Enhancing the oxygen reduction reaction activity and durability of a solid oxide fuel cell cathode by surface modification of a hybrid coating

While (La_0.6Sr_0.4)_0.95Co_0.2Fe_0.8O_3-δ (LSCF) has been one of the most investigated materials for a long time, its relatively insufficient oxygen reduction reaction (ORR) activity and inherent performance degradation are still two main obstacles to its massive application on oxygen-ion conducting solid oxide fuel cell (SOFC). To solve those issues, a composite of Pr₆O₁₁ and NiO has been deposited on LSCF successfully via a facile infiltration method in this study. The modified LSCF cathode exhibits ∼30% lower polarization resistance than LSCF. The excellent performance promotion may be due to the synergistic effect of Pr₆O₁₁ and NiO on the LSCF surface. The distribution of relaxation time (DRT) analyses of electrochemical impedance spectra (EIS) in different oxygen partial pressure and long-term operation indicate that the performance enhancement is caused by the facilitated oxygen surface adsorption-dissociation process and suppression of Sr segregation on modified LSCF cathode, thus achieving a higher peak power density of 1.40 W cm⁻² at 800 °C and better long-term operation stability of only 3% voltage decline rate after 80 h operation. These results indicate that Pr₆O₁₁ and NiO composite modification is a promising method for improving the electrochemical performance of LSCF.     

Synergistically enhancing CO2-tolerance and oxygen reduction reaction activity of cobalt-free dual-phase cathode for solid oxide fuel cells

High-performance cathodes with adequate CO₂ tolerance are vital for further development of intermediate-temperature solid oxide fuel cells (IT-SOFCs). However, there is always a trade-off between CO₂ tolerance and oxygen reduction reaction (ORR) performance for single-phase cathodes. Here, we report a cobalt-free Ba_0.6La_0.4FeO_3-δ-Ce_0.8Sm_0.2O_2-δ (BLF-SDC) dual-phase cathode with excellent ORR activity and CO₂ tolerance. Introducing ionic conductor Ce_0.8Sm_0.2O_2-δ (SDC) into the Ba_0.6La_0.4FeO_3-δ (BLF) phase can boost ORR activity due to the extended active sites and enhanced oxygen surface exchange process with a polarization resistance of 0.121 Ω cm² for the BLF-30% SDC (weight ratio, BLF-30SDC) cathode at 700 °C. The CO₂ resistance of the BLF-30SDC composite cathode outperforms BLF cathode by three times at 600 °C. This stability enhancement is owing to low CO₂ adsorption of SDC, which is confirmed from thermodynamic calculation. This work indicates that dual-phase mixed conductors can be developed as highly active and stable cathodes for IT-SOFCs.     

Enhancing oxygen reduction activity and CO2-tolerance of A-site-deficient BaCo0.7Fe0.3O3-δ cathode by surface-decoration with Pr6O11 particles

Sluggish oxygen reduction reaction (ORR) activity and poor CO₂-tolerance has been the long-standing limitations for the application of alkaline earth metal oxide cathode for solid oxide fuel cells (SOFCs). Here we report this situation can be ameliorated with a composite cathode based on Ba_0.9Co_0.7Fe_0.3O_3-δ (B90CF) by surface-decorated Pr₆O₁₁ (PO) particles. A halved polarization resistance is obtained by B90CF-15PO (PO of 15 wt%) cathode (0.033 Ω cm² at 700 °C) compared to blank B90CF, suggesting boosted oxygen reduction reaction activity owing to the accelerated oxygen surface exchange kinetics introduced by PO particles. PO protective layer also brings up desirable CO₂-tolerance for B90CF cathode due to the more stable fluorite cubic structure of PO and higher acidity of Pr³⁺/Pr⁴⁺ than Ba²⁺_, which ensures the stable operation of cells. This work demonstrates the positive potential of surface-decoration with PO in developing cathodes with high performance and CO₂-tolerance.     

A novel dual phase BaCe0.5Fe0.5O3-δ cathode with high oxygen electrocatalysis activity for intermediate temperature solid oxide fuel cells

A novel iron-based perovskite BaCe_0.5Fe_0.5O_3-δ (BCF) powders were successfully fabricated and the phase composition, lattice structure, oxygen surface exchange coefficient and electrochemical performance were investigated. The ultrafine BCF powder with grain size of about 200 nm consisted of dual phase BaCe_0.15Fe_0.85O_3-δ and BaCe_0.85Fe_0.15O_3-δ. Electrical conductivity relaxation measurement illustrates the low conductivity activation energy and the high oxygen surface exchange kinetics with oxygen surface exchange coefficient of 3.8 × 10⁻⁵ cms⁻¹ at 600 °C. BCF cathode exhibits 1.04 Ωcm² on doped ceria electrolyte and remains stable in 400 h long term test at 600 °C. A single cell based on doped ceria electrolyte with BCF cathode shows a maximum power density of 228 mW cm⁻² at 650 °C. The preliminary results indicate that the dual phase BCF can be applied as cathode material for oxygen ion conductive solid oxide fuel cells.     

An oxygen reduction reaction active and durable SOFC cathode/electrolyte interface achieved via a cost-effective spray-coating

One of the critical obstacles for commercialization of solid oxide fuel cells (SOFCs) technology is to develop efficient interfaces between cathode and electrolyte that enable high activity toward oxygen reduction reaction (ORR) while maintain long-term durability. Here, we report a cost-effective spray-coating process that applied in the building of an ORR active and durable cathode/electrolyte interface. When tested at 750 °C, such spray-coated cathodes show a typical interfacial polarization resistance of ~0.059 Ωcm², much lower than that of ~0.10 Ωcm² for screen-printed cathodes. Detailed distribution of relaxation time analyses of the impedance spectra over time indicates that the capability of mass transfer and surface exchange process in the spray-coated cathode/electrolyte interface has been enhanced and maintained in the testing periods of ~100 h. As a result, a Ni-based anode supported cell with thin electrolyte and spray-coated cathodes shows an excellent peak power density of 1.012 Wcm⁻², much higher than that of 0.712 Wcm⁻² for cells with screen-printed cathodes, when tested at 750 °C using wet H₂ as fuel and ambient air as oxidant. It is demonstrated that ORR activity and durability of the SOFC cathodes can be dramatically enhanced via a cost-effective spray-coating process.     

Boosting electrocatalytic performance of Ruddlesden-Popper type Fe-based cathode catalysts by La and Ni co-doping for solid oxide fuel cells

Exploring advanced electrode materials with high electrochemical performance and sufficient durability is crucial to the commercialization of solid oxide fuel cells (SOFCs). Herein, a Ruddlesden-Popper Sr_2·9La_0·1Fe_1·9Ni_0·1O_7?δ (SLFN) oxide is systematically evaluated as efficient oxygen electrode material. La and Ni co-doping strategy demonstrates improved oxygen desorption ability and promoted electrochemical activity of pristine Sr₃Fe₂O_7?δ (SF) toward oxygen reduction react (ORR). Further, the ORR process of the SLFN electrode is probed by electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) technique. The button cell with the SLFN cathode delivers a peak power density of 1.01 W cm^?2 at 700 °C, along with desirable stability over a period of 60 h. This study offers a feasible strategy for developing Ruddlesden-Popper type cathode candidates for SOFCs.     

Design and research progress of nano materials in cathode catalysts of microbial fuel cells: A review

With the advantages of clean, efficient and energy-saving, microbial fuel cells (MFCs) were characterized with perfect significance in the field of degrading environmental pollutants and generating electricity meanwhile. The cathode materials affected the activity of oxygen reduction reaction (ORR), and affected the power generation performance for MFCs. There were many kinds of nano materials played an important role in the field of cathode catalysis. The advantages of metal and non-metal composites were easy to obtain and low cost; layered double hydroxide (LDH) was easy to control and compound, and could be fully realized functionalization; metal organic frameworks (MOFs) were widely used since their porosity, high specific surface area and high activity; covalent organic frameworks (COFs) were low density and easy to be modified, so as to modify and realize functionalization; MXene was an excellent two-dimensional material, which could provide more channels for the movement of ions. The nano materials formed by the composite of various materials combined the advantages of various materials and played key role in improving ORR performance of MFCs.     

Layered perovskite GdBaCoFeO5+x as cathode for intermediate-temperature solid oxide fuel cells

A layered perovskite oxide, GdBaCoFeO_5+x (GBCF), was investigated as a novel cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). A laboratory-sized Sm_0.2Ce_0.8O_1.9 (SDC)-based tri-layer cell of NiO–SDC/SDC/GBCF was tested under intermediate-temperature conditions of 550–650 °C with humidified H₂ (∼3% H₂O) as a fuel and the static ambient air as oxidant. A maximal power density of 746 mW cm⁻² was achieved at 650 °C. The interfacial polarization resistance was as low as 0.42, 0.18 and 0.11 Ω cm² at 550, 600 and 650 °C, respectively. The experimental results indicate that the layered perovskite GBCF is a promising cathode candidate for IT-SOFCs.     

Reduced graphene oxide-supported Pd@Au bimetallic nano electrocatalyst for enhanced oxygen reduction reaction in alkaline media

Rational design and synthesis of core-shell bimetallic nanoparticles with tailored structural and functional properties is highly sought to realize clean and energy-efficient fuel cell systems. Herein, PdAu bimetallic nanoparticles (NPs) with core-shell morphology (Pd_Core–Au_Shell) were fabricated on the surface of reduced graphene oxide (RGO) support by a facile two-step protocol. In the first step, Pd_Core–Ag_Shell bimetallic NPs were synthesized on RGO support by reducing Pd²⁺and Ag⁺ ions with methyl ammonia borane (MeAB). Later, Pd_Core–Au_Shell bimetallic NPs were conveniently fabricated on RGO support via a galvanic replacement strategy involving sacrificial oxidation of metallic silver and reduction of gold ions. The resulting core/shell bimetallic NPs were characterized by X-ray diffraction (XRD), High-resolution transmission electron microscopy (HR-TEM), Energy dispersive X-ray spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FT-IR) and cyclic voltrammetry (CV). The electrocatalytic performance of core/shell nanostructures for the room temperature oxygen reduction reaction (ORR) in alkaline media were systematically performed by CV. The electrode-area-normalized ORR activity of RGO-supported Pd_Core–Au_Shell NPs was higher than the corresponding commercially available carbon-supported Pt nanoparticles (Pt/C) at ?0.8 V vs Ag/AgCl (satd. KCl) (6.24 vs 5.34 mA cm^?2, respectively). Further, methanol-tolerant ORR activities of as-synthesized catalysts were also studied. The Au-on-Pd/RGO bimetallic NPs presented enhanced ORR activity both in presence and in the absence of methanol in comparison with a commercial Pt/C catalyst and as-synthesized Pd/RGO and Au/RGO catalysts. The enhanced catalytic activities of core/shell structures might be resulted owing to the optimized core/shell structure comprising of a small Pd core and a thin Au shell and synergistic effects offered by Pd and Au. The present synthesis protocol demonstrated for two-layer structure can be extended to multi-layered structures with desired functions and activities.     

Efficient synthesis of Pt3Co/NC alloy catalysts with enhanced durability and activity for the oxygen reduction reaction

Lack of catalytic performance, short life, and high cost are three main problems related to JM-Pt/C catalysts for proton exchange membrane fuel cells. The introduction of cheap transition metals improves catalytic performance while significantly reducing the cost of the catalysts. Here, we report the synthesis of Pt₃Co/NC alloy catalysts via coating and pyrolysis treatment. The agglomeration of nanoparticles during the high-temperature alloying process is significantly inhibited by coating with PANI. Remarkably, the obtained Pt₃Co/NC alloy catalysts exhibit excellent ORR catalytic performance and structural stability in 0.1 mol/L HClO₄. After 30,000 potential cycles, the mass activity and area-specific activity of Pt₃Co/NC alloy catalysts are 1.949 and 3.936 times higher, respectively, than that of JM-Pt/C with negligible performance loss. The strong metal-support interaction between N and Pt and the Pt-rich surface restrict the dissolution of Pt and Co, resulting in excellent stability. This synthesis approach provides an effective way to develop active and stable Pt alloy catalysts.     

Ruddlesden-Popper-based lanthanum cuprate thin film cathodes for solid oxide fuel cells: Effects of doping and structural transformation on the oxygen reduction reaction

Highly textured, c-axis oriented thin films of undoped, Ba-doped, and Sr-doped La₂CuO₄ are successfully prepared on YSZ (100) substrates by using pulsed laser deposition. Intriguingly, the films undergo a structural transformation from T′(square-planar) to T (octahedral) crystal structure with partial substitution of Ba and Sr ions on La site. Meanwhile, the addition of both Ba and Sr dopants lead to reducing in polarization resistance and alternative kinetics of oxygen reduction reaction (ORR), hereinto La_1·8Ba_0·2CuO₄ film presents superior electrochemical properties because it can accommodate much more oxygen vacancies than the other two films. First-principles calculations reveal that much lower O-defect formation energy originate fundamentally from the increase of Cu–O bond length along c-axis orientation after structural transformation from T′-phase to T-phase. These findings unveil the relationship between the structural transformation and ORR activity, and provide a novel approach to rational design film cathodes for higher electrochemical performance.     

Enhancing oxygen reduction reaction activity of perovskite oxides cathode for solid oxide fuel cells using a novel anion doping strategy

Possessing a high oxygen reduction reaction (ORR) activity is one of the most important prerequisites for the cathode to ensure an efficient solid oxide fuel cell. Herein, a highly active cathode is developed by doping the fluorine anion in anion sites of perovskite oxides (ABO₃). The electrocatalytic activities of three different cathode samples including the original perovskite La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF), the doped La_0.6Sr_0.4Co_0.2Fe_0.8O_2.95-δF_0.05 (LSCFF0.05) and La_0.6Sr_0.4Co_0.2Fe_0.8O_2.9-δF_0.1 (LSCFF0.1) are comparatively investigated. The fluorine doped perovskites reveal higher electrochemical performance than the original perovskite. Based on three cathodes of LSCF, LSCFF0.05 and LSCFF0.1 operated at 850 °C, the measured area specific resistance was 0.018, 0.017 and 0.91 Ω cm², respectively; and the respective maximum power density of the single fuel cell using the 9-μm-thick YSZ electrolyte was 754, 1005, and 737 mW cm^?2. Such performance results vividly indicate that, the obtained perovskite oxyfluoride by doping an optimum amount of F ions can efficiently improve ORR activity and thus is a feasible strategy to develop cathode for high-performance solid oxide fuel cells.     

Co and Hf co-doped BaFeO3 cathode with obviously enhanced catalytic activity and CO2 tolerance for solid oxide fuel cell

It is essential to develop efficient and stable cathode materials operated at intermediate temperature for the application of solid oxide fuel cell. In this work, BaFeO_3–δ based perovskite oxide was used to explore the influence of Co and Hf co-doping on the catalytic activity and CO₂ tolerance of SOFC cathode materials. Among the series materials, BaCo_0·2Fe_0.7Hf_0.1O_3–δ (BC2FHO) shows excellent catalytic activity and CO₂ stability. The EIS measurement shows that the polarization resistance (R_p) of BC2FHO is ～0.04 Ω cm² at 800 °C. In the CO₂ tolerance test, the R_p decreases to ～0.0435 Ω cm² within 1 h after removing 10% CO₂. The peak power density of the single cell with BC2FHO cathode are 1010.4, 649.4, and 256.6 mW cm^?2 at 800, 700, and 600 °C, respectively. And the total degradation rate of the output voltage at 700 °C is only 0.009% h^?1. The significantly enhanced activity and stability are attributed to Co and Hf co-doping. The incorporation of Hf allows BaFeO₃ to obtain a highly symmetrical cubic structure with increased oxygen ion transport channels, which is conducive to promote the oxygen reduction reaction. In addition, Hf-doping can also increase the acidity to make the material resistant to CO₂. The incorporation of Co improves the concentration of oxygen vacancies, which makes BC2FHO show excellent electrochemical performance.     

Zeolitic imidazolate framework ZIF-67 grown on NiAl-layered double hydroxide/graphene oxide as cathode catalysts for oxygen reduction reaction in microbial fuel cells

In this study, the cathode catalysts for microbial fuel cells (MFCs) were successfully synthesized by two-step feeding method. NiAl-layered double hydroxide (LDH) nanoparticle was attached efficiently on the surface of graphene oxide (GO) in situ, zeolitic imidazolate framework (ZIF-67) was modified on LDH surface layer; Highly crystalline NiAl-LDH/GO@ZIF-67 composite was flawlessly prepared, nano-hybrid had (003), (006), (011), (112) and (222) characteristic crystal planes attribute to NiAl-LDH/GO and ZIF-67 by X-ray diffraction (XRD), and the sheet-like structure and polyhedral structure were observed. The NiAl-LDH/GO@ZIF-67 nano-hybrid was rich in metal elements and provides a wealth of electrochemical active sites by EDS test. The study displayed that the maximum output voltage of NiAl-LDH/GO@ZIF-67-MFC was 516 mV and the stabilization time could last for about 8 d. The maximum output power was 501.26 mW/m², which was 1.31 times of NiAl-LDH/GO-MFC (381.92 mW/m²) and 2.76 times of ZIF-67-MFC (181.48 mW/m²). The GO with high conductivity was used as the substrate to ensure the stability of electrode cycle and the efficiency of power generation, the laminar structure of NiAl-LDH provided the specific surface area for the reaction, which facilitated the transport of electrons. The good structure of ZIF-67 increased the active sites of the composite. The excellent properties of the composites promoted the electrochemical stability and electricity production output of MFC. This study provided a method for the further application of MFC in the wastewater field.     

Alkaline metal doped strontium cobalt ferrite perovskites as cathodes for intermediate-temperature solid oxide fuel cells

Perovskite oxides Sr_0.9K_0.1Fe_xCo_1-xO_3-δ (SKFCx, x = 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) are investigated as potential cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) on Sm_0.2Ce_0.8O_1.9 (SDC) electrolyte. The cubic phase of the SKFCx oxides is demonstrated by x-ray diffraction. The SKFCx cathode shows good compatibility with the SDC electrolyte up to 900 °C. Among the investigated compositions, SKFC0.1 displays the highest electrical conductivity of 443–146 S·cm^?1 from 350 °C to 800 °C in flow air. The area specific resistances (ASRs) of the SKFCx (x = 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) cathodes are 0.047, 0.058, 0.066, 0.101, 0.155 and 0.175 Ω cm² at 650 °C in air on an SDC electrolyte. Among the five tested cathodes, SKFC0.1 exhibits the lowest area specific resistances between 550 °C and 750 °C, when tested on its symmetric cell configuration of cathode|SDC|cathode. The thermally stabilized cubic perovskite structure of the SKFC0.1 powder is demonstrated by high-temperature XRD. The average linear thermal expansion coefficient α_L of SKFC0.1 is 18.9$\times$10^?6 K^?1. A peak power density of 1643 mW·cm^?2 is achieved on SKFC0.1|SDC|Ni-SDC anode supported fuel cell at 650 °C. These features, and excellent electrocatalytic activity and good stability, indicate the potential of alkaline metal doped strontium cobalt ferrite perovskites are promising cathode materials for IT-SOFCs.     

Comparative study of Pd and PdO as cathodes for oxygen reduction reaction in intermediate temperature solid oxide fuel cells

Metallic Pd and PdO electrodes were prepared by using Pd and PdCl₂ slurries, respectively, and their electrochemical performance as a cathode for oxygen reduction reaction in intermediate temperature solid oxide fuel cells was evaluated by electrochemical impedance spectroscopy (EIS) and direct current polarization (DC polarization). The electrochemical activity of metallic Pd was much higher than that of PdO for the reaction of oxygen reduction; below the decomposition temperature, a thin layer of PdO formed on the surface of metallic Pd electrode, which increased its polarization resistance. The decomposition temperature of PdO decreased from 810 to 750 °C as oxygen partial pressure decreased from 20 to 5 kPa, and was further lowered under the influence of the applied current during DC polarization test. The charge transfer resistance of PdO increased by decreasing oxygen partial pressure, while that of metallic Pd was less sensitive to it.     

Three-dimensional ZIF-67 attached lamellar Ti3AlC2 combined with ZnAl-LDH as cathode catalyst for enhancing oxygen reduction reaction of microbial fuel cells

In this study, a simple hydrothermal method was used to prepare the cathode catalyst of microbial fuel cells (MFCs). The three-dimensional structure of ZIF-67 attached to the lamellar Ti₃AlC₂/ZnAl-layered double hydroxide (LDH) was observed. (010), (012), (015) were the obvious peaks of the composite ZIF-67@Ti₃AlC₂/ZnAl-LDH. Ti, N, C, Al, O, F were relatively uniformly distributed on the surface of the composite material. The maximum voltage of ZIF-67@Ti₃AlC₂/ZnAl-LDH-MFC was 576 mV and the stabilization time was 8 d. The maximum power density of ZIF-67@Ti₃AlC₂/ZnAl-LDH-MFC was 587 mW/m², which was 1.32 times of Ti₃AlC₂/ZnAl-LDH-MFC (446 mW/m²) and 2.69 times of Ti₃AlC₂-MFC (218 mW/m²). Ti₃AlC₂ with large interlayer spacing and high specific surface area were perfectly composited with multi-layer nanosheets of ZnAl-LDH, and ZIF-67 attached to the surface enhanced the reaction center and activity of the composite material, which promoted oxygen reduction reaction and improved MFC performances.     

Advanced electrocatalytic activity of praseodymium-deficient copper-based oxygen electrodes for solid oxide fuel cells

Herein praseodymium-deficient Pr_1.90−xCe_0.1CuO₄ oxides are evaluated as potential oxygen electrodes for solid oxide fuel cells (SOFCs). Introducing Pr-deficiency promotes the oxygen vacancy concentration, further improving electrocatalytic activity of the Pr_1.90−xCe_0.1CuO₄ electrodes towards oxygen reduction reaction (ORR). The Pr_1.75Ce_0·.1CuO₄ (P_1·75CC) component exhibits outstanding electrode performance, as supported by a polarization resistance as low as 0.025 Ω cm² and high peak power density of the single cell (1.11 W cm⁻²) at 700 °C. In addition, the rate-limiting steps for ORR kinetics are determined to be the charge transfer reaction and oxygen adsorption/diffusion process on the electrode surface. This work highlights an effective way for developing the cathode candidates with high electrocatalytic activity and superior stability.     

PtFe alloy catalyst supported on porous carbon nanofiber with high activity and durability for oxygen reduction reaction

To reduce the high cost of oxygen reduction reaction (ORR) catalyst and improve the performance of the proton exchange membrane fuel cell (PEMFC), low-Pt or non-Pt catalysts have been studied in recent years. In this paper, PtFe alloy nanoparticles are loaded on porous carbon nanofiber (PCNF) via one-step modified glycol reduction method by adjusting solution pH. On the surface of PCNF, PtFe alloy nanoparticle can be uniformly dispersed with a narrow particle size distribution. The catalyst Pt_4.8Fe/PCNF prepared in pH = 7 solution with PCNF as carbon support exhibits better ORR performance, which shows even 18 mV higher onset potential than that of commercial catalyst Pt/C (Johnson Matthey, JM20). Moreover, comparable durability is also obtained through accelerated durability test (ADT) test after 2000 cycles. The excellent performance of Pt_4.8Fe/PCNF catalyst may attribute to the structural and electronic effects of transition metal in the PtFe alloy. The rough surface and porous structure of PCNF is also supposed to be beneficial for performance improvement.     

Pt overgrowth on carbon supported PdFe seeds in the preparation of core-shell electrocatalysts for the oxygen reduction reaction

In this study, a novel core-shell structured Pd₃Fe@Pt/C electrocatalyst, which is based on Pt deposited onto carbon supported Pd₃Fe nanoparticles, is prepared for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). The carbon supported Pd₃Fe nanoparticles act as seeds to guide the growth of Pt. The formation of the core-shell structured Pd₃Fe@Pt/C is confirmed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and electrochemical characterization. The higher surface area of the synthesized catalyst suggests that the utilization of Pt in the Pd₃Fe@Pt/C catalyst is higher than that in Pt/C. Furthermore, better electrocatalytic performance than that of Pt/C and Pd₃Fe/C catalyst is observed in the ORR which follows a four-electron path. Consequently, the results indicate that the Pd₃Fe@Pt/C catalyst could be used as a more economically viable alternative for the ORR of PEMFCs.