Partially oxidized niobium carbonitride as a non-platinum catalyst for the reduction of oxygen in acidic medium

Nam, Kyung Don; Ishihara, Akimitsu; Matsuzawa, Koichi; Mitsushima, Shigenori; Ota, Ken Ichiro; Matsumoto, Masashi; Imai, Hideto

doi:10.1016/j.electacta.2010.07.048

Cited by 40 publications

(25 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, in recent reports 2,8,9 about tantalum oxide-based ORR catalysts, it has been indicated that a surface oxygen vacancy behaves as an active site owing to its property of attracting oxygen molecule. Figure 9 is the plots of j S of Pb 2 Ru 2 O 7-δ heat-treated respective temperature as a function of δ, indicating that Pb 2 Ru 2 O 7-δ which contained more oxygen vacancies showed higher area specific activity.…”

Section: Discussion About Active Site For Orr and Effect Of Solution mentioning

confidence: 99%

“…While many types of non-platinum electrocatalyst have been reported, such as metal-oxides, metal macrocyclic complex, metal chalcogenides, and nitrogen-containing carbon, none of them has been applied to practice due to poor performance or durability. [1][2][3][4][5][6][7][8][9][10][11][12] We have been focusing on lead-ruthenium oxide (Pb 2 Ru 2 O 7-δ ) as a candidate of non-platinum electrocatalyst for ORR. [13][14][15][16] Pb 2 Ru 2 O 7-δ has a pyrochlore-type structure with some oxygen vacancies, and shows high electronic conductivity.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Effects of Oxygen Vacancies and Reaction Conditions on Oxygen Reduction Reaction on Pyrochlore-Type Lead-Ruthenium Oxide

Fujii

Satô

Takase

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

A series of pyrochlore-type lead-ruthenium oxide (Pb 2 Ru 2 O 7-δ ) containing various amounts of oxygen vacancies was prepared by varying the heat-treatment temperature, and the oxygen reduction reaction (ORR) activity as well as the electrochemical redox property in acid and alkaline solution was evaluated using rotating disk electrode. The specific ORR activity was increased with increasing the amount of oxygen vacancies, and linearly correlated to the charge amount of electrochemical redox of Pb 2 Ru 2 O 7-δ both in acid and alkaline solution. We concluded that the surface oxygen vacancy participates in the electrochemical redox of Pb 2 Ru 2 O 7-δ , and at the same time, behaves as the active site for ORR. The ORR activity in alkaline solution was much higher than that in acid solution, possibly because of the difference of the facility of electrochemical desorption of adsorbed oxygen species in the ORR process. Additionally, the effect of humidity on the ORR activity was investigated by single cell test. Proton exchange membrane fuel cells (PEMFCs) are promising alternative power sources for home co-generation system and transportation applications due to advantages such as low emission and high efficiency. There are, however, still many problems remaining for widespread commercialization of PEMFCs. In the current PEMFCs, platinum based catalyst is used as the cathode electrocatalyst for oxygen reduction reaction (ORR). From the view of cost and availability, alternative electrocatalyst to platinum is strongly required. While many types of non-platinum electrocatalyst have been reported, such as metal-oxides, metal macrocyclic complex, metal chalcogenides, and nitrogen-containing carbon, none of them has been applied to practice due to poor performance or durability. 1-12We have been focusing on lead-ruthenium oxide (Pb 2 Ru 2 O 7-δ ) as a candidate of non-platinum electrocatalyst for ORR. [13][14][15][16] Pb 2 Ru 2 O 7-δ has a pyrochlore-type structure with some oxygen vacancies, and shows high electronic conductivity. [17][18][19][20][21][22][23][24][25][26] Horowitz et al. 20 have firstly reported that Pb 2 Ru 2 O 7-δ which is prepared by co-precipitation method in aqueous solution and post heat-treatment at 300-750• C shows high ORR activity in alkaline solution. Afterwards, several researches aimed at application of Pb 2 Ru 2 O 7-δ to electrochemical devices such as fuel cell, metal-air battery and oxygen sensor have been conducted. 20,21,[27][28][29][30][31][32][33][34] For example, Goodenough et al. 31,35 have reported that Pb 2 Ru 2 O 7-δ shows ORR activity and high stability not only in alkaline solution but also in acid solution and proton exchange membrane such as Nafion. Also, we have found that partial substitution of other cations such as Bi, In, or Sb with Pb site in Pb 2 Ru 2 O 7-δ have a positive effect on the ORR activity.13 Nevertheless, the ORR activity of Pb 2 Ru 2 O 7-δ is needed to be drastically enhanced for practical use as the cathode electrocatalyst of PEMFC. For this purpose, it ...

show abstract

Section: Discussion About Active Site For Orr and Effect Of Solution mentioning

confidence: 99%

mentioning

confidence: 99%

Effects of Oxygen Vacancies and Reaction Conditions on Oxygen Reduction Reaction on Pyrochlore-Type Lead-Ruthenium Oxide

Fujii

Satô

Takase

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…On the other hand, group 4 and 5 metal oxide compounds are regarded as promising candidates for PEFC cathode catalysts, because they are insoluble in acidic media and are much less expensive than platinum. Oxide compounds based on zirconium, − tantalum, , titanium, − and niobium have been developed by different synthetic routes.…”

Section: Introductionmentioning

confidence: 99%

Emergence of Oxygen Reduction Activity in Zirconium Oxide-Based Compounds in Acidic Media: Creation of Active Sites for the Oxygen Reduction Reaction

et al. 2019

Self Cite

View full text Add to dashboard Cite

To develop zirconium oxide-based electrocatalysts for the oxygen reduction reaction (ORR), we attempted to clarify the factors that affect the ORR activity of oxide-based cathodes. We prepared zirconium oxide-based electrocatalysts from oxy-zirconium phthalocyanine with multiwalled carbon nanotubes as electroconductive supports via heat treatment under a low oxygen partial pressure. We evaluated the density of the active sites, i.e., oxygen vacancies, using X-ray photoelectron spectroscopy (XPS), the average particle size of the oxide particles using a transmission electron microscopy (TEM), and the surface area utilization of the oxide particles using TEM image analysis. We successfully determined that the increase in the ORR activity was due to the increase in the density of oxygen vacancies and the effective surface area and that the decrease in the effective surface area was responsible for the decrease in the ORR activity. In addition, we performed hard X-ray photoemission spectroscopy (HAXPES) analysis to understand the process by which the active sites were created. A comparison of the XPS and HAXPES results revealed that the oxygen vacancies were concentrated near the surface during heat treatment under a low oxygen partial pressure via the oxidation of the deposited carbon. The deposited carbon plays a role in creating ORR-active oxygen vacancy sites and promoting ORR by providing local nanoscale conduction paths on the relatively insulating oxide surfaces.

show abstract

“…Ongoing efforts toward engendering nonprecious metal electrocatalysts for oxygen reduction reaction (ORR) have resulted in various catalyst configurations, including (a) metal–nitrogen–carbon network (Zelenay et al and Dodelet et al), − (b) transition-metal nitrides/oxynitrides (Ota et al. ), − and (c) transition metal-chalcogen cluster compounds. − Catalysts of type (a) comprise carbon as the major constituent, with trace amounts of active metals (<5% by weight). These catalysts have appreciable ORR activity comparable to that of Pt/C in acid. , However, high carbon content restrains the use of these catalysts in SAFC owing to both poor mass transport considerations and carbon corrosion.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical and In Situ Spectroscopic Evidences toward Empowering Ruthenium-Based Chalcogenides as Solid Acid Fuel Cell Cathodes

Ghoshal

Jia

et al. 2016

ACS Catal.

View full text Add to dashboard Cite

A low-cost Ru-based chalcogenide catalyst has been used as a cathode catalyst in solid acid fuel cells (SAFC). With sequential addition of Se and Mo on Ru/C in a controlled manner, the resulting physical and electrochemical properties have been discussed in detail. The oxygen reduction reaction (ORR) in the presence of phosphoric acid has been performed to appraise the tolerance of the catalyst in the presence of phosphate anions. Considering the phosphate-rich environment during cell operation, this study is especially relevant for designing catalysts for s. In order to estimate the coverage of phosphate anions on active sites, a semiquantitative analysis of the corresponding Tafel plots has been done. Electrochemical, thermogravimetric, and in situ X-ray absorption spectroscopic experiments have been performed to get a deeper perception of the catalyst–electrolyte interface and account for the high stability of the chalcogenide catalyst at room temperature as well as at elevated temperature. Steady-state polarization curves in SAFC have been collected for over 120 h using the chalcogenide catalyst operating at 250 °C.

show abstract

Partially oxidized niobium carbonitride as a non-platinum catalyst for the reduction of oxygen in acidic medium

Cited by 40 publications

References 41 publications

Effects of Oxygen Vacancies and Reaction Conditions on Oxygen Reduction Reaction on Pyrochlore-Type Lead-Ruthenium Oxide

Effects of Oxygen Vacancies and Reaction Conditions on Oxygen Reduction Reaction on Pyrochlore-Type Lead-Ruthenium Oxide

Emergence of Oxygen Reduction Activity in Zirconium Oxide-Based Compounds in Acidic Media: Creation of Active Sites for the Oxygen Reduction Reaction

Electrochemical and In Situ Spectroscopic Evidences toward Empowering Ruthenium-Based Chalcogenides as Solid Acid Fuel Cell Cathodes

Contact Info

Product

Resources

About