Direct ethanol fuel cells based on PtSn anodes: the effect of Sn content on the fuel cell performance

In the present work, several carbon supported PtSn catalysts with different Pt/Sn atomic ratios were synthesized and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Both the results of TEM and XRD showed that all in-house prepared carbon supported Pt and PtSn catalysts had nanosized particles with narrow size distribution. According to the primary analysis of XPS results, it was confirmed that the main part of Pt of the as-prepared catalysts is in metallic state while the main part of Sn is in oxidized state. The performances of single direct ethanol fuel cells were different from each other with different anode catalysts and at different temperatures. It was found that, the single DEFC employing Pt₃Sn₂/C showed better performance at 60 °C while the direct ethanol fuel cells with Pt₂Sn₁/C and Pt₃Sn₂/C exhibited similar performances at 75 °C. Furthermore, at 90 °C, Pt₂Sn₁/C was identified as a more suitable anode catalyst for direct ethanol fuel cells in terms of the fuel cell maximum power density. Surface oxygen-containing species, lattice parameters and ohmic effects, which are related to the Sn content, are thought as the main factors influencing the catalyst activity and consequently the performance of single direct ethanol fuel cells.     

Enhancement of the electrooxidation of ethanol on Pt–Sn–P/C catalysts prepared by chemical deposition process

In this paper, five Pt₃Sn₁/C catalysts have been prepared using three different methods. It was found that phosphorus deposited on the surface of carbon with Pt and Sn when sodium hypophosphite was used as reducing agent by optimization of synthetic conditions such as pH in the synthetic solution and temperature. The deposition of phosphorus should be effective on the size reduction and markedly reduces PtSn nanoparticle size, and raise electrochemical active surface (EAS) area of catalyst and improve the catalytic performance. TEM images show PtSnP nanoparticles are highly dispersed on the carbon surface with average diameters of 2 nm. The optimum composition is Pt₃Sn₁P₂/C (note PtSn/C-3) catalyst in my work. With this composition, it shows very high activity for the electrooxidation of ethanol and exhibit enhanced performance compared with other two Pt₃Sn₁/C catalysts that prepared using ethylene glycol reduction method (note PtSn/C-EG) and borohydride reduction method (note PtSn/-B). The maximum power densities of direct ethanol fuel cell (DEFC) were 61 mW cm⁻² that is 150 and 170% higher than that of the PtSn/C-EG and PtSn/C-B catalyst.     

PtM/C (M = Sn,Ru, Pd,W) based anode direct ethanol–PEMFCs: Structural characteristics and cell performance

In the present work, the role of the structural characteristics of Pt-based catalysts on the single direct ethanol proton exchange membrane fuel cell (PEMFC) performance is examined. Several PtM/C (M = Sn, Ru, Pd, W) catalysts were characterized by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD) and then evaluated as anode catalysts in single direct ethanol fuel cells. XRD spectra showed that Pt lattice parameter decreases with the addition of Ru or Pd and increases with the addition of Sn or W. According to the obtained experimental results, PtSn catalysts presented better electrocatalytic activity towards ethanol electro-oxidation. Based on these results, PtSn/C catalysts with different Pt/Sn atomic ratio were tested and compared. The maximum power density values obtained were correlated with the structural characteristics of the catalysts. A volcano type behaviour between the fuel cell maximum power density and the corresponding atomic percentage of Sn (Sn%) was observed. It was also observed that Sn% affects almost linearly the Pt_xSn_y catalysts’ lattice parameter.     

Controllable synthesis of efficient Ru-doped PtSn alloy nanoplate electrocatalysts for methanol oxidation reaction

Platinum (Pt) is considered as the preferred metal catalyst for methanol oxidation reactions. However, the application prospects of Pt catalysts are limited due to the inherent scarcity and cost. Enabling a trace amount of Pt to exert satisfactory catalytic activity and durability has become a key issue in designing electrocatalysts. Here, Ru-doped PtSn alloy nanoplates (PtSn@Ru NP) with an average particle size of less than 5 nm were controllably synthesized by adjusting the Pt–Sn atomic ratio. Compared with Ru-doped PtSn alloy nanospheres (PtSn@Ru NS/C, 714.7 mA/mg_Pt), PtSn bimetallic nanoplates (PtSn NP/C, 880.2 mA/mg_Pt) and commercial Pt/C (299.6 mA/mg_Pt), the prepared PtSn@Ru NP/C (1105.1 mA/mg_Pt) exhibited an extraordinary methanol oxidation mass activity. Furthermore, the peak oxidation current retention of PtSn@Ru NP/C was as high as at 87.5% after 1000 accelerated durability tests. The significantly enhanced catalytic performance and durability were attributed to the synergistic effect of the alloy components and morphological advantages. This work has led us to think more deeply about the constitutive relationship between structure and performance.     

Electrooxidation of CO and methanol on well-characterized carbon supported PtxSn electrodes. Effect of crystal structure

The role of two intermetallic phases of PtSn, namely Pt₃Sn (fcc phase) and PtSn (hcp phase) for the electrooxidation of CO and methanol has been evaluated. Carbon supported Pt₃Sn and PtSn nanosized particles have been prepared by controlled surface reactions. The actual structure of the PtSn alloys has been evaluated and confirmed by means of XRD and HR-TEM studies which reveal the predominance of either the hcp or the fcc phase in each catalyst. The catalysts have been further characterized to identify the actual metal loading and Pt/Sn atomic ratio in order to eliminate particle size or metal loading effects on their electrocatalytic performance. The performance of the catalysts for the electrooxidation of CO and methanol has been evaluated by electrochemical techniques along with in situ techniques such as electrochemical coupled Infrared Reflection Absorption Spectroscopy (EC-IRAS) and differential electrochemical mass spectrometry (DEMS). Altogether, the results presented in this work reveal that Pt₃Sn fcc is more active than PtSn hcp for the electrooxidation of CO and methanol and that the contribution of the hcp phase in those electrocatalytic processes is negligible.     

Carbon paper supported Pt/Au catalysts prepared via Cu underpotential deposition-redox replacement and investigation of their electrocatalytic activity for methanol oxidation and oxygen reduction reactions

Through a simple and rapid method, carbon papers (CPs) were coated with Au and the resulting Au/CP substrates were used for the preparation of Pt/Au/CP by Cu underpotential deposition (Cu UPD) and redox replacement technique. A series of Pt_n/Au/CP catalysts (where n = number of UPD-redox replacement cycles) were synthesized and their electrochemical properties for methanol oxidation reaction (MOR), and oxygen reduction reaction (ORR) were investigated by electrochemical measurements. The Pt_n/Au/CP electrodes show higher electrocatalytic activity and enhanced poison tolerance for the MOR as compared to a commercial Pt/C on CP (Pt/C/CP). The highest mass specific activity and Pt utilization efficiency for MOR was observed on Pt₁/Au/CP with a thickness close to a monatomic Pt layer. Chronoamperometric tests in methanol solution revealed that Pt_n/Au/CPs have much higher CO tolerance compared to Pt/C/CP. Among the Pt_n/Au/CPs, CO tolerance decreases with increasing the amount of deposited Pt, indicating that the exposed Au atoms in close proximity to Pt plays a positive role against CO poisoning. Compared with the Pt/C/CP, all the Pt_n/Au/CP electrodes show more positive onset potentials and lower overpotentials for ORR. For instance, the onset potential of ORR is 150 mV more positive and the overpotential is ∼140 mV lower on Pt₄/Au/CP with respect to Pt/C/CP.     

Tuning concave PtSn nanocubes for efficient ethylene glycol and glycerol electrocatalysis

Shape-controlled synthesis of well-defined nanostructures offers a great opportunity to promote electrocatalytic performances while reducing the mass loading of noble metals. Herein, we show how morphology can effectively affect the electrocatalytic properties of nanocrystals for alcohol electrooxidation reaction, a key barrier to the application of fuel cells. We report the synthesis of a new generation of alloyed PtSn concave nanocubes (CNCs) through a facile one-pot wet-chemical method. Owing to strong synergistic effect between Pt and Sn, modified electronic structure, as well as high surface areas, the as-obtained alloyed PtSn CNCs can display outstanding electrocatalytic performances for liquid fuel electrooxidation. Impressively, the optimized Pt₄Sn₁ concave nanocubes (CNCs) can achieve a factor of 5.1 enhancements in mass activity and a factor of 5.9 enhancements in specific activity towards ethylene glycol oxidation (EGOR) in comparison with commercial Pt/C catalysts. Moreover, 4.6 and 5.3-fold enhancements in mass and specific activity were also acquired for glycerol oxidation reaction (GOR) compared to those of the commercial Pt/C, holding great promise for future application in fuel cells.     

Study of ethanol electro-oxidation in acid environment on Pt3Sn/C anode catalysts prepared by a modified polymeric precursor method under controlled synthesis conditions

A carbon-supported binary Pt₃Sn catalyst has been prepared using a modified polymeric precursor method under controlled synthesis conditions. This material was characterized using X-ray diffraction (XRD), and the results indicate that 23% (of a possible 25%) of Sn is alloyed with Pt, forming a dominant Pt₃Sn phase. Transmission electron microscopy (TEM) shows good dispersion of the electrocatalyst and small particle sizes (3.6 nm ± 1 nm). The polarization curves for a direct ethanol fuel cell using Pt₃Sn/C as the anode demonstrated improved performance compared to that of a PtSn/C E-TEK, especially in the intrinsic resistance-controlled and mass transfer regions. This behavior is probably associated with the Pt₃Sn phase. The maximum power density for the Pt₃Sn/C electrocatalyst (58 mW cm⁻²) is nearly twice that of a PtSn/C E-TEK electrocatalyst (33 mW cm⁻²). This behavior is attributed to the presence of a mixed Pt₉Sn and Pt₃Sn alloy phase in the commercial catalysts.     

Direct Ethanol Fuel Cells: The influence of structural and electronic effects on Pt–Sn/C electrocatalysts

Carbon-supported platinum-tin electrocatalysts (Pt–Sn/C) are known to be the most efficient fuel cell anode material to oxidize ethanol in the so-called Direct Ethanol Fuel Cells (DEFC). However, the platinum-tin binary system presents distinct phases depending on the amount of Sn (i.e., the Pt:Sn ratio) and on the thermal annealing temperatures, as well as the presence of oxides (e.g. SnO₂) whose influence on the performance of DEFCs is not well understood. In this work, Pt–Sn catalysts presenting distinct Pt:Sn ratios were prepared, characterized and tested in a single DEFC. The combined results from DEFC tests and structural characterization techniques showed that increasing the amount of Sn dissolved into the Pt structure enhances DEFC performance but also that Sn content alone does not explain the overall behavior. Microstructural effects on the DEFC response was further investigated by performing a comprehensive study using high intensity X-ray Diffraction and in situ–X-Ray Absorption Spectroscopy provided by synchrotron light on Pt₃Sn₁/C samples subjected to thermal treatments in a reducing H₂ atmosphere at temperatures of 100, 200, 300, 400, and 500 °C. The results showed that best DEFC performance depends on a balance between the amount of Sn dissolved in Pt, the formation of a new phase (PtSn) and also on the presence of tin oxides, yielding a material with an optimized modified 5d-band electronic structure, which was obtained with a thermal treatment at 200 °C.     

Highly active and durable carbon support Pt-rare earth catalyst for proton exchange membrane fuel cell

Pt-rare earth catalysts are highly efficient novel electrocatalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) due to their high stability and activity. In this study, we prepare Pt-YO_x/C catalysts using the traditional wet chemical reduction method. The optimal quantity of Y-oxides loaded onto the Pt/C surface is determined based on electrochemical performance using linear sweep voltammetry (LSV) and cyclic voltammetry (CV) methods. After accelerated durability tests (ADT), the remnant electrochemical surface area (ECSA) and mass active (MA) in Pt-YO_x/C catalyst are relatively higher compared to the commercial Pt/C (JM). In the single-cell test, the maximum mass power densities of the MEAs prepared by self-made Pt-YO_x/C and Pt/C (JM) catalysts in cathodes record at 1895 and 1371 mW mg_Pt⁻¹, respectively, which shows a successful increment in platinum utilization. These results indicate that Pt-YO_x/C catalyst can potentially improve the durability and lower the cost of PEMFCs.     

Nanocomposite of platinum and prussian blue: A highly active and stable electrocatalyst towards oxygen reduction reaction in acidic media

Deployment of proton exchange membrane fuel cells (PEMFCs) are of vital importance for the mitigation of fossil energy shortage and environment pollution. A significant amount of Pt on cathode is highly needed to accelerate the process of sluggish oxygen reduction reaction (ORR) and maintains a stable long-term performance. During ORR, the yield of undesirable hydrogen peroxide through a two-electron pathway not only decreases outer power but also weakens the long-term stability. Herein, Pt-prussian blue (PB) composite, featuring around structure, is firstly proposed and facilely fabricated via electrostatic self-assembly strategy. Pt₁PB_0.25/C shows 50% higher activity than commercial Pt/C, rationally ascribed to modulated electronic structure and higher selectivity towards four-electron pathway. Moreover, in contrast with the striking 38% loss in mass activity for Pt/C after accelerated degradation tests (ADTs), Pt₁PB_0.25/C shows only a 15% decrease possibly due to the elimination of hydrogen oxide and the anchor interaction between Pt and PB. The employment of PB with a synergy role paves an efficient way for the fabrication of brand-new Pt-based catalysts with high activity and stability.     

ZrO2 anchored core-shell Pt–Co alloy particles through direct pyrolysis of mixed Pt–Co–Zr salts for improving activity and durability in proton exchange membrane fuel cells

Highly active and durable Pt-based catalysts for oxygen reduction reaction (ORR) are very important and necessary for the proton exchange membrane fuel cells (PEMFCs). In this paper, we report the preparation and performance study of ORR catalysts composed of core-shell Pt–Co alloy nanoparticles (NPs) on multi-walled carbon nanotubes (MWCNTs) anchored with ZrO₂ NPs (denoted as Pt–Co–ZrO₂/MWCNTs). Thanks to the unique three-phase structure, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR at 0.9 V versus reversible hydrogen electrode (RHE) is1577 mA mg_Pt^?1, which is ～6.6-fold higher than that of the commercial Pt/C (238 mA mg_Pt^?1). After 50,000 cycles for durability test, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR remained 88% of its initial value. In stark contrast, that of Pt/C kept only about 56.3% of its initial value. More importantly, its catalytic performance was fully observed/verified in a H₂-air PEMFC single cell test. When the Pt loading of Pt–Co–ZrO₂/MWCNTs loaded cathode was one fourth of that with commercial Pt/C as the cathode catalyst, comparable cell performance was achieved. More impressively, the MEA with Pt–Co–ZrO₂/MWCNTs underwent only 24.5% degradation in maximum power density after 30,000 accelerated durability tests (ADTs). However, the MEA with Pt/C after 30,000 ADTs exhibited 39.6% performance loss in maximum power density. The enhanced mass activity and catalytic durability of Pt–Co–ZrO₂/MWCNTs could be attributed to the core-shell Pt–Co alloy NPs with Pt-rich surface and the interface effect between Pt–Co alloy NPs and oxygen vacancy-rich ZrO₂ NPs. In addition, this research also provided a solution to the durability issue of cathodes without sacrificing ORR mass activity, which would promote practical application of PEMFCs.     

Theoretical research on the H2 generation mechanism on Pt6, Pt5Sn5 and Pt3Sn6 clusters by density functional theory

In this paper, the mechanisms of H₂ evolution on Pt₆, Pt₅Sn₅, and Pt₃Sn₆ clusters were respectively investigated by the B3LYP method of density functional theory (DFT). The B3LYP functional with non-local dispersion corrections (B3LYP-D3) method were performed to investigate the adsorption of H and H⁺ on clusters. The calculation results indicated that the adsorption energy of H on Pt reduced due to the interaction of Sn and Pt, which promoted H desorption from Pt to form H₂. Meanwhile, Sn atom of Pt₅Sn₅ and Pt₃Sn₆ clusters had strong interaction with H⁺ due to the existence of Pt, which was benefit for the reduction of H⁺ on Sn atom. As a consequence, Pt₅Sn₅ and Pt₃Sn₆ showed lower potential barrier and higher activities than Pt for H₂ evolution. The potential barriers of H₂ formation over Pt₃Sn₆ clusters was only 11.1% of that over Pt cluster.     

Highly efficient electrocatalysts for oxygen reduction reaction: Nitrogen-doped PtNiMo ternary alloys

The relatively low efficiency of the reaction of oxygen reduction (ORR) remains among the main obstacles for hydrogen fed proton exchange membrane fuel cells (H-PEMFCs) commercialization.In the present work, PtNiMo ternary alloy catalysts are obtained through reducing by NaBH₄ and subsequent thermal annealing in NH₃ at 1.0 atm. The as prepared catalysts are physico-chemically (XRD, TEM and XPS) characterized, exhibiting alloy nanostructure.From the electrochemical tests it is found that they exhibit high ORR activity in aqueous solutions saturated with O₂ and acidified with HClO₄. From the as synthesized catalysts, Pt₃Ni₃MoN/C shows the highest mass activity (539.41 mA mg⁻¹ Pt); 3.5 times greater than that observed over commercial Pt/C (154.46 mA mg⁻¹ Pt). Moreover, they show very good stability, while their ORR activity is only slightly altered after 5,000 cycles.These highly performing and low cost catalysts could thus open up new possibilities for the commercialization of hydrogen fed PEMFCs.     

Carbon supported Pt-Y electrocatalysts for the oxygen reduction reaction

Carbon supported Pt₃Y (Pt₃Y/C) and PtY (PtY/C) were investigated as oxygen reduction reaction (ORR) catalysts. After synthesis via reduction by NaBH₄, the alloy catalysts exhibited 10-20% higher mass activity (mA mg_Pt⁻¹) than comparably synthesized Pt/C catalyst. The specific activity (μA cm_Pt⁻²) was 23 and 65% higher for the Pt₃Y/C and PtY/C catalysts, respectively, compared to Pt/C. After annealing at 900 °C under a reducing atmosphere, Pt₃Y/C-900 and PtY/C-900 catalysts showed improved ORR activity; the Pt/C and Pt/C-900 (Pt/C catalyst annealed at 900 °C) catalysts exhibited specific activities of 334 and 393 μA cm_Pt⁻², respectively, while those of the Pt₃Y/C-900 and PtY/C-900 catalysts were 492 and 1050 μA cm_Pt⁻², respectively. X-ray diffraction results revealed that both the Pt₃Y/C and PtY/C catalysts have a fcc Pt structure with slight Y doping. After annealing, XRD showed that more Y was incorporated into the Pt structure in the Pt₃Y/C-900 catalyst, while the PtY/C-900 catalyst remained unchanged. Although these results suggested that the high ORR activity of the PtY/C-900 catalyst did not originate from Pt-Y alloy formation, it is clear that the Pt-Y system is a promising ORR catalyst which merits further investigation.     

One-pot synthesis of Pt/CeO2/C catalyst for improving the ORR activity and durability of PEMFC

Oxygen reduction reaction (ORR) activity and durability of Pt catalysts should be both valued for successful commercialization of proton exchange membrane fuel cells (PEMFCs). We offer a facile one-pot synthesis method to prepare Pt/CeO₂/C composite catalysts. CeO₂ nanoparticles, with high Ce³⁺ concentration ranging from 30.9% to 50.6%, offers the very defective surface where Pt nanoparticles preferentially nuclear and growth. The Pt nanoparticles are observed sitting on the CeO₂ surface, increasing the PtCeO₂ interface. The high concentration of oxygen vacancies on CeO₂ surface and large PtCeO₂ interface lead to the strong PtCeO₂ interaction, effectively improving the ORR activity and durability. The mass activity is increased by up to 50%, from 36.44 mA mg^?1 of Pt/C to 52.09 mA mg^?1 of Pt/CeO₂/C containing 20 wt.% CeO₂. Pt/CeO₂/C composite catalysts containing 10–30 wt.% CeO₂ loss about 80% electrochemical surface area after 10,000 cycles, which is a fivefold enhancement in durability, compared to Pt/C losing 79% electrochemical surface area after 2000 cycles.     

Acid-treated PtSn/C and PtSnCu/C electrocatalysts for ethanol electro-oxidation

PtSn/C with Pt:Sn atomic ratio of 50:50 and PtSnCu/C electrocatalysts with different Pt:Sn:Cu atomic ratios were prepared using NaBH₄ as reducing agent and carbon black Vulcan XC72 as support. In a second step, the electrocatalysts were treated with nitric acid to remove the less noble metals (chemical dealloying). The obtained materials were characterized by X-ray diffraction, EDX analysis, TEM images with EDX scan-line and cyclic voltammetry. The electro-oxidation of ethanol was studied by chronoamperometry and on single direct ethanol fuel cell (DEFC). The X-ray diffractograms of the as-synthesized electrocatalysts showed the typical face-centered cubic (FCC) structure of Pt alloys. After acid treatment the FCC structure was maintained and Sn and Cu atoms were removed from the nanoparticles surface. Chronoamperometry measurements showed a strong increase of performance of PtSn/C and PtSnCu/C electrocatalysts after acid treatment; however, under DEFC conditions at 100 °C, only acid-treated PtSn/C electrocatalyst showed superior performance compared to commercial PtSn/C from BASF.     

Understanding the electrocatalytic activity of PtxSny in direct ethanol fuel cells

In the present work, the activity of Pt_xSn_y/C catalysts towards ethanol, acetaldehyde and acetic acid electrooxidation reactions is investigated for each one separately by means of cyclic voltammetry. To this purpose, a series of Pt_xSn_y/C catalysts with different atomic ratio (x:y = 2:1, 3:2, 1:1) and small particle size (∼3 nm) are fast synthesized by using the pulse microwave assisted polyol method. The catalysts are well dispersed over the carbon support based on the physicochemical characterization by means of XRD and TEM. Concerning the ethanol electrooxidation, it is found that the Sn addition strongly enhances Pt's electrocatalytic activity and the contributing effect of Sn depends on: (i) the Sn content and (ii) the operating temperature. More precisely, at lower temperatures, Sn-rich catalysts exhibit better ethanol electrooxidation performance while at higher temperatures Sn-poor catalysts give better performance. In the case of acetaldehyde electrooxidation, Pt₁Sn₁/C catalyst exhibits the highest activity at all the investigated temperatures; due to the role of Sn, which could effectively remove C₂ species and inhibit the poison formation by supplying oxygen-containing species. Finally, it is found that the Pt_xSn_y/C catalysts are almost inactive (little current was measured) towards the acetic acid electrooxidation. The above findings indicate that Sn cannot substantially promote the electrooxidation of acetic acid to C₁ species.     

Lattice-strained Pt nanoparticles anchored on petroleum vacuum residue derived N-doped porous carbon as highly active and durable cathode catalysts for PEMFCs

High cost and poor durability of Pt-based cathode catalysts for oxygen reduction reaction (ORR) severely hamper the popularization of proton exchange membrane fuel cells (PEMFCs). Tailoring carbon support is one of effective strategies for improving the performance of Pt-based catalysts. Herein, petroleum vacuum residue was used as carbon source, and nitrogen-doped porous carbon (N-PPC) was synthesized using a simple template-assisted and secondary calcination method. Small Pt nanoparticles (Pt NPs) with an average particles size of 1.8 nm were in-situ prepared and spread evenly on the N-PPC. Interestingly, the lattice compression (1.08%) of Pt NPs on the N-PPC (Pt/N-PPC) was clearly observed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), which was also verified by the shift of (111) crystal plane of Pt on N-PPC to higher angles. The X-ray photoelectron spectroscopy (XPS) results suggest that the N-PPC support had a strong effect on anchoring Pt NPs and endowing surface Pt NPs with lowered d band center. Thus, the Pt/N-PPC as a catalyst simultaneously boosted the ORR activity and durability. The specific activity (SA) and mass activity (MA) of the Pt/N-PPC at 0.9 V reached 0.83 mA cm⁻² and 0.37 A mg_Pt⁻¹, respectively, much higher than those of the commercial Pt/C (0.21 mA cm⁻² and 0.11 A mg_Pt⁻¹) in 0.1 M HClO₄. The half-wave potential (E_1/2) of Pt/N-PPC exhibited only a minimal negative shift of 7 mV after 30,000 accelerated durability tests (ADT) cycles. More importantly, an H₂–O₂ fuel cell with a Pt/N-PPC cathode achieved a power density of 866 mW cm⁻², demonstrating that the prepared catalyst has a promising application potential in working environment of PEMFCs.     

Effect of Pt–Pd/C coupled catalyst loading and polybenzimidazole ionomer binder on oxygen reduction reaction in high-temperature PEMFC

Polybenzimidazole (PBI) was studied as an ionomer binder at varying ratios (1–7) in a 20–40 wt% Pt–Pd/C cathode-coupled catalyst layer for the oxygen reduction reaction (ORR) in a high-temperature proton exchange membrane fuel cell (HT-PEMFC). Catalytic activity was examined by CV and LSV, while the properties of the catalysts were characterized by FESEM-EDX, N₂ adsorption–desorption, XRD and FTIR. The results showed that the distribution of metals on the carbon surface, carbon wall thickness and the interaction between ionomer and coupled catalysts affected the ORR performance. The fabricated membrane electrode assembly with 5:95 PBI: 30 wt% Pt–Pd/C catalyst ratio exhibited the best performance and highest durability for HT-PEMFC at 170 °C, yielding a power density of 1.30 Wcm⁻² with 0.02 mg_Pt/cm Pt loading. This performance of ultra-low metal loading of coupled Pt–Pd/C electrocatalyst with PBI binder was comparable to those reported by other studies, highlighting a promising catalyst for fuel cell application.