Electrochemical Capacitor Behavior of Layered Ruthenic Acid Hydrate

Sugimoto, Wataru; Iwata, Hidehisa; Murakami, Yasushi; Takasu, Yoshio

doi:10.1149/1.1765681

Cited by 90 publications

(48 citation statements)

References 68 publications

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“…The redox peaks between 0.45 and 0.70 V vs. RHE are due to adsorption-desorption of ionic species on the surface of RuO 2 ns. 30,[34][35][36] The peak at 0.11 V vs. RHE is characteristic of a monolayer of RuO 2 nanosheet in H 2 SO 4 and may be due to adsorption-desorption of anionic species (HSO 4 − or SO 4 2− ) on the surface of RuO 2 ns. 29,37 The ECSA for Pt/C was 55 m 2 (g-Pt) −1 .…”

Section: Resultsmentioning

confidence: 99%

Influence of the RuO₂Nanosheet Content in RuO₂Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts

Chauvin

Saida

Sugimoto

2014

J. Electrochem. Soc.

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A series of composite electrocatalysts composed of RuO 2 nanosheets and carbon supported Pt (RuO 2 ns-Pt/C) has been synthesized by mixing different amounts of commercial 50 wt% Pt/C with RuO 2 ns derived from exfoliation of layered K 0.2 RuO 2.1 · nH 2 O. The oxygen reduction activity and stability of the different electrocatalysts has been evaluated as a function of the nanosheet content in the composite electrocatalysts. An increase in initial activity was observed for composite electrocatalyst with RuO 2 /Pt<0.4. After conducting accelerated durability tests, the RuO 2 ns-Pt/C composite electrocatalyst with RuO 2 /Pt = 0.3 exhibited a 25% higher mass activity toward oxygen reduction than the pristine Pt/C electrocatalyst. Carbon supported platinum and platinum-based alloy electrocatalysts are commonly used for the cathode catalyst in polymer electrolyte membrane fuel cells.1 Improved initial electrocatalytic activity and suppression of loss in electrocatalytic activity during fuel cell operation are major obstacles that must be overcome for wide-spread commercialization. It has been suggested that alloys such as Pt with Co, Ru, Fe, Cr or Ni lead to higher oxygen reduction reaction activity due to favorable Pt-Pt distance, electronic structure or Pt crystal orientation.2-12 Unfortunately, the promoter metal can often easily dissolve from the alloy leading to loss in catalytic activity 13 and in some cases damage the polymer electrolyte membrane.14 One way to overcome these drawbacks is to use electrochemically stable oxides as additives. Some metal oxides have been suggested to help oxygen dissociation, promote interaction with Pt, and improve the ionic mobility. 15,16 Metal oxide supported Pt electrocatalyst based on TiO 2 , SnO 2 , RuO 2 or TiO 2 -RuO 2 have also been developed. [17][18][19][20] While most of these composite electrocatalysts show improved durability compared to Pt/C, very few of these electrocatalyst show higher or even comparable initial activity. RuO 2 is one of the few oxides that is an exception, possessing good electronic conductivity and high electrochemical stability within the hydrogen and oxygen evolution region. 21,22 The addition of RuO 2 has been shown to increase the activity toward oxygen reduction by improving the wettability of the catalyst layer due to self-humidification. [23][24][25] The addition of RuO 2 has also been reported to catalyze the oxidation of water, therefore providing protection from other redox active species at high cathode potential. 26 An enhancement in the electronic structure through interaction between Pt and RuO 2 has also been suggested. 27 We have reported the use of RuO 2 nanosheets (RuO 2 ns) with thickness of ∼1 nm as an efficient co-catalyst.22,28 RuO 2 ns has been shown to enhance activity and durability of Pt/C as an anode 29,30 as well as cathode catalyst. 31 In an earlier study, it was shown that the durability of commercial Pt/C (20 mass% of Pt) with ultrasmall Pt (1-1.5 nm) could be improved without sacrificing initial activity. 32Smalle...

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Section: Resultsmentioning

confidence: 99%

Influence of the RuO₂Nanosheet Content in RuO₂Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts

Chauvin

Saida

Sugimoto

2014

J. Electrochem. Soc.

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“…Three characteristic redox pairs are observed at ~0.1, 0.65 and 0.8 V (hereafter denoted A1/C1, A2/C2, A3/C3). A2/C2 and A3/C3 are attributed to electrosorption of anionic and cationic species, respectively [27,28]. A1/C1 is uncommon for polycrystalline RuO 2 systems but bears similarity to peaks observed in high quality RuO 2 (100) single crystal surfaces [38].…”

Section: Electrochemical Properties Of Ruo 2 Ns/cmentioning

confidence: 95%

“…It is well known that crystalline RuO 2 has high electrochemical stability within the hydrogen and oxygen evolution region [23][24][25][26][27][28][29][30]. However, it has also been reported that hydrous ruthenium oxide containing Ru 3+ is not stable in acidic electrolyte [30].…”

Section: Introductionmentioning

confidence: 99%

Enhanced activity and stability of Pt/C fuel cell anodes by the modification with ruthenium-oxide nanosheets

Saida¹,

Sugimoto²,

Takasu³

2010

Electrochimica Acta

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Ruthenium oxide nanosheet (RuO 2 ns) crystallites with thickness less than 1 nm were prepared via chemical exfoliation of a layered potassium ruthenate and deposited onto carbon supported platinum (Pt/C) as a potential co-catalyst for fuel cell anode catalysts. The electrocatalytic activity towards carbon monoxide and methanol oxidation was studied at various temperatures with for different RuO 2 ns loadings. An increase in electrocatalytic activity was evidenced at temperatures above 40°C, while little enhancement in activity was observed at room temperature. The RuO 2 ns modified Pt/C catalyst with composition of RuO 2 :Pt= 0.5:1 (molar ratio) exhibited the highest methanol oxidation activity. CO-stripping voltammetry revealed that RuO 2 ns promotes oxidation of adsorbed CO on Pt. In addition to the enhanced initial activity, the RuO 2 ns modified Pt/C catalyst exhibited improved stability compared to pristine Pt/C against consecutive potential cycling tests.

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“…Therefore, many researchers are focused on improving the energy density of supercapacitors while maintaining their high power density [6][7][8]. The energy storage of pseudocapacitors is based on the Faraday reactions occurring at the surface of electroactive materials, such as RuO 2 , MnO 2 , IrO 2 , and Co 3 O 4 [9][10][11][12][13], and the energy density is higher than carbon based electric double-layer capacitors. Transition metal oxides provide higher specific capacitance and energy density than carbon materials [14,15], which have been considered as promising pseudocapacitive materials.…”

Section: Introductionmentioning

confidence: 99%

Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

Zhang

Liu

et al. 2017

Journal of Nanomaterials

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Transition metal phosphide alloys possess the metalloid characteristics and superior electrical conductivity and are a kind of high electrical conductive pseudocapacitive materials. Herein, high electrical conductive cobalt phosphide alloys are fabricated through a liquid phase process and a nanoparticles structure with high surface area is obtained. The highest specific capacitance of 286 F g −1 is reached at a current density of 0.5 A g −1 . 63.4% of the specific capacitance is retained when the current density increased 16 times and 98.5% of the specific capacitance is maintained after 5000 cycles. The AC//CoP asymmetric supercapacitor also shows a high energy density (21.3 Wh kg −1 ) and excellent stability (97.8% of the specific capacitance is retained after 5000 cycles). The study provides a new strategy for the construction of high-performance energy storage materials by enhancing their intrinsic electrical conductivity.

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Electrochemical Capacitor Behavior of Layered Ruthenic Acid Hydrate

Cited by 90 publications

References 68 publications

Influence of the RuO₂Nanosheet Content in RuO₂Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts

Influence of the RuO₂Nanosheet Content in RuO₂Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts

Enhanced activity and stability of Pt/C fuel cell anodes by the modification with ruthenium-oxide nanosheets

Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

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Electrochemical Capacitor Behavior of Layered Ruthenic Acid Hydrate

Cited by 90 publications

References 68 publications

Influence of the RuO2Nanosheet Content in RuO2Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts

Influence of the RuO2Nanosheet Content in RuO2Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts

Enhanced activity and stability of Pt/C fuel cell anodes by the modification with ruthenium-oxide nanosheets

Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

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Influence of the RuO₂Nanosheet Content in RuO₂Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts

Influence of the RuO₂Nanosheet Content in RuO₂Nanosheet-Pt/C Composite Toward Improved Performance of Oxygen Reduction Electrocatalysts