Tantalum oxide-based electrocatalysts made from oxy-tantalum phthalocyanines as non-platinum cathodes for polymer electrolyte fuel cells

Uehara, Naoki; Ishihara, Akimitsu; Matsumoto, Masashi; Imai, Hideto; Kohno, Yuji; Matsuzawa, Koichi; Mitsushima, Shigenori; Ota, Ken Ichiro

doi:10.1016/j.electacta.2015.03.125

Cited by 19 publications

(15 citation statements)

References 20 publications

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“…The Ota group managed to deposit small Ta 2 O 5 particles (<10 nm) on multiwalled carbon nanotubes using organometallic complex oxy-tantalum phthalocyanine (TaOC 32 H 16 N 8 ) as the precursor. 523 The carbon film on the metal oxide particles formed during heat treatment acted as an electric conducting medium improving the activity of Ta 2 O 5 , but also a barrier covering the active sites. Thus, the amount and structure of the carbon film played a significant role in determining the activity of the metal oxide particles.…”

Section: Metal Oxides Nitrides Oxynitrides and Carbonitridesmentioning

confidence: 99%

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

et al. 2016

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The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core-shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.

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Section: Metal Oxides Nitrides Oxynitrides and Carbonitridesmentioning

confidence: 99%

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

et al. 2016

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“…The k 1 /k 2 ratios for the Pt catalyst and TaC x N y O z /MWCNT were 5 and 8, respectively. 3,5 In terms of the selectivity of the reaction, the TiC x N y O z /MWCNTs were superior to the Pt catalyst and the TaC x N y O z /MWCNTs.…”

Section: Resultsmentioning

confidence: 99%

“…3 The RRDE consisted of a glassy carbon disk (6.0 mm in diameter) surrounded by a platinum ring with an internal diameter of 7.0 mm and an external diameter of 9.0 mm. The catalyst was supported on the disc electrode at a loading of ca.…”

Section: Methodsmentioning

confidence: 99%

Kinetic Study of Oxygen Reduction Reaction in Acid Solution Using Titanium Oxide-based Catalysts Prepared from Oxy-titanium Tetra-pyrazino-porphyrazine

et al. 2015

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Oxide-based electrocatalysts were investigated as non-platinum cathodes for the oxygen reduction reaction (ORR). Recently, we found that titanium oxide-based compounds produced from oxy-titanium tetra-pyrazino-porphyrazine via oxidation under low oxygen partial pressure exhibited high ORR activity [T. Hayashi et al., ECS Trans., 64(3), 247 (2014)]. However, the mechanism by which the ORR proceeds in the presence of titanium oxide-based catalysts has not yet been analyzed in detail. In this study, the ORR mechanism was investigated based on the Damjanovic model by using a rotating ring disk electrode. The titanium oxide-based catalysts showed high reactivity in the four electron reduction of O 2 .

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“…Oxygen reduction reaction (ORR) is one of the most important reactions in renewable energy conversion of defects such as oxygen vacancies. [12,[19][20][21][22] As illustrated in Table S1, Supporting Information, [16,18,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] the activity of this class of materials is still low, that is, they require high overpotential even to achieve a modest current density, and do not reach the limiting current value expected for the reduction of oxygen to water by the four-electron pathway:…”

Section: Introductionmentioning

confidence: 99%

Engineering of a Low‐Cost, Highly Active, and Durable Tantalate–Graphene Hybrid Electrocatalyst for Oxygen Reduction

Zhang

Sebastián

Zhang

et al. 2020

Advanced Energy Materials

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and storage devices, such as fuel cells and metal-air batteries. [1][2][3][4][5][6][7][8] Especially, the polymer electrolyte membrane fuel cells, used in automotive applications, have already achieved the level of commercialization. [5] Although the Pt group metal (PGM) catalysts can efficiently address the kinetics-related challenges, the high cost and the limited resource of PGM greatly hinder the widespread commercialization of these energy conversion and storage devices. Therefore, the development of low-cost, highly active, and stable PGM-free catalysts, to replace the PGM ones, toward ORR, is highly desired. Over the past decades, extensive research was devoted to the development of alternative and low-cost catalysts, including i) non-precious Fe and Co-based metal catalysts, [3,4,[9][10][11] ii) metal oxides, nitrides, and oxynitrides, [12][13][14] and iii) metal-free catalysts such as carbon-based materials. [15] Oxides from metals belonging to groups 4 and 5 (Ti, V, Zr, Nb, Hf, Ta) have attracted interest in these fields, mainly due to their low cost compared to PGM catalysts, environmental compatibility, and excellent stability in acid medium. [12,[16][17][18][19] It has been demonstrated that these oxides can have some activity toward ORR, if their stoichiometry is conveniently tailored to generate a high concentration The oxygen reduction reaction (ORR) is one of the most important reactions in renewable energy conversion and storage devices. The full deployment of these devices depends on the development of highly active, stable, and low-cost catalysts. Herein, a new hybrid material consisting of Na 2 Ta 8 O 21−x / Ta 2 O 5 /Ta 3 N 5 nanocrystals grown on N-doped reduced graphene oxide is reported. This catalyst shows a significantly enhanced ORR activity by ≈4 orders of magnitude in acidic media and by ≈2 orders of magnitude in alkaline media compared to individual Na 2 Ta 8 O 21−x on graphene. Moreover, it has excellent stability in both acid and alkaline media. It also has much better methanol tolerance than the commercial Pt/C, which is relevant to methanol fuel cells. The high ORR activity arises not only from the synergistic effect among the three Ta phases, but also from the concomitant nitrogen doping of the reduced graphene oxide nanosheets. A correlation between ORR activity and nitrogen content is demonstrated. Deep insights into the mechanism of the synergistic effect among these three Ta-based phases, which boosts the ORR's kinetics, are acquired by combining specific experiments and density functional theory calculations.

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Tantalum oxide-based electrocatalysts made from oxy-tantalum phthalocyanines as non-platinum cathodes for polymer electrolyte fuel cells

Cited by 19 publications

References 20 publications

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

Kinetic Study of Oxygen Reduction Reaction in Acid Solution Using Titanium Oxide-based Catalysts Prepared from Oxy-titanium Tetra-pyrazino-porphyrazine

Engineering of a Low‐Cost, Highly Active, and Durable Tantalate–Graphene Hybrid Electrocatalyst for Oxygen Reduction

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