A simple approach for PtNi–MWCNT hybrid nanostructures as high performance electrocatalysts for the oxygen reduction reaction

Du, Shangfeng; Lu, Yaxiang; Malladi, Sairam K.; Xu, Qiang; Steinberger‐Wilckens, Robert

doi:10.1039/c3ta13608f

Cited by 59 publications

(46 citation statements)

References 46 publications

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“…All metallic catalysts were also evaluated in terms of specific activity (SA) and mass activity (MA) (Figures 6c and 6d). The SA and MA are given as kinetic current densities (J k ) at 0.7 V (Figure 6c) and at 0.0 V (Figure 6d) normalized in reference to the loading amount of metal and ECSA, respectively, 52,66 (Table I) was same (∼0.12 mA cm −2 ) at 0.7 V for both catalysts. Very particularly, the AgNCs/rGO_AA, produced MA of 0.38 mA g (at 0.0 V), respectively.…”

Section: 55mentioning

confidence: 99%

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Ahmed

Lee

Kim

2016

J. Electrochem. Soc.

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The silver nanocrystals (AgNCs) anchored on graphene oxide (GO) catalysts have been synthesized by a facile chemical reduction and nontemplate method using ascorbic acid (AA) as reducing agent and have successfully employed as a cathode catalyst for oxygen reduction reaction (ORR) in direct alkaline fuel cells (DAFCs). The morphological characterizations demonstrate that the AgNCs have crystalline form and grafted onto reduced graphene oxide (AgNCs/rGO_AA). Comparatively better dispersion and higher population of AgNCs have observed on AA treated AgNCs/rGO than NaBH 4 which is known as conventional reducing agent. The electrochemical catalysis in 0.1 M KOH electrolyte has demonstrated that the AgNCs/rGO_AA has an excellent electrocatalytic activity for ORR in alkaline media compared to the other tested electrodes. Particularly, it shows 40% higher mass activity with large specific activity against 20 wt% Pt/C with faster electron transfer rate per O 2 . Moreover, the reaction kinetic parameters have confirmed that the ORR at AgNCs/rGO_AA catalyst not only follows a 4e -process with lowering H 2 O 2 formation but also proceeds on with good stability and fuel selectivity in DAFCs. The oxygen reduction reaction (ORR) is an interesting research area and already attracted widespread attention of researches from all over the world because of its important role in the application of energy storage and conversion devices, such as fuel cells (FCs) and metal−air batteries in alkaline media.1-4 Due to superior energy conversion efficiency and potential for providing clean energy, FCs are in the main attention as next generation energy sources. 5,6 As the FCs consists of anode and cathode electrodes, the greatest effect on the performance of FCs is the oxidation/reduction reaction kinetics occurring at the respective electrodes. Unfortunately, the sluggish kinetic rate of ORR at the cathode is the main obligation to be applied in industry. 6 Typically, the platinum (Pt) and/or Pt-based materials are known as the most efficient electrocatalyst in the cathode for ORR catalysis [7][8][9][10] but unfortunately, the Pt-based materials have faced many troubles such as its susceptibility to time dependent drift and CO poisoning, 11,12 slow electron-transfer kinetics, 13 high costs, limited supply, 14 and poor durability. 15 For those reasons, Pt has hindered the widespread commercialization of FCs technology. To overcome the cost challenges, significant efforts have focused on the development of alternative non-Pt catalysts that are based on mainly non-precious metals and/or various heteroatom-doped carbonaceous materials. [16][17][18] Among the non-Pt metal catalysts studied, silver (Ag)-based carbon nanomaterials have been explored as promising candidates with higher activity and stability in alkaline medium recently. [19][20][21][22] According to previous reports, the Ag is an ideal alternative of Pt because it is not only abundantly available in nature and much cheaper but also higher electrical and thermal conductive than Pt....

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Section: 55mentioning

confidence: 99%

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Ahmed

Lee

Kim

2016

J. Electrochem. Soc.

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“…[9][10][11][12][13][14][15][16][17][18][19] In several cases, these materials have exceeded the DOE-MEA target in RDE half-cells.…”

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confidence: 99%

Oxidation of Platinum Nickel Nanowires to Improve Durability of Oxygen-Reducing Electrocatalysts

Alia

Pylypenko

Dameron

et al. 2016

J. Electrochem. Soc.

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The impact of heat treating platinum-coated nickel (Pt-Ni) nanowires in oxygen is examined to determine the effect on oxygen reduction (ORR) activity and durability. Pt-Ni nanowires exhibit promising ORR mass activities (3 times greater than Pt nanoparticles, 1.5 times greater than U.S. Department of Energy target) both before and after potential cycling for all but the highest annealing temperatures explored. The annealing of Pt-Ni nanowires in oxygen with increasing temperature is found to reduce surface area and ORR activity in comparison to the untreated material, but also reduces activity losses following durability testing. Following potential cycling, unannealed Pt-Ni nanowires show significant losses in surface area (23%) and specific activity (18%) while Pt-Ni nanowires annealed at 200 • C show modest increases in surface area (2%) and specific activity (6%) after potential cycling. Increasing annealing temperatures also show a clear trend of decreasing Ni dissolution rates. While oxygen annealing has shown the ability to improve durability of Pt-Ni nanowires, significant Ni dissolution was observed in all samples and suggests oxide passivation while showing promise for improved durability, when employed by itself is insufficient to prevent all contamination concerns involving Ni dissolution. Platinum-nickel (Pt-Ni) nanowires are relatively recent additions to the family of advanced catalysts for fuel cell applications.

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“…Although highly graphitized CNTs possess desirable electrical conductivity, their surface areas are relatively lower than those of CNFs (high surface areas are prerequisites for dispersing active metal components) [28,29]. In addition, carbon nanotubes require functionalization in harsh environments (strongly acidic and oxidizing environments) to introduce active sites [30], whereas CNFs could be used directly as supports because of the existence of abundant defect sites [31].…”

Section: Introductionmentioning

confidence: 99%

“…Hybridization of different active components and supports is a viable approach for improving electrochemical performance because of the potential synergistic effects of the hybridized materials [30,32,33].…”

Section: Introductionmentioning

confidence: 99%

Randomly oriented Ni–P/nanofiber/nanotube composite prepared by electrolessly plated nickel–phosphorus alloys for fuel cell applications

Liu

Jiang

et al. 2017

J Mater Sci

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In this work, we have synthesized a new type of hybridized composites, Ni-P/ CNT-CNFs, which refers to carbon nanotube (CNT)-hybridized carbon nanofibers (CNFs) through electrolessly plated nickel-phosphorus (Ni-P) alloys. The composites combine the merits of CNTs with high electronic conductivity and CNFs with abundant defect sites via the junction of electrolessly deposited Ni-P. The materials have been extensively characterized by scanning electron microscope, transmission electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller (BET), thermogravimetric analysis and hydrophilicity analysis. Electrochemical evaluations for oxygen reduction reaction (ORR) are carried out in 0.1 M KOH with and without 1 M methanol. In addition to serving as desirable candidates as electrocatalyst supports, the randomly oriented hybridized composites show satisfactory activities to ORR and excellent methanol tolerance in alkaline solutions. This generalized method is applicable for the preparation of a broad range of composite materials with different active components simply by variations in electroless plating bath (for example, copper\cobalt or bimetallic plating).

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A simple approach for PtNi–MWCNT hybrid nanostructures as high performance electrocatalysts for the oxygen reduction reaction

Cited by 59 publications

References 46 publications

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

Oxidation of Platinum Nickel Nanowires to Improve Durability of Oxygen-Reducing Electrocatalysts

Randomly oriented Ni–P/nanofiber/nanotube composite prepared by electrolessly plated nickel–phosphorus alloys for fuel cell applications

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