Graphite-nanofiber-supported porous Pt–Ag nanosponges: Synthesis and oxygen reduction electrocatalysis

Lee, Chien‐Liang; Chao, Yi-Ju; Chen, Chi-Hao; Chiou, Hsueh-Ping; Syu, Chia-Chieh

doi:10.1016/j.ijhydene.2011.08.066

Cited by 19 publications

(18 citation statements)

References 15 publications

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“…To deeply explore the ORR kinetics over these catalysts, the kinetic current densities (J k ) were calculated from the ORR polarization curves by mass-transport correction and normalized to the loading amount of two metals in order to compare the mass-specific activities of these catalysts. In our case, the nanostructure-sensitive ORR activity for these Pt-Ag bimetallic catalysts most likely 21 results from the modifications of the electronic structures within the synthesized bimetallic materials, which changes the interaction energy between oxygen and the catalysts, that is, the rate controlling step for ORR, and results in the improved ORR kinetics [34,35]. 5c.…”

Section: Electrocatalytic Activity For Orr On These Pt-ag Bimetallic mentioning

confidence: 96%

A novel strategy to synthesize bimetallic Pt–Ag particles with tunable nanostructures and their superior electrocatalytic activities toward the oxygen reduction reaction

et al. 2016

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The ability to precisely control the nanoscale phase structure of bimetallic catalysts is required to achieve a synergistic effect between two metal for oxygen reduction reaction (ORR). In this work, we synthesized Pt-Ag bimetallic nanoparticles (NPs) with Ag@Pt core-shell, highly alloyed solid and hollow nanostructures respectively, via a galvanic replacement reaction by modifying H 2 PtCl 6 concentration in an aqueous solution containing homemade Ag NPs as the sacrificial templates. The nanophase and corresponding electronic structures of the synthesized Pt-Ag NPs were characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The formation of these Pt-Ag NPs with different 2 nanophase structures is closely ascribed to a defect-induced Kirkendall effect that involves the accelerated interdiffusion of Ag and Pt atoms, triggered by the high density of defects along the Ag NP surface generated by the galvanic replacement reaction. The nanophase structure-dependent electrocatalytic activity of three Pt-Ag bimetallic NPs was determined in 0.5 M H 2 SO 4 solution by using a rotating disk electrode (RDE). The results showed that the core-shell and hollow alloy NPs exhibit the excellent ORR activity in an acidic solution, which is remarkably higher than that of the commercial Pt/C (E-TEK). The physical origin of the enhancement in the ORR activity can be explained by a mutual ligand effect, raised by the substantial electronic transfer between Pt and Ag at the atomic level, which results from the downshift of the d-band center for Pt and the increased number of the unpaired electrons for Ag in these bimetallic catalysts. Thus two factors achieve a synergistic effect that dominates the remarkably improved electrocatalytic activity for the ORR.

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Section: Electrocatalytic Activity For Orr On These Pt-ag Bimetallic mentioning

confidence: 96%

A novel strategy to synthesize bimetallic Pt–Ag particles with tunable nanostructures and their superior electrocatalytic activities toward the oxygen reduction reaction

et al. 2016

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“…[28,29] The precise control of chiral photoreactions or photochirogenesis is one of the most challenging topics in current photochemistry. A supramolecular approach to photochirogenes provides a convenient and also promising tool to facilitate excited-state chirality transfer from chiral host to prochiral substrate…”

Section: Moura and Lagomentioning

confidence: 99%

“…Boscolo et al reported that the high catalytic performances of Pseudomonas fluorescens lipase adsorbed on a new type of cyclodextrin-based NSs. [28] As a carrier for delivery of gases Gases play an important role in medicine for diagnostic or the treatment purposes. The deficiency of more oxygen supply, named hypoxia, is related to various pathologies, from inflammation to that of cancer.…”

Section: Arkas Et Almentioning

confidence: 99%

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Pawar

2016

AJP

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The invention of nanosponges (NSs) has become a significant step toward overcoming the problems associated with conventional drug delivery. NS drug delivery system has emerged as one of the most promising fields in life science. These small sponges circulate around the body until they encounter the target site and stick on the surface and began to release the drug in a controlled and predictable manner which is more effective for a particular given dosage. The development of new colloidal carrier called NSs has the potential to solve these problems. Both lipophilic and hydrophilic drugs can be loaded in NSs. NS is a novel and emerging technology which offers controlled drug delivery for topical use. They can be crafted for targeting drugs to a specific site, prevent drug and protein degradation, and prolong the drug release in a controlled manner. NSs play a key role in targeting drug delivery in a controlled manner. In this review article, application of NSs, its preparation methods, and evaluation have been discussed.

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“…Generally, the catalytic properties of the electrocatalysts are affected by the specific area, stacking density, electrical conductivity and electrochemical oxidation resistance of carbon supports, which are various with their shapes and structures [3] . Different carbon materials have been used as catalyst carriers, such as carbon black [4][5] , carbon nanotube (CNT) [6][7] , carbon nanofiber [8][9][10] , Graphene sheet [11][12][13] and so on. Vulcan XC72 carbon black has been most widely used to support metal nanoparticles because of its high surface area and low electrical resistance.…”

Section: Introductionmentioning

confidence: 99%

Construction of a high-performance air-breathing cathode using platinum catalyst supported by carbon black and carbon nanotubes

Xiong¹,

Liao²,

Hou³

et al. 2016

International Journal of Hydrogen Energy

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It is well recognized that pore structure and the hydrophilicity/ hydrophobicity balance are key factors for the cathodes of air-breathing proton exchange membrane fuel cells (AB-PEMFCs). In this work, we attempted to adjust the pore structure and hydrophilicity of an air-breathing cathode by using two types of catalysts, Pt/C and Pt/CNT, to prepare the catalyst layer for the air-breathing cathode instead of using a single catalyst. An MEA with the dual-catalyst cathode exhibited significantly improved single-cell performance, which was affected by the ratio of Pt/C to Pt/CNT. Our optimized MEA, which had a ratio of 54:46 in the cathode catalyst layer, achieved a current density of up to 290 mA cm-2 at 0.6 V, which was 14 % higher than that of a MEA without Pt/CNT. The Pt/CNT in the catalyst layer played the key role in the overall performance of the AB-PEMFC. We propose that the CNT improved charge transfer and enabled better electrical conductivity than carbon black. In addition, the tubular structure of Pt/CNT made the catalyst layer more porous and permeable to gas. Furthermore, the addition of Pt/CNT may have changed the cathode's hydrophilicity/hydrophobicity balance, giving the cathode better water balance and consequently yielding better performance.

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Graphite-nanofiber-supported porous Pt–Ag nanosponges: Synthesis and oxygen reduction electrocatalysis

Cited by 19 publications

References 15 publications

A novel strategy to synthesize bimetallic Pt–Ag particles with tunable nanostructures and their superior electrocatalytic activities toward the oxygen reduction reaction

A novel strategy to synthesize bimetallic Pt–Ag particles with tunable nanostructures and their superior electrocatalytic activities toward the oxygen reduction reaction

Untitled

Construction of a high-performance air-breathing cathode using platinum catalyst supported by carbon black and carbon nanotubes

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