Silver-Carbon Nanocapsule Electrocatalyst for Oxygen Reduction Reaction

Wu, Cheng; Wu, Pu‐Wei; Lin, Pang; Li, Yuan-Yao; Lin, Ying Mei

doi:10.1149/1.2767421

Cited by 35 publications

(23 citation statements)

References 31 publications

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“…From these spectra, the R ct for both La 0. 6 Figure 7 demonstrates the resulting voltage profiles for 10 min. As shown, the voltage plateaus for most of the samples were relatively flat and their values were reasonably consistent with those reported in earlier i-V polarization curves.…”

Section: B902mentioning

confidence: 99%

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Synthesis and Characterization of La[sub 0.6]Ca[sub 0.4]Co[sub 0.8]Ru[sub 0.2]O[sub 3] for Oxygen Reduction Reaction in an Alkaline Electrolyte

Chang

et al. 2010

J. Electrochem. Soc.

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We employed an amorphous citrate precursor ͑ACP͒ method to synthesize stoichiometric La 0.6 Ca 0.4 Co 0.8 Ru 0.2 O 3 powders. Result from X-ray diffraction demonstrated a perovskite La 0.6 Ca 0.4 CoO 3 lattice, indicating the incorporation of Ru 3+ at the Co 3+ sites. Image from the scanning electron microscope revealed a foamlike microstructure with various pores at 0.5-3 m. La 0.6 Ca 0.4 Co 0.8 Ru 0.2 O 3 exhibited a higher H 2 O 2 decomposition rate in KOH solution as opposed to that of ACP-derived La 0.6 Ca 0.4 CoO 3 , which suggested an improved catalytic ability for oxygen reduction reaction ͑ORR͒. A similar behavior was observed during the ORR current-potential polarization using La 0.6 Ca 0.4 Co 0.8 Ru 0.2 O 3 supported on Black Pearl 2000 as a gas diffusion electrode. In addition, impedance spectra at the open-circuit voltage and selective cathodic overpotentials also confirmed a smaller charge-transfer resistance for La 0.6 Ca 0.4 Co 0.8 Ru 0.2 O 3 . In galvanostatic measurements and lifetime evaluation, La 0.6 Ca 0.4 Co 0.8 Ru 0.2 O 3 demonstrated steady voltage profiles with negligible degradation.Oxygen reduction reaction ͑ORR͒ is a critical step in fuel cell electrochemistry because a significant overpotential is often required to activate the relatively stable oxygen molecules. 1 Because conventional fuel cells involve an acidic electrolyte, noble metals and alloys such as Pt and Pt 3 Ni are selected for their chemical inertness. 2,3 However, to reduce the system cost, it is necessary to adopt less expensive materials with comparable performances. 4,5 The ORR in an alkaline electrolyte reveals less polarization loss, leading to a fuel cell with better efficiency. 6 Furthermore, without concerns over acids, less noble metals including Ag, Ni, and Co, as well as oxides of perovskite ͑ABO 3 ͒ and spinel ͑AB 2 O 4 ͒ can be employed as electrocatalysts. 7-11 Among them, lanthanum cobaltate ͑LaCoO 3 ͒ and its derivatives have attracted considerable attention for their simple synthesis and impressive performances. 12,13 In LaCoO 3 the catalytic ability for the ORR is attributed to Co 3+ . To date, a rich variety of transition-metal ions have been explored for partial replacements at the Co 3+ sites to further improve the ORR kinetic. 14-16 Recently, we synthesized La 0.6 Ca 0.4 CoIr 0.25 O 3.5−␦ and La 0.6 Ca 0.4 Co 0.8 Ir 0.2 O 3 and reported improved performances for both the ORR and oxygen evolution reaction over those of La 0.6 Ca 0.4 CoO 3 . 17,18 We realize that the successful incorporation of Ir 4+ at the Co 3+ sites is responsible for the catalytic enhancements. Because metallic Ru is known as an ORR electrocatalyst, 19,20 a similar strategy can be employed to introduce Ru 3+ at the Co 3+ sites for possible catalytic actions. The perovskite lattice is expected to provide a stable platform for hosting Ru 3+ . As a result, a reduced amount of Ru is used, as opposed to the metallic form.In an alkaline electrolyte, the ORR is understood to proceed in two distinct ways. 21 The straightforward route is ...

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Section: B902mentioning

confidence: 99%

“…These curves exhibited typical i-V characteristics where the potential values were found to decrease gradually from 1.6 V with increasing current densities. Among these samples, La 0 6. Ca 0.4 Co 0.8 Ru 0.2 O 3 /BP2000 demonstrated the largest catalytic ability, delivering 1.039 and 0.907 V at 100 and 200 mA/cm 2 , respectively.…”

mentioning

confidence: 99%

Synthesis and Characterization of La[sub 0.6]Ca[sub 0.4]Co[sub 0.8]Ru[sub 0.2]O[sub 3] for Oxygen Reduction Reaction in an Alkaline Electrolyte

Chang

et al. 2010

J. Electrochem. Soc.

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“…The activity of the Pt-group metals for ORR is very high, and some of the most successful catalysts to date (such as Pt/Au cathodes used in the space shuttle) have contained Pt-group metals. However, Pt suffers from slow dissolution in alkaline electrolyte and therefore its stability has been a serious concern [4]. Ag shows ORR activity close to that of Pt [5,6].…”

Section: Introductionmentioning

confidence: 99%

Carbon-Supported Silver as Cathode Electrocatalyst for Alkaline Polymer Electrolyte Membrane Fuel Cells

2011

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Carbon-supported silver in varying percentage viz. 40%, 60%, and 80% (Ag/C) is prepared by sodium citrate protecting method. The structure, dispersion, electrochemical characterization, and surface area and oxygen reduction reaction pathway of Ag/C are determined by XRD, TEM, CV, and LSV, respectively. The catalyst is evaluated for its electrocatalytic activity towards oxygen reduction reaction (ORR) in alkaline polymer electrolyte membrane fuel cells (APEMFCs); 60% Ag/C gives higher performance than 40%, and 80% Ag/C. Metal loading on cathode is optimized through the cell polarization studies using 60% Ag/C. A peak power density of 10 mW/cm 2 is obtained for APEMFC single cell comprising 60% Ag/C and 38% Pt/C as cathode and anode catalysts, respectively.

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“…Transition metals, especially silver, show the ORR catalytic activity in aqueous alkaline media [52][53][54]. This is understandable because in oxygen atmosphere, the transition metals are oxidized into metal oxides, and in this case the transition metals function as an ORR catalyst as their corresponding oxides do.…”

Section: Transition Metals and Alloysmentioning

confidence: 99%

Oxygen Redox Catalyst for Rechargeable Lithium-Air Battery

Zhang

2015

Rechargeable Batteries

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Silver-Carbon Nanocapsule Electrocatalyst for Oxygen Reduction Reaction

Cited by 35 publications

References 31 publications

Synthesis and Characterization of La[sub 0.6]Ca[sub 0.4]Co[sub 0.8]Ru[sub 0.2]O[sub 3] for Oxygen Reduction Reaction in an Alkaline Electrolyte

Synthesis and Characterization of La[sub 0.6]Ca[sub 0.4]Co[sub 0.8]Ru[sub 0.2]O[sub 3] for Oxygen Reduction Reaction in an Alkaline Electrolyte

Carbon-Supported Silver as Cathode Electrocatalyst for Alkaline Polymer Electrolyte Membrane Fuel Cells

Oxygen Redox Catalyst for Rechargeable Lithium-Air Battery

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