of Pt are located on top of Co metals (e.g. Pt shell and Co core).In such embodiments, the catalyst material comprising Co can save Pt loading and costs while delivering the same performance as pure Pt. Table 1 below shows the reaction potentials for each type of Pt(111) catalyst (with and without Co): Table 1 catalyst Reaction (1) Reaction (2) Standard potential Pure Pt(111) 0,74 V 0,95 V Good agreement with experiment Doping with Co near the surface (ie 100) 0,84 V 0,98 V Increase of 0.1 V compared to reaction (1) Doping with Co (ie 104) 1,07 V 1,29 V Increase of -0.3 V compared to reaction (1) and (2) Doping with Co (ie 106) 0,84 V 0,97 V Similar (1) Doping with Co (ie 108) 0,72 V 0,93 V Similar to pure Pt

[0026] Depending on the facet distribution, concentration of one or more alloying constituents, and the alloy distribution in a Pt catalyst (e.g., surface, near-surface, or bulk), the catalytic activity and stability can be significantly influenced. The surface layer can be the outermost surface layer. The near-surface layer can be a layer immediately below the surface layer. Bulk layers can be the layers below the surface layer and the near-surface layer. In further embodiments, the surface layer and the near-surface layer can be the first three layers, since the surface may not be in perfect condition.

[0027] The DFT software module 58 generated Fig.4A to 4F show Co-doped Pt catalyst models 150, 152, 154, 156, 158, and 160, respectively. Catalyst model 150 has Co-doping at surface sites 162. Catalyst model 152 has Co-doping at near-surface site 164. Catalyst model 154 has Co-doping at a site 166 in a third layer. Catalyst model 156 has Co-doping at a site 166 in a fourth layer. Catalyst model 158 has Co-doping at a site 170 in a fifth layer. Catalyst model 160 has Co-doping in a bulk region 172. In a further embodiment, the Co doping can be replaced by Ni doping. In Table 2 below, the doping energy (ΔE Dotierung ) [eV / site] for Co and Ni using the calculated DFT values. Table 2 ΔE Dotierung [eV / Stelle] Ni doping Co-doping surface 0,226 0,580 Near the surface -0,306 -0,001 Third layer -0,257 0,037 Fourth layer -0,267 0,043 Fifth layer -0,239 0,054 volume -0,148 0,138

[0028] From the DFT calculated data it can be seen that the calculated doping energy (ΔE Dotierung ) for Ni is generally more "negative" compared to a Co-doped Pt system. Although the crystal structures of Ni and Pt are similar, as they are both face-centered cubic (fcc), Co in its normal state has a hexagonal closest packing (hcp) structure. If the crystal structure, size, and / or electron valence are similar, mixing is easier to achieve. The data calculated using DFT also confirm that due to the strong mixing of Ni and Pt, it can be more difficult to crystallize Ni atoms in the near-surface region of the Pt catalyst. If the calculated ΔE Dotierungbelow zero, mixing is favored. The results calculated using DFT show that Co tends to crystallize close to the surface of Pt(111), whereas Ni can be mixed throughout the Pt (except at the surface of Pt). As shown in Table 2, the relatively high positive values ​​for Ni and Co doping at the surface indicate that crystallization of Ni and Co towards the Pt surface is least favorable. Table 2 also shows that Ni and Co most advantageously occupy the near-surface region. The doping in further lower layers tends towards the bulk values.

[0029] Fig.5A to 5J show the catalyst layers 200, 202, 204, 206, 208, 210, 212, 214, 216, and 218, respectively, using DFT calculations. The catalyst layer 200 is a pure Pt(111) material with a surface-bound oxygen atom 220. The catalyst layer 202 comprises a doping with Ni 222 and a surface-bound oxygen atom 224. The catalyst layer 204 comprises Ni atoms in a near-surface region 226 and a surface-bound oxygen atom 228. The catalyst layer 206 comprises a doping with Co 230 and a surface-bound oxygen atom 232. The catalyst layer 208 comprises Co atoms in a near-surface region 234 and a surface-bound oxygen atom 236. The catalyst layer 210 is a pure Pt(111) material with oxygen atoms 238 bound in a near-surface region.The catalyst layer 212 comprises a doping with Ni 240 and oxygen atoms 242 bound in a near-surface region. The catalyst layer 214 comprises Ni atoms in a near-surface region 244 and oxygen atoms 246 bound in a near-surface region. The catalyst 216 comprises a doping with Co 248 and oxygen atoms 248 bound in a near-surface region. The catalyst 218 comprises Co atoms in a near-surface region 252 and oxygen atoms 254 bound in the near-surface region 252. Table 3 shows the oxygen binding energies (ΔE) calculated using DFT. Bindung,O ) for the pure Pt, Pt-Ni and Pt-Co systems shown. Table 3 ΔE Dotierung [eV / O] surface Near the surface Pt(111) -1,664 +1,374 doped with Ni -1,189 +0,555 Ni near-surface area -1,100 -0,407 doped with Co -1,146 +0,285 Co near-surface area -1,055 -0,992

[0030] Depending on the catalyst composition, the oxygen binding energies can be strongly influenced, leading to different catalytic activity and degradation. The ΔEBindung,O on a pure Pt(111) surface is -1.664 eV, whereas ΔE Bindung,O of Ni and Co-doped / substituted Pt(111) is between -1.0 and -1.2 eV. The increase in oxygen binding energies indicates that once adsorbed on the catalyst surface, oxygen atoms can also be more easily desorbed, leading to an increase in catalytic activity (and thus allowing H2O to be formed more easily). The ΔE Bindung,O on a near-surface region of pure Pt(111) is +1.374 eV, indicating that a considerable amount of energy is required for oxygen to penetrate and form in the near-surface region. However, as soon as doping and substitution with either Co or Ni occurs on the Pt catalyst, ΔE decreases. Bindung,Oconsiderable. This suggests that substrate oxides may form more advantageously if Pt and Co / Ni dissolution steps are more easily triggered, especially at the high working potential of PEMFCs. While doping and substitution with Ni and Co in Pt can improve catalytic activity, the stability of a Pt-M catalyst is not as advantageous compared to the pure Pt catalyst. In one or more embodiments, the catalytic activity (i.e., PEMFC performance), catalytic stability (i.e., PEMFC lifetime), and catalyst cost are optimized simultaneously.

[0031] Fig.Figure 6A shows a Pourbaix diagram 260, which graphically represents the thermodynamic equilibrium states of tin (Sn) as a function of different acidity values ​​and voltages. The Pourbaix diagram 260 plots the electrode potential of tin (Sn) in E(V) 262 relative to the pH 264 of the electrolyte. The Pourbaix diagram 260 shows that Sn is passivated to SnO2 when the pH is between 1 and 4 and the voltage fluctuates between 0 and 1 V (which characterizes an operating regime applicable to PEMFC operation). Apart from Co, Ni, and Re, other elements (W, Mo, Ge, Sn, Nb, Ta, and Ti) can form an oxide in this range: e.g., WO 3-x , MoO 3-x , GeO 2-x , SnO 2-x , Nb2O 5-y , Ta2O 5-y and TiO 2-x (where 0 ≤ x ≤ 2 and 0 ≤ y ≤ 5). Co, Ni and Re are likely to be converted to Co in this PEMFC operating regime. 2+ , Ni 2+ and ReO4- .

[0032] Fig.Figure 6B shows a plot 270 depicting calculated DFT results for ten different metals (M = Co, Ni, rhenium (Re), tungsten (W), molybdenum (Mo), germanium (Ge), tin (Sn), niobium (Nb), tantalum (Ta), and titanium (Ti)) embedded in the Pt-M catalyst at various locations in a catalyst layer. The plot 270 shows the crystallization tendency of Pt-M by plotting the mixing energy [eV / site] as the y-axis 272 relative to the distance from the surface of the catalyst layer as the x-axis 274. The lowest mixing energy for each metal is the lowest point on each metal curve. In general, positive values ​​for DFT mixing energies indicate phase formation, and negative values ​​suggest that mixing can be achieved. The magnitude of the mixing energies determines the strength or weakness of the mixing. Ti and Pt, for example, mix more strongly than Ni and Pt. Co, Ni, and Re can mix to form Co.2+ , Ni 2+ , ReO4 - ionized when they come into direct contact with the PEFMC environment. The other elements tend to passivate during the PEMFC operating regime, i.e., to form a stable oxide MO x .

[0033] As shown by the DFT calculations presented earlier in this document, Co and Ni are most favored near the surface. While the mixing energy is generally positive for Co (due to the difference in crystal structure), Ni preferentially mixes with Pt due to their similar crystal structure (i.e., the mixing energy is slightly below zero). Re also has a similarly high mixing energy to Co and Ni, but mixes preferentially more at the bulk level. The other Fig.The elements listed in Figure 6B mix relatively strongly compared to Ni, Co, and Re (i.e., very negative mixing energies). W and Mo exhibit similar evolutions, with bulk mixing with Pt being most favored. Ge and Sn exhibit the same evolutions, with surface mixing mostly favored (whereas overall mixing energies are rather negative). Nb and Ta mix strongly in the bulk, whereas Ti tends to remain near the surface.

[0034] How Fig.As confirmed in Figure 6B, a different element M in Pt-M can lead to different crystallization in the catalyst materials, each resulting in different catalytic activity and stability. For example, both Co and Ni can increase catalytic activity; however, Pt-Co and Pt-Ni could lead to faster degradation due to favorable oxide formation in the near-surface region and their tendency to ionize to Co. 2+ and Ni 2+ during operation of the PEMFC as soon as they are exposed to the surface. Fig. Figure 6B shows DFT calculations on Pt-Sn, where Sn crystallizes more towards the surface. While the oxygen binding energy on Pt-Sn is increased (not as much as Pt-Co or Pt-Sn), the catalytic activity increases, making H2O easier to form during PEMFC operation. At the same time, Sn is only passivated to SnO2, but dissolves more readily than Co. 2+ - or Ni2+ -Systems are unlikely to occur without further ado.

[0035] Against the background of Fig. According to the DFT calculations presented in Figures 3 to 6, the selection and interrelationship of materials can influence the performance, degradation, and lifetime of the PEMFC. In one or more embodiments, multi-element catalyst structures are disclosed that include three or more different metals besides platinum (Pt-M I -M II -M III ). The multi-element catalyst structures are designed for use in catalyst layers of PEMFCs. The size of each multi-element catalyst particle can be one of the following values ​​or in a range between any two of the following values: 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 100, 150, 200, and 250 nm.

[0036] In certain embodiments, M Ia metal that improves catalytic activity and is otherwise referred to as a catalytic activity enhancer. The metals M I include 3d, 4d, and 5d transition metals, including, but not limited to, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), Co, Ni, copper (Cu) (3d transition metals); Y and Zr (4d transition metals), and Hf and Re (5d transition metals). The metals M I are designed to influence the electronic structure of Pt and thus increase the catalytic activity. If a metal M I in the PEMFC environment (pH from 1 to 4; voltage from 0 to 1 V versus V RHE ), the metal M I ionized and dissolve into the solution (e.g. Ni 2+ , Mn 2+ , Fe 3+ , Co 2+ etc.).

[0037] In certain embodiments, M IIa metal that contributes to the stability of the multi-element catalyst and is otherwise referred to as a stability enhancer. Non-limiting examples of the metals M II include precious metals such as ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium (Ir) and gold (Au) and passivating metals such as W, Mo, Ge, Sn, Nb, Ta and Ti. A passivating metal can become a passivating oxide under oxidizing conditions (e.g. high voltage and / or high pH), but does not dissolve in the acidic environment under the operating conditions of a PEMFC. Depending on the local environment of the catalysts, W, Mo, Ge, Sn, Nb, Ta and Ti can form WO 3-x , MoO 3-x , GeO 2-x , SnO 2-x , Nb2O 5-y , Ta2O 5-y and TiO 2-x oxidize (where 0 ≤ x ≤ 2 and 0 ≤ y ≤ 5).

[0038] In certain embodiments, M IIIa metal that is designed to form a relatively strong covalent bond between Pt, M I , M II and a carrier material (e.g. carbon). The selection of the metal M III can be done, for example, by comparing the electronegativity. Fig. Figure 7 shows a periodic table of 300 elements with the electronegativity of several elements.

[0039] Metallic bonds often have very little or no electronegativity difference. If the electronegativity difference is above 1.7, it is very likely that an ionic bond is formed. A covalent bond typically forms below 1.7. A polar covalent bond typically forms between 0.3 and 1.7. For example, if M I Ni is and M IIGe (electronegativity for both 1.8), an element is selected which has an electronegativity (χ) such that 0.1 < χ < 1.5 or 2.1 < χ < 3.5. At the same time, the electronegativity difference to Pt (χ = 2.2) and C (χ = 2.5) is considered: 0.5 < χ < 1.9 or 2.5 < χ < 3.9 for Pt and 0.8 < χ < 2.2 or 2.8 < χ < 4.2 for C. In this embodiment, an element with an electronegativity of 0.8 < χ < 1.5 or 2.8 < χ < 3.5 can meet the criteria for forming a covalent bond with Pt, Ni, Ge and C. Although not many metals satisfy the upper limit of this condition (2.8 < χ < 3.5), some metals such as Mg (1.2), Sc (1.3), Y (1.2), Zr (1.4), Hf (1.3) and many others can satisfy the lower limit for this criterion. The value for M III selected metal can fulfill two tasks and thus either M I (higher activity) or M II(higher stability). For catalyst supports other than carbon, such as TiO2 and SnO2, the process for selecting M III modified based on electronegativity.

[0040] Fig. 8A to 8I show simplified side views of catalyst structures comprising multiple elements 350, 352, 354, 356, 358, 360, 362, 364, and 366, which are configured to be used in electrode catalyst layers of fuel cells according to one or more embodiments. As in Fig.8A to 8I, the multi-element catalyst structures 350, 352, 354, 356, 358, 360, 362, 364, and 366 are generally triangular in shape. In one or more embodiments, the shape of the multi-element catalyst structure may vary depending on the synthesis conditions and the interfacial energy between the elements. Non-limiting examples of shapes generally include ovoid, octagonal, triangular, rectangular, cubic, hexagonal, and combinations thereof. The shapes may be flattened along two of the three dimensions of the shapes. The multi-element catalyst particle may contain at least 1 atomic % of the metals M I , M II and M III The atomic % of metals M I , M II and M III can be less than 50 atomic%.

[0041] In one or more embodiments, as much exposed Pt and / or Pt-M as possible IIon the surface is desirable to increase the electrochemically active surface area (ECSA). In one or more embodiments, a low concentration of the metals M II exposed in a Pt matrix, since the metals M II does not lead to strong dissolution. The low concentration can be at one of the following values ​​or in a range between any two of the following values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, and 16.7 atomic %. A metal M I can increase the catalytic activity, but a metal M I dissolve in the acid (e.g. Ni 2+ , Co 2+ ). In further embodiments, the metals M I and M II together form a matrix in a core area of ​​the catalyst. A metal M IIIcan form a distinct interface with Pt with a stronger attraction to the catalyst support materials (e.g., carbon, TiO2, SnO2). Since they increase the interfacial contact with other elements, Pt, M I and M II for stronger formation of covalent network bonds in certain embodiments, this is desirable. The loading of the catalyst support with the multi-element catalyst material can be one of the following values ​​or in a range between any two of the following values: 0.01, 0.025, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mg catalyst / cm 2 .

[0042] Fig.8A shows a simplified side view of the multi-element catalyst structure 350 supported on the catalyst support layer 368. The multi-element catalyst structure 350 includes the region 386, the first core region 388, and the second core region 390. The region 386 is generally spherical. The first core region 388 is generally ovoid. The second core region 390 is generally ovoid. A portion of the region 386 directly contacts the catalyst support layer 368. The region 386 is configured to support the first and second core regions 388 and 390. A portion of the region 386 is in interfacial contact with the first core region 388 and the second core region 390. Portions of the first core region 388 and the second core region 390 are in interfacial contact with each other. The region 386, which is formed of a metal M III is formed, contacts the catalyst support layer 368 and Pt and the metals M I and MII . The area 386 can contain pure metal M III In other embodiments, the region 386 is made of the metal M in one of the following values ​​or in a range between any two of the following values III : 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent. The first core region 388 is formed from Pt. The first core region 388 may be pure Pt. In other embodiments, the first core region 388 consists of one of the following values ​​or in a range between any two of the following values ​​of Pt: 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent. The second core region 390 is formed from a matrix of the metals M I and M II formed. The atomic ratio of metal M I to metal M II in the second core area 390 may be at one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5.

[0043] Fig. Figure 8B shows a simplified side view of the multi-element catalyst structure 352 supported on the catalyst support layer 370. The multi-element catalyst structure 352 includes the region 392, the first core region 394, and the second core region 396. The region 392 is formed from two discontinuous regions, as shown in Fig.8B. Each of the non-continuous regions is generally spherical. The first core region 394 is generally ovoid-shaped. The second core region 396 is generally ovoid-shaped. A portion of the region 392 directly contacts the catalyst support layer 370. The region 392 is configured to support the first and second core regions 394 and 396. A portion of the region 392 is in interface contact with the first core region 394 and the second core region 396. Portions of the first core region 394 and the second core region 396 are in interface contact with each other. The region 392 is formed of a metal M III formed. The area 392 can contain pure metal M III In other embodiments, the region 392 is made of the metal M in one of the following values ​​or in a range between any two of the following values III: 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 99.5 atomic percent. A portion of the first core region 394 may directly contact the catalyst support layer 370. The first core region 394 is formed of Pt. The first core region may be pure Pt. In other embodiments, the first core region 394 is made of one of the following values ​​or in a range between any two of the following values: 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 99.5 atomic percent. A portion of the second core region 396 may directly contact the catalyst support layer 370. The second core region 396 is made of a matrix of the metals M I and M II formed. The atomic ratio of metal M I to metal M II in the second core area 396 may be at one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5.

[0044] Fig.8C shows a simplified side view of the multi-element catalyst structure 354 supported on the catalyst support layer 372. The multi-element catalyst structure 354 includes the region 398, the first core region 400, and the second core region 402. The region 398 is generally spherical. The first core region 400 is generally ovoid. The second core region 402 is generally ovoid. A portion of the region 398 directly contacts the catalyst support layer 372. The region 398 is configured to support the first and second core regions 400 and 402. A portion of the region 398 is in interfacial contact with the first core region 400 and the second core region 402. Portions of the first core region 400 and the second core region 402 are in interfacial contact with each other. The region 398 is formed of a metal M III formed. The area 398 can contain pure metal M IIIIn other embodiments, the region 398 is made of the metal M in one of the following values ​​or in a range between any two of the following values III : 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent. The first core region 400 is made of a matrix of Pt and metal M II The atomic ratio of Pt to metal M II in the first core region 400 can be one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5. The second core region 402 is made of a metal M I The second core region 402 may be pure metal M I In other embodiments, the region 402 consists of the metal M in one of the following values ​​or in a range between any two of the following values I : 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent.

[0045] Fig.Figure 8D shows a simplified side view of the multi-element catalyst structure 356 supported on the catalyst support layer 374. The multi-element catalyst structure 356 includes the region 404, the first core region 406, and the second core region 408. The region 404 is formed from two discontinuous regions, as shown in Fig.8D. Each of the non-continuous regions is generally spherical. The first core region 406 is generally ovoid-shaped. The second core region 408 is generally ovoid-shaped. A portion of region 404 directly contacts the catalyst support layer 374. The region 404 is configured to support the first and second core regions 406 and 408. A portion of the region 404 is in interface contact with the first core region 406 and the second core region 408. Portions of the first core region 406 and the second core region 408 are in interface contact with each other. The region 404 is formed of a metal M III formed. The region 404 may contain pure metal M III In other embodiments, the region 404 is made of the metal M in one of the following values ​​or in a range between any two of the following values III: 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 99.5 atomic percent. A portion of the first core region 406 may directly contact the catalyst support layer 374. The first core region 406 is formed from a matrix of Pt and metal M II The atomic ratio of Pt to metal M II in the first core region 406 may be one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75, and 1:0.5. A portion of the second core region 408 may directly contact the catalyst support layer 374. The second core region 408 is made of a metal M I The second core region 408 may be pure metal M I In other embodiments, the first core region 408 is made of the metal M in one of the following values ​​or in a range between any two of the following values I : 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent.

[0046] Fig.8E shows a simplified side view of the multi-element catalyst structure 358 supported on the catalyst support layer 376. The multi-element catalyst structure 358 includes the region 410, the first core region 412, and the second core region 414. The region 410 is generally egg-shaped. The first core region 412 is generally egg-shaped. The second core region 414 is generally egg-shaped. A portion of the region 410 directly contacts the catalyst support layer 376. The region 410 is configured to support the first and second core regions 412 and 414. A portion of the region 410 is in interfacial contact with the first core region 412 and the second core region 414. Portions of the first core region 412 and the second core region 414 are in interfacial contact with each other. The area 410 is made of a matrix of the metals M I and M III formed. The atomic ratio of metal M II to metal MIII in region 410 may be at one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75, and 1:0.5. The first core region 412 may be pure Pt. In other embodiments, the first core region 412 may consist of Pt at one of the following values ​​or in a range between any two of the following values: 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 99.5 atomic percent. The second core region 414 may be pure metal M I In other embodiments, the second core region 414 is made of the metal M in one of the following values ​​or in a range between any two of the following values I : 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent.

[0047] Fig.8F shows a simplified side view of the multi-element catalyst structure 360 ​​supported on the catalyst support layer 378. The multi-element catalyst structure 360 ​​includes the region 416, the first core region 418, and the second core region 420. The region 416 is generally ovoid-shaped. The first core region 418 is generally ovoid-shaped. The second core region 420 is generally spherical. A portion of the region 416 directly contacts the catalyst support layer 378. The region 416 is configured to support the first and second core regions 418 and 420. A portion of the region 416 is in interfacial contact with the first core region 418. Portions of the first core region 418 and the second core region 420 are in interfacial contact with each other. The region 416 is formed from a matrix of the metals M I and M III formed. The atomic ratio of metal M II to metal M IIIin the region 416 can be one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5. The first core region 418 is made of a matrix of Pt and metal M II The atomic ratio of Pt to metal M II in the first core region 418 may be one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75, and 1:0.5. The second core region 420 may be pure metal M I In other embodiments, the second core region 420 is made of the metal M in one of the following values ​​or in a range between any two of the following values I : 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent.

[0048] Fig.8G shows a simplified side view of the multi-element catalyst structure 362 supported on the catalyst support layer 380. The multi-element catalyst structure 362 includes the region 422, the first core region 424, and the second core region 426. The region 422 is generally spherical. The first core region 424 is generally ovoid. The second core region 426 is generally spherical. A portion of the region 422 directly contacts the catalyst support layer 380. The region 422 is configured to support the first and second core regions 424 and 426. A portion of the region 422 is in interfacial contact with the first core region 424. Portions of the first core region 424 and the second core region 426 are in interfacial contact with each other. The region 422 may comprise pure metal M IIIn other embodiments, the second core region 426 is made of the metal M in one of the following values ​​or in a range between any two of the following values II : 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent. The first core region 424 is made of a matrix of Pt and metal M II The atomic ratio of Pt to metal M II in the first core region 424 can be one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5. The second core region 426 is made of a matrix of the metals M I and M II formed. The atomic ratio of metal M I to metal M II in the second core area 426 may be at one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5.

[0049] Fig.8H shows a simplified side view of the multi-element catalyst structure 364 supported on the catalyst support layer 382. The multi-element catalyst structure 364 includes the region 428, the first core region 430, and the second core region 432. The region 428 is generally ovoid-shaped. The first core region 430 is generally ovoid-shaped. The second core region 432 is generally spherical. A portion of the region 428 directly contacts the catalyst support layer 382. The region 428 is configured to support the first and second core regions 430 and 432. A portion of the region 428 is in interfacial contact with the first core region 430. Portions of the first core region 430 and the second core region 432 are in interfacial contact with each other. The region 428 is formed from a matrix of the metals M I and M III formed. The atomic ratio of metal M II to metal M IIIin the region 428 can be one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5. The first core region 430 is made of a matrix of Pt and metal M II The atomic ratio of Pt to metal M II in the first core region 430 can be one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5. The second core region 432 is made of a matrix of the metals M I and M II formed. The atomic ratio of metal M I to metal M II in the second core area 432 may be at one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5.

[0050] Fig.8I shows a simplified side view of the multi-element catalyst structure 366 supported on the catalyst support layer 384. The multi-element catalyst structure 366 includes the region 434, the first core region 436, and the second core region 438. The region 434 is generally ovoid-shaped. The first core region 436 is generally ovoid-shaped. The second core region 438 is generally spherical. A portion of the region 434 directly contacts the catalyst support layer 384. The region 434 is configured to support the first and second core regions 436 and 438. A portion of the region 434 is in interfacial contact with the first core region 436. Portions of the first core region 436 and the second core region 438 are in interfacial contact with each other. The region 434 is formed from a matrix of the metals M I and M III formed. The atomic ratio of metal M II to metal M IIIin region 434 can be at one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5. The first core region 436 can be pure Pt. In other embodiments, the first core region 436 consists of Pt at one of the following values ​​or in a range between any two of the following values: 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 and 99.5 atomic percent. The second core region 438 is made of a matrix of the metals M I and M II formed. The atomic ratio of metal M I to metal M II in the second core area 438 may be at one of the following values ​​or in a range between any two of the following values: 0.5:1, 0.5:1, 1:1, 1:0.75 and 1:0.5.

[0051] In relation to the Fig.In the multi-element catalyst structures shown in Figures 8A through 8I, the atomic ratio of material in the region, the first core region, and the second core region 390 may be one of the following values ​​or a range between any two of the following values: 0.01:0.01:0.98, 0.01:0.98:0.01, 0.98:0.01:0.01, and 0.33:0.33:0.33. In certain embodiments, the second core region is partially embedded within the first core region, with a portion of the surface of the second core region exposed. In other embodiments, the second core region is fully embedded within the first core region, with no portion of the surface of the second core region exposed.

[0052] In one or more embodiments, scanning probe block copolymer lithography (SPBCL) is used to synthesize the multi-element catalyst structures. In the SPBCL process, lithographically defined polymer domes are used as nanoreactors to synthesize the multi-element catalyst structures.

Claims

[1] Multi-element catalyst structure comprising: a region formed from a first metal material; a first core region formed from a second metal material, the first core region having interface contact with the region; and a second core region formed from a third metal material, wherein the second core region has interface contact with the first core region, wherein the catalyst structure consists of several elements platinum (Pt), a first metal M I , a second metal M II and a third metal M III wherein the first metal M I designed to improve the catalytic activity of Pt, the second metal M II is designed to increase the stability of the multi-element catalyst structure and to support the third metal M IIIis designed to form the covalent bond between Pt, the first metal M I , the second metal M II and / or the third metal M III reinforced. [2] A multi-element catalyst structure according to claim 1, wherein the first metal material comprises the third metal M III is. [3] A multi-element catalyst structure according to claim 1, wherein the first metal material comprises a matrix of the second metal M II and the third metal M III is. [4] The multi-element catalyst structure according to claim 1, wherein the second metal material is platinum (Pt). [5] The multi-element catalyst structure according to claim 1, wherein the second metal material comprises a matrix of Pt and the second metal M II is. [6] A multi-element catalyst structure according to claim 1, wherein the third metal material comprises a matrix of the first metal M Iand the second metal M II is. [7] A multi-element catalyst structure according to claim 1, wherein the third metal material is the first metal M I is. [8] A multi-element catalyst structure according to claim 1, wherein the region is formed from two or more non-continuous partial regions. [9] A multi-element catalyst structure according to claim 1, wherein the first metal M I selected from the group consisting of: V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Hf and Re. [10] A multi-element catalyst structure according to claim 1, wherein the second metal M II selected from the group consisting of: Ru, Rh, Pd, Ag, Os, Ir, Au, W, Mo, Ge, Sn Nb, Ta and Ti. [11] A multi-element catalyst structure according to claim 1, wherein the third metal M III selected from the group consisting of: Mg, Sc, Y, Zr and Hf. [12] Multi-element catalyst structure comprising: a region formed from a first metal material; a first core region formed of Pt, the first core region having interface contact with the region; and a second core region formed of Co, wherein the second core region has interface contact with the first core region, wherein the first metal material is selected from the group consisting of Mg, Sc, Y, Zr and Hf. [13] The multi-element catalyst structure according to claim 12, wherein the first core region is formed of pure Pt and the second core region is formed of Co. [14] The multi-element catalyst structure of claim 12, wherein the second core region has interfacial contact with the region. [15] A multi-element catalyst structure according to claim 12, wherein the region is formed from two or more non-continuous partial regions. [16] Fuel cell, comprising: a polymer electrolyte membrane (PEM); a first and second electrode catalyst layer comprising a first and second support and a first and second catalyst material, respectively, wherein the PEM is located between the first and second electrode catalyst layer, wherein the first and / or second catalyst material comprises a plurality of multi-element catalyst particles, wherein each of the plurality of multi-element catalyst particles has a region formed from a first metal material, a first core region formed from a second metal material, and a second core region formed from a third metal material, wherein the first core region has interfacial contact with the region, the second core region has interfacial contact with the first core region, wherein the multi-element catalyst structure comprises platinum (Pt), a first metal M I , a second metal M II and a third metal M IIIwherein the first metal M I designed to improve the catalytic activity of Pt, the second metal M II is designed to increase the stability of the multi-element catalyst structure and to support the third metal M III is designed to form the covalent bond between Pt, the first metal M I , the second metal M II and / or the third metal M III reinforced. [17] The fuel cell according to claim 16, wherein the first catalyst material comprises the plurality of multi-element catalyst particles, and the region of each of the plurality of multi-element catalyst particles directly contacts the first support. [18] The fuel cell according to claim 16, wherein the first catalyst material comprises the plurality of multi-element catalyst particles and a second catalyst material of pure Pt. [19] The fuel cell according to claim 16, wherein the first catalyst material comprises the plurality of multi-element catalyst particles and a second catalyst material of a Pt-Co alloy. [20] The fuel cell according to claim 16, wherein the first catalyst material comprises the plurality of multi-element catalyst particles and a second catalyst material of a Pt-Ni alloy.

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