One-step synthesis of carbon-supported Pd–Pt alloy electrocatalysts for methanol tolerant oxygen reduction

A facile, one-step reduction route was developed to synthesize Pd-rich carbon-supported Pd–Pt alloy electrocatalysts of different Pd/Pt atomic ratios. As-prepared Pd–Pt/C catalysts exhibit a single phase fcc structure and an expansion lattice parameter. Comparison of the oxygen reduction reaction (ORR) on the Pd–Pt/C alloy catalysts indicates that the Pd₃Pt₁/C bimetallic catalyst exhibits the highest ORR activity among all the Pd–Pt alloy catalysts and shows a comparative ORR activity with the commercial Pt/C catalyst. Moreover, all the Pd–Pt alloy catalysts exhibited much higher methanol tolerance during the ORR than the commercial Pt/C catalyst. High methanol tolerance of the Pd–Pt alloy catalysts could be attributed to the weak adsorption of methanol induced by the composition effect, to the presence of Pd atoms and to the formation of Pd-based alloys.     

One-pot fabrication of single-crystalline octahedral Pd-Pt nanocrystals with enhanced electrocatalytic activity for methanol oxidation

This study reports the synthesis of octahedral Pd-Pt bimetallic alloy nanocrystals through a facile, one-pot, templateless, and seedless hydrothermal method in the presence of glucose and hexadecyl trimethyl ammonium bromide. The morphologies, compositions, and structures of the Pd-Pt nanocrystals were fully characterized by various physical techniques, thereby demonstrating their highly alloying octahedral nanostructures. The formation or growth mechanism of the Pd-Pt bimetallic alloy nanocrystals was explored and is discussed here based on the experimental observations. In addition, the synthesized Pd-Pt nanocrystals were applied to the methanol oxidation reaction (MOR) in alkaline media, which proved that the as-prepared catalysts exhibit enhanced electrocatalytic activity for MOR. Pd₁Pt₃ exhibited the best stability and durability, and its mass activity was 3.4 and 5.2 times greater than those of Pt black and Pd black catalysts, respectively. The facile synthetic process and excellent catalytic performance of the as-prepared catalysts demonstrate that they have the potential to be used in direct methanol fuel cell techniques.     

Bimetallic Cluster Provides a Higher Activity Electrocatalyst for Methanol Oxidation

The cluster complex Pt₂Ru₄(CO)₁₈ was used as a precursor to prepare a 60 wt% 1:2 Pt:Ru nanoparticles on carbon (PtRu/C) for use as an electrocatalyst for methanol oxidation. This bimetallic carbonyl cluster complex was found to provide smaller, more uniform bimetallic nanoparticle that exhibited higher electrocatalytic activity than a 60 wt% 1:1 Pt:Ru commercial catalyst from E-Tek. Using bimetallic cluster precursors simplifies the synthetic procedures by reducing the need for high temperature reduction and assures a more intimate mixing of the two different metals. Transmission electron microscopy (TEM) images of the catalyst obtained from the cluster precursor showed bimetallic nanoparticles having a narrow size range of 2–3 nm that were dispersed uniformly over the surface of the support. Images of the commercial catalyst showed particles 3–4 nm in diameter that tended to agglomerate near the edges of the carbon support particles. Cyclic voltammograms of methanol oxidation from the two catalysts showed significantly higher activity for the cluster-derived catalyst. The onset potential for methanol oxidation for the cluster-derived catalyst was approximately 170 mV lower than that of the commercial catalyst at 100 A/g Pt, and approximately 250 mV lower at 400 A/g Pt. ^* This report is dedicated to Prof. Günter Schmid on the occasion of his 70th birthday.     

萘在贵金属Pd、Pt及Pd-Pt催化剂上的加氢活性及耐硫性能

采用等体积浸渍法制备了SiO2-Al2O3负载的Pd、Pt单金属催化剂及Pd/Pt摩尔比分别为1∶1、1∶4、4∶1的双金属催化剂(Pd1Pt1、Pd1Pt4、Pd4Pt1),对其进行X射线衍射(XRD)、透射电镜(TEM)、CO化学吸附和X射线光电子能谱(XPS)表征,并详细考察了各催化剂的萘加氢活性和耐硫性能.结果表明,在实验考察范围内,Pd4Pt1催化剂上的萘转化率最高可达98.2%,全饱和产物十氢萘选择性最高可达93.6%,十氢萘反/顺生成率之比最高可达7.8,均高于单金属Pd(97.5%,59.1%,4.3)和Pt(96.8%,39.9%,2.9)催化剂的值.萘在三种催化剂上的加氢速率顺序为vPd4Pt1vPdvPt.添加二苯并噻吩(DBT)后Pd4Pt1上的萘转化率和十氢萘选择性仍然最高,十氢萘反/顺比在Pt催化剂上不受影响,在Pd4Pt1催化剂上稍有降低,而在Pd催化剂上降低明显.在三种不同Pd/Pt摩尔比的双金属催化剂中,Pd4Pt1催化剂上的萘转化率和十氢萘选择性在添加DBT前后都是最佳的.     

Supported Pd–Cu Bimetallic Nanoparticles That Have High Activity for the Electrochemical Oxidation of Methanol

Monodisperse bimetallic Pd–Cu nanoparticles with controllable size and composition were synthesized by a one‐step multiphase ethylene glycol (EG) method. Adjusting the stoichiometric ratio of the Pd and Cu precursors afforded nanoparticles with different compositions, such as Pd₈₅–Cu₁₅, Pd₅₆–Cu₄₄, and Pd₃₉–Cu₆₁. The nanoparticles were separated from the solution mixture by extraction with non‐polar solvents, such as n‐hexane. Monodisperse bimetallic Pd–Cu nanoparticles with narrow size‐distribution were obtained without the need for a size‐selection process. Capping ligands that were bound to the surface of the particles were removed through heat treatment when the as‐prepared nanoparticles were loaded onto a Vulcan XC‐72 carbon support. Supported bimetallic Pd–Cu nanoparticles showed enhanced electrocatalytic activity towards methanol oxidation compared with supported Pd nanoparticles that were fabricated according to the same EG method. For a bimetallic Pd–Cu catalyst that contained 15 % Cu, the activity was even comparable to the state‐of‐the‐art commercially available Pt/C catalysts. A STEM‐HAADF study indicated that the formation of random solid‐solution alloy structures in the bimetallic Pd₈₅–Cu₁₅/C catalysts played a key role in improving the electrochemical activity.     

High-loading Pt nanoparticles on mesoporous carbon with large mesopores for highly active methanol electro-oxidation

High metal-loading Pt/C electrocatalysts are important for the fabrication of thin-layered membrane electrode assemblies (MEAs). However, the preparation of high-loading Pt catalysts with a narrow size distribution of nanoparticles remains a challenge. Herein, ordered mesoporous carbon (OMC) with large mesopores (~15 nm) and a high surface area (1316.0 m² g^?1) was fabricated using a SiO₂ nanosphere array as a template. This material was developed to support a high loading of Pt nanoparticles (60 wt%) and was then used as an electrocatalyst for the methanol oxidation reaction (MOR). The prepared Pt/OMC contains Pt nanoparticles with an average size of ~1.9 nm that are uniformly dispersed on the mesoporous walls of the OMC. The Pt/OMC catalyst exhibits smaller Pt nanoparticle size, greater Pt dispersion, larger specific electrochemically active surface area (ECSA), and higher electrocatalytic activity for the MOR than the carbon black (Vulcan XC-72R)-supported Pt and the commercial Pt/C catalysts.     

Size‐Controllable Synthesis of Trimetallic RhPdPt Island‐Shaped Nanoalloys with Enhanced Electrocatalytic Performance for Ethanol Oxidation in Alkaline Medium

Size‐controllable, high‐yield, island‐shaped RhPdPt trimetallic nanocrystals with sub‐2.0 nm islands have been successfully synthesized through a facile aqueous solution approach. The results of X‐ray diffraction (XRD), energy‐dispersive X‐ray (EDX) line scanning and elemental mapping analysis showed the as‐synthesized RhPdPt nanocrystals are alloy structures. These island‐shaped RhPdPt trimetallic nanoalloys showed a composition‐dependent electrocatalytic performance for ethanol oxidation in alkaline medium. Due to the special structure and intermetallic synergies, the Rh₁₀Pd₄₀Pt₅₀ nanoalloys exhibited an enhanced catalytic activity and durability relative to island‐shaped Pd₅₀Pt₅₀ bimetallic nanoalloys and commercial Pt black. The peak current density for Rh₁₀Pd₄₀Pt₅₀ nanoalloys was 1.81 and 1.38 times that for commercial Pt black and Pd₅₀Pt₅₀ nanoalloys, respectively. In addition, the peak potential on Rh₁₀Pd₄₀Pt₅₀ nanoalloys decreased 42 mV relative to commercial Pt black and Pd₅₀Pt₅₀ nanoalloys.     

Revealing the Effect of Surface Composition on Multiwalled Carbon Nanotubes Supported Pt-Fe Alloy Electrocatalysts for Methanol Oxidation Performance

The designs of efficient and inexpensive Pt-based catalysts for methanol oxidation reaction (MOR) are essential to boost the commercialization of direct methanol fuel cells. Here, the highly catalytic performance PtFe alloys supported on multiwalled carbon nanotubes (MWCNTs) decorating nitrogen-doped carbon (NC) have been successfully prepared via co-engineering of the surface composition and electronic structure. The Pt₁Fe₃@NC/MWCNTs catalyst with moderate Fe³⁺ feeding content (0.86 mA/mg_Pt) exhibits 2.26-fold enhancement in MOR mass activity compared to pristine Pt/C catalyst (0.38 mA/mg_Pt). Furthermore, the CO oxidation initial potential of Pt₁Fe₃@NC/MWCNTs catalyst is lower relative to Pt/C catalyst (0.71 V and 0.80 V). Benefited from the optimal surface compositions, the anti-corrosion ability of MWCNT, strong electron interaction between PtFe alloys and MWCNTs and the N-doped carbon (NC) layer, the Pt₁Fe₃@NC/MWCNTs catalyst presents an improved MOR performance and anti-CO poisoning ability. This study would open up new perspective for designing efficient electrocatalysts for the DMFCs field.     

Promotional effect of Snad on the ethanol oxidation at Pt3Sn/C catalyst

Oxidation of ethanol was studied at Sn_ad modified and unmodified Pt₃Sn/C and Pt/C catalysts. Pt₃Sn/C and Pt/C catalysts were characterized by XRD. Potentiodynamic and chronoamperometric measurements were used to establish catalytic activity and stability. High activity achieved at Sn_ad modified Pt₃Sn/C catalyst has not been observed at any bimetallic catalyst so far. Promotional effect of Sn_ad on the ethanol oxidation was related to the enhancement of CO oxidation rate in bifunctional mechanism. It was shown that electrodeposited Sn exhibited different effect on the catalytic activity compared to Sn in alloy.     

Bimetallic Cu–Pt/nanoporous carbon composite as an efficient catalyst for methanol oxidation

A novel bimetallic Cu–Pt nanoparticle supported onto Cu/indirectly carbonized nanoporous carbon composite (Cu–Pt/ICNPCC) was prepared through a two-step process: first, carbonization of furfuryl alcohol-infiltrated MOF-199 [metal–organic framework Cu₃(BTC)₂ (BTC?=?1,3,5-benzene tricarboxylate)], without removing the Cu metal with HF aqueous solution; second, the partial galvanic replacement reaction (GRR) of Cu nanoparticles by Pt^IV upon immersion in a platinum(IV) chloride solution. The synthesized materials characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and electrochemical methods. The EDS result revealed that part of Cu nanoparticles have been substituted by Pt nanoparticles after GRR. The methanol oxidation at the surface of Cu–Pt/ICNPCC was investigated by cyclic voltammetry method in 0.5 M H₂SO₄ and indicated good electro-catalytic activity towards methanol oxidation (E_p?=?0.85 V vs. NHE and j_f?=?1.00 mA cm^?2). It is suggested that this improvement is attributed to the effect of proper Cu/ICNPCC for fine dispersion, efficient adhesion, and prevention of Pt coalescing.     

Nonenzymatic sensing of glucose at neutral pH values using a glassy carbon electrode modified with graphene nanosheets and Pt-Pd bimetallic nanocubes

We report on a nonenzymatic method for the determination of glucose using an electrode covered with graphene nanosheets (GNs) modified with Pt-Pd nanocubes (PtPdNCs). The latter were prepared on GNs by using N,N-dimethylformamide as a bifunctional solvent for the reduction of both metallic precursors and graphene oxide, and for confining the growth of PtPdNCs on the surface. The modified electrode displays strong and sensitive current response to the electrooxidation of glucose, notably at pH 7. The sensitivities increase in the order of Pt₁Pd₅NCs< Pt₁Pd₃NCs< Pt₅Pd₁NCs< Pt₃Pd₁NCs< Pt₁Pd₁NCs. At an applied potential of +0.25 V, the electrode responds linearly (R?=?0.9987) to glucose in up to 24.5 mM concentration, with a sensitivity of 1.4 μA cm^?2 M^?1. The sensor is not poisoned by chloride, and not interfered by ascorbic acid, uric acid and p-acetamidophenol under normal physiological conditions. The modified electrode also displays a wide linear range, good stability and fast amperometric response, thereby indicating the potential of the bimetallic materials for nonenzymatic sensing of glucose.

Structural and Electronic Effects of Carbon‐Supported PtxPd1−x Nanoparticles on the Electrocatalytic Activity of the Oxygen‐Reduction Reaction and on Methanol Tolerance

We report a systematic investigation on the structural and electronic effects of carbon‐supported Pt_xPd_1?x bimetallic nanoparticles on the oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) in acid electrolyte. Pt_xPd_1?x/C nanocatalysts with various Pt/Pd atomic ratios (x=0.25, 0.5, and 0.75) were synthesized by using a borohydride‐reduction method. Rotating‐disk electrode measurements revealed that the Pt₃Pd₁/C nanocatalyst has a synergistic effect on the ORR, showing 50 % enhancement, and an antagonistic effect on the MOR, showing 90 % reduction, relative to JM 20 Pt/C on a mass basis. The extent of alloying and Pt d‐band vacancies of the Pt_xPd_1?x/C nanocatalysts were explored by extended X‐ray absorption fine‐structure spectroscopy (EXAFS) and X‐ray absorption near‐edge structure spectroscopy (XANES). The structure–activity relationship indicates that ORR activity and methanol tolerance of the nanocatalysts strongly depend on their extent of alloying and d‐band vacancies. The optimal composition for enhanced ORR activity is Pt₃Pd₁/C, with high extent of alloying and low Pt d‐band vacancies, owing to favorable O? O scission and inhibited formation of oxygenated intermediates. MOR activity also shows structure dependence. For example, Pt₁Pd₃/C with Pt_rich?corePd_rich?shell structure possesses lower MOR activity than the Pt₃Pd₁/C nanocatalyst with random alloy structure. Herein, extent of alloying and d‐band vacancies reveal new insights into the synergistic and antagonistic effects of the Pt_xPd_1?x/C nanocatalysts on surface reactivity.     

Enhanced electro-oxidation of formic acid by a PdPt bimetallic catalyst on a CeO2-modified carbon support

PdPt bimetallic catalysts that employ CeO2-modified carbon black as a support have been prepared using an organic colloidal method.PdPt/CeO2-C shows excellent performance toward the anodic oxidation of formic acid.The effects of varying both Pd to Pt ratio and CeO2 content have been investigated.The optimal Pd to Pt atomic ratio is 15,indicating that addition of small amounts of Pt can significantly enhance the activity of the catalyst.When the CeO2 content in the catalyst reaches as high as ～15 wt.%,the catalyst shows the maximum activity.Adding CeO2 not only enhances the catalytic activity of the material,but may also change the mechanism of its catalysis of the anodic oxidation of formic acid.Pd15Pt1/15CeO2-C exhibited 60% higher activity than Pd/C,and had a negative shift in onset potential of more than 0.1 V.Based on characterization by X-ray diffraction,X-ray photoelectron spectroscopy,thermogravimetric analysis and transmission electron microscopy,the interactions between the components are revealed and discussed in detail.     

One-step synthesis of porous PtNiCu trimetallic nanoalloy with enhanced electrocatalytic performance toward methanol oxidation

Pt-based alloy nanoporous structures have attracted a lot of attention because of their high activity and stability toward alcohol oxidation reactions. Especially, Pt alloying with Earth-abundant metal can lower the cost of catalyst. Here, we introduce a one-pot approach to synthesize bimetallic PtCu and Ni-doped PtCu nanoalloy with porous structure. The as-synthesized Ni-doped Pt₆₀Ni₃Cu₃₇ nanoalloys exhibit excellent electrocatalytic properties toward methanol oxidation in acidic medium. The mass activity of the as-synthesized Pt₆₀Ni₃Cu₃₇ nanoalloys is 3.6 times and 5.3 times that of Pt₅₅Cu₄₅ nanoalloys and commercial Pt black for methanol oxidation in 0.2?M methanol solution. Besides, the stability of the as-synthesized Pt₆₀Ni₃Cu₃₇ nanoalloys was much better than Pt₅₅Cu₄₅ nanoalloys and commercial Pt black. After 3600?s chronoamperometry test, the remaining values of the Pt₆₀Ni₃Cu₃₇ nanoalloys are 3.7 times and 11.0 times that of Pt₅₅Cu₄₅ nanoalloys and commercial Pt black. And it is the first time to report that small amount of Ni dopants can boost the activity and stability of PtNiCu alloys toward methanol oxidation.     

Enhanced activity in ethanol oxidation of Pt<Subscript>3</Subscript>Sn electrocatalysts synthesized by microwave irradiation

High surface area carbon supported Pt and Pt₃Sn catalysts were synthesized by microwave irradiation and investigated in the ethanol electro-oxidation reaction. The catalysts were obtained using a modified polyol method in an ethylene glycol solution and were characterized in terms of structure, morphology and composition by employing XRD, STM and EDX techniques. The diffraction peaks of Pt₃Sn/C catalyst in XRD patterns are shifted to lower 2θ values with respect to the corresponding peaks at Pt/C catalyst as a consequence of alloy formation between Pt and Sn. Particle size analysis from STM and XRD shows that Pt and Pt₃Sn clusters are of a small diameter (∼2 nm) with a narrow size distribution. Pt₃Sn/C catalyst is highly active in ethanol oxidation with the onset potential shifted for ∼150 mV to more negative values and with ∼2 times higher currents in comparison to Pt/C.     

Catalytic oxidation of volatile organic compounds (VOCs). Oxidation of o-xylene over Pd and Pt/HFAU catalysts

The transformation of o-xylene in low concentration (1 700 ppmv) into air was investigated over Pd and Pt/HFAU catalysts (framework Si/Al ratio equal to 17 and 100). Whatever the catalyst, o-xylene oxidation into CO₂ and H₂O is accompanied by the retention within the zeolite pores of heavy compounds (‘coke’). The relative significance of these reactions depends on the operating conditions (temperature, time-on-stream) and on the catalyst characteristics (Pd or Pt, Si/Al ratio). Over Pt and Pd/HFAU(17), time-on-stream has a positive effect on the xylene oxidation apparently related to the reducibility of Pd and Pt species during the reaction. The higher activity of Pt/HFAU catalysts can be attributed to its greater number of active species (especially Pt⁰). Those active species can be more rapidly formed than Pd⁰ by auto reduction during the calcination of Pt precursor. Whatever the metal, the higher the Si/Al ratio of the support, the faster the xylene oxidation and the lower the coke formation. This can be related to the higher proportion of reduced species (Pd⁰ and Pt⁰) formed on the more dealuminated catalyst but also to the hydrophobicity of the support. Indeed, the hydrophobicity of the zeolite play a positive role in the oxidation activity in presence of steam; the higher the Si/Al ratio of the zeolite, the faster the o-xylene oxidation. Thus a catalyst with a low platinum content supported on a hydrophobic zeolite (0.10 Pt/HFAU(100)) allows to oxidising totally o-xylene at 210 °C in presence of steam.     

碳黑预处理对Pt/C催化剂对甲醇氧化电催化活性的影响

直接甲醇燃料电池(DMFC)由于具有较多的优点而受到广泛的关注. 但是碳载Pt (Pt/C)阳极催化剂电催化活性低是限制其应用的一个主要问题. 为了提高Pt/C催化剂对甲醇氧化的电催化性能, 分别用CO₂, 空气, H₂O₂或HNO₃对常用作为载体的Vulcan XC-72碳黑进行预处理. 结果表明, 在用CO₂, 空气, HNO₃, H₂O₂处理的及未处理的碳黑作载体制得的Pt/C催化剂电极上, 甲醇氧化峰的峰电流密度顺序为39, 33, 32, 20和18 mA•cm^－2, 表明用CO₂处理的碳载体制备的Pt/C催化剂对甲醇氧化有最好的电催化活性和稳定性. 其主要原因是用CO₂处理能减少碳黑表面的含氧基团和增加石墨化程度, 而使碳黑的电阻降低及Pt粒子在碳黑上的分散性变好.     

High performance Fe and N-codoped graphene quantum dot supported Pd3Co catalyst with synergistically improved oxygen reduction activity and great methanol tolerance

Designing high-performance and durable non-platinum catalysts as oxygen reduction reaction (ORR) catalysts is still a major barrier of fuel cell commercialization. In this work, simple hydrothermal and impregnation routes were applied to prepare non-platinum Pd-Co bimetallic nano-catalysts such as Fe-N doped graphene quantum dot (Fe-N-GQD) supported Pd₃Co (Pd₃Co/Fe-N-GQD 10 wt%), carbon supported Pd₃Co/C (10 wt%), graphene quantum dot supported Pd₃Co/C (10 wt%). The synthesized catalysts were physico-chemically characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electronmicroscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The electrochemical investigation was carried out in three electrode half-cell system to evaluate the catalyst activity for oxygen reduction reaction (ORR), the tolerance to methanol crossover and durability. In comparison to commercial Pt/C (ETEK, 20 wt%), the Pd₃Co/Fe-N-GQD with lower weight percentage catalyst (∼10 wt%) displayed comparable electrocatalytic activity toward ORR with even higher methanol-tolerance capability and durability. The fabricated Pd₃Co/Fe-N-GQD with (10 wt %) metal loading exhibited only 20% lower activity than Pt/C (ETEK, 20 wt%) toward ORR. Nevertheless the durability study of the catalyst in acidic media showed that the Pd₃Co/Fe-N-GQD preserve 40% of its activity while Pt/C (ETEK, 20 wt%) exhibited only 20% of its initial catalytic activity for ORR. Moreover the activity loss in the presence of methanol (0.1 M) was obtained for Pt/C (ETEK, 20 wt%) and Pd₃Co/Fe-N-GQD 35% and 14%, respectively. To investigate the role of catalyst support, catalytic activities of Pd₃Co/Fe-N-GQD, Pd₃Co/C, Pd₃Co/GQD and Pd/Fe-N-GQD were compared. The results demonstrated superior catalytic activity of Pd₃Co/Fe-N-GQD which could be related to the cocatalytic role of Fe-N-GQD due to the presence numerous of active sites exposed to the reactants.     

Pd black decorated by Pt sub-monolayers as an electrocatalyst for the HCOOH oxidation

Pd black was modified by a very low amount of Pt corresponding to a sub-monolayer (ML). Spontaneous displacement method was employed. The catalysts with 0.02–0.12 ML were characterized by cyclic voltammetry and CO_ads stripping and were tested for HCOOH oxidation under the potentiodynamic and potentiostatic conditions. All the Pt@Pd catalysts were more active for HCOOH oxidation than Pd black. The Pt@Pd with 0.08 ML of Pt exhibited the highest activity with the maximum current density under the potentiodynamic conditions of 8 mA cm^?2 (vs. 2.7 mA cm^?2 on Pd black). Contrasting HCOOH oxidation kinetics on Pt@Pd and Pt@Au catalysts revealed that the current densities are higher, and the poisoning rate is lower on Pt@Pd catalyst. This was ascribed to an optimal strength of the Pt–adsorbate bond when Pt is supported on Pd and to a possible influence of the Pt atoms on the Pd substrate.     

Precisely Controlled Synthesis of Pt-Pd Octahedral Nanoframes as a Superior Catalyst towards Oxygen Reduction Reaction

Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mg_Pt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst (0.20 A/mg_Pt). Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.