Improvements in electrical and electrochemical properties of Nb-doped SnO<sub>2−δ</sub> supports for fuel cell cathodes due to aggregation and Pt loading

Senoo, Yuichi; Kakinuma, Katsuyoshi; Uchida, Makoto; Uchida, Hiroyuki; Deki, Shigehito; Watanabe, Masahiro

doi:10.1039/c4ra03988b

Cited by 62 publications

(113 citation statements)

References 40 publications

(46 reference statements)

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“…The value of jk of Pt/TiC-600 °C at 0.85 V was 0.70 mA cm −2 , which was approximately 1.4 times higher than that of cPt/CB. Similar enhancement factors of the jk were also reported for Pt/Nb-SnO2−δ and Pt/Ta-SnO2−δ [29,30]. The value of MA of Pt/TiC-600 °C at 0.85 V (507 A g ), since the ECA of Pt/TiC-600 °C was smaller than that of c-Pt/CB.…”

Section: Electrochemical Characterization Of Pt/tic Catalystssupporting

confidence: 79%

“…By TEM observation, we have clearly demonstrated that the major reason for such a high durability of Pt/TiC-600 °C was suppression of the detachment of Pt particles from the support, unlike c-Pt/CB. Hence, based on our systematic work using various ceramic supports (TiN [26], doped SnO2 [27][28][29][30], and TiC in the present work), the essential factors for the highly active and highly durable cathode catalysts are the use of a chemically and electro chemically stable support with high electrical conductivity, uniform dispersion of Pt nanocrystals on the support, and the removal of an oxide layer, if any, on the Pt surface and/or Pt-ceramic support interface.…”

Section: Discussionmentioning

confidence: 99%

“…They reported that Pt-dispersed Nb-SnO2−δ and Ta-SnO2−δ exhibited both higher ORR activity and higher durability at high potentials than those for commercial Pt/CB (c-Pt/CB) catalysts. It was also found that the kinetically controlled specific ORR activities on various Pt/Nb-SnO2−δ catalysts increased with increasing apparent electrical conductivity of the support [29].…”

Section: Introductionmentioning

confidence: 89%

“…The support materials used are typically in the form of nanoparticles with HSA to disperse Pt catalyst particles uniformly, but the use of HSA supports often leads to a high contact resistance between the particles. Recently, Kakinuma et al have developed Sb-, Nb-and Ta-doped SnO2−δ nanoparticle supports with a fused aggregated structure having both HSA and low contact resistance [27][28][29][30]. They reported that Pt-dispersed Nb-SnO2−δ and Ta-SnO2−δ exhibited both higher ORR activity and higher durability at high potentials than those for commercial Pt/CB (c-Pt/CB) catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

et al. 2015

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Abstract:We have prepared Pt nanoparticles supported on titanium carbide (TiC) (Pt/TiC) as an alternative cathode catalyst with high durability at high potentials for polymer electrolyte fuel cells. The Pt/TiC catalysts with and without heat treatment were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Hemispherical Pt nanocrystals were found to be dispersed uniformly on the TiC support after heat treatment at 600 °C in 1% H2/N2 (Pt/TiC-600 °C). The electrochemical properties (cyclic voltammetry, electrochemically active area (ECA), and oxygen reduction reaction (ORR) activity) of Pt/TiC-600 °C and a commercial Pt/carbon black (c-Pt/CB) were evaluated by the rotating disk electrode (RDE) technique in 0.1 M HClO4 solution at 25 °C. It was found that the kinetically controlled mass activity for the ORR on Pt/TiC-600 °C at 0.85 V (507 A g ). Moreover, the durability of Pt/TiC-600 °C examined by a standard potential step protocol (E = 0.9 V↔1.3 V vs. RHE, holding 30 s at each E) was much higher than that for c-Pt/CB. OPEN ACCESSCatalysts 2015, 5 967

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Section: Electrochemical Characterization Of Pt/tic Catalystssupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

et al. 2015

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“…[30][31][32][33] Briefly, reagent grade 2-ethylhexanoate salts of Sn and Ta (Nihon Kagaku Sangyo, Co. Ltd.) were mixed at desired ratios into turpentine oil. The mixtures were supplied into the burner (>1000…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Oxidation of Hydrolyzed Poly-Oxymethylene-Dimethylether by Pt and PtRu Catalysts on Ta-Doped SnO₂Supports for Direct Oxidation Fuel Cells

Kakinuma

Hirayama

Iiyama

et al. 2017

J. Electrochem. Soc.

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We synthesized Pt and PtRu catalysts supported on Ta-doped SnO 2 (Pt/Ta-SnO 2 , PtRu/Ta-SnO 2 ) for the anodes of direct oxidation fuel cells fueled with poly-oxymethylene-dimethylether (POMM n , n = 3∼8). The onset potential for the oxidation of the hydrolyzed fuel of POMM 3 (h-POMM 3 ; methanol-formaldehyde mixtures with the composition equivalent to 100% hydrolyzed POMM 3 ) on Pt/Ta-SnO 2 and PtRu/Ta-SnO 2 was at least 0.2 V lower than that on a commercial Pt 2 Ru 3 /carbon black (c-Pt 2 Ru 3 /CB). The Pt-based mass activities at 0.50 V (MA 0.50V ) of PtRu/Ta-SnO 2 for the h-POMM 3 and formaldehyde oxidations were more than four times larger than those of the c-Pt 2 Ru 3 /CB. Elemental tin was found to exist on the top surface, brought by the diffusion from the Ta-SnO 2 support. The elemental tin may contribute to enhancing the anodic reaction via an acceleration of carbon monoxide oxidation by a bifunctional mechanism or ligand effect. Single cells using Pt/Ta-SnO 2 and PtRu/Ta-SnO 2 as anodes exhibited higher current densities in all voltage regions when supplied with the h-POMM 3 fuels dissolved in water. We deduced that both the elemental tin diffusion from the Ta-SnO 2 support to the catalyst nanoparticles and the unique fused-aggregate network structure of the Ta Polymer electrolyte fuel cells (PEFCs) supplied directly with liquid fuels are suitable as power sources for various portable applications with extended operating time. Liquid alcohol fuels such as methanol and ethanol are attractive energy carriers with environmental compatibility, good energy density and low cost. 1-6The liquid oligomers of poly-oxymethylene-dimethylethers (POMM n : CH 3 -O-(CH 2 -O) n -CH 3 , n = 3∼8) have also been proposed as an alternative class of liquid fuels for the future, 7 but they have several hurdles to clear before they can enjoy widespread use. Fortunately, the POMM n preparation from methane has already been established as an industrial process, with the methane feedstock existing on a massive scale as natural gas and even as a by-product from oil wells.8 The POMM n compounds have been applied as raw materials of the polyacetal resins used in vehicle parts and medical devices. [8][9][10] A project on the application of POMM n has been conducted in Germany. 8 The POMM n compounds have no corrosive properties for steels used containers of various sizes, including tankers. Other attractive properties are non-toxicity, high flash points (>64• C) and high boiling temperatures (ca. 100• C), unlike methanol. In addition, the POMM n compounds can easily and immediately hydrolyze under acidic conditions to form methanol and formaldehyde (Eq. 1):7,11-13Thus, the POMM n class of compounds is becoming one of the more promising candidates for new energy carriers for use in fuel cells, and the essential properties described above have the potential to lower the hurdle of cost, to improve the safety, and to maintain a stable supply, in comparison with other energy carriers such as methanol, even with increasing demand for POM...

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Small Angle X‐Ray Scattering Study for Investigating the 3D Packing Structure of Pt Catalysts on Gd‐Doped CeO₂ Supports for Fuel Cells

Omote,

Iwata,

Kakinuma

2023

Advcd Theory and Sims

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A 3D structural model for fuel cell catalysis systems is constructed, which consist primarily of Pt and CeO2 nanoparticles, to fit observed small angle X‐ray scattering (SAXS) patterns by using the reverse Monte–Carlo (RMC) method. The observed SAXS patterns are well reproduced by those of the simulations. Pore size distributions using the obtained structure models are compared with the Barrett–Joyner–Halenda (BJH) analysis for the nitrogen gas adsorption data, and the lower quartiles and medians of the pore diameters are reasonably consistent. In addition, analysis of the SAXS patterns indicates that the number of nanometer‐size Pt particles is much smaller than that of the introduced amount. This suggests that most Pt particles are not uniformly distributed in the catalysis system.

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Improvements in electrical and electrochemical properties of Nb-doped SnO_2−δ supports for fuel cell cathodes due to aggregation and Pt loading

Abstract: We found the specific activities of Pt/Sn0.96Nb0.04O2−δ for the oxygen reduction reaction increased with increasing conductivity of the support.

Cited by 62 publications

References 40 publications

Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

Electrochemical Oxidation of Hydrolyzed Poly-Oxymethylene-Dimethylether by Pt and PtRu Catalysts on Ta-Doped SnO₂Supports for Direct Oxidation Fuel Cells

Small Angle X‐Ray Scattering Study for Investigating the 3D Packing Structure of Pt Catalysts on Gd‐Doped CeO₂ Supports for Fuel Cells

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Improvements in electrical and electrochemical properties of Nb-doped SnO2−δ supports for fuel cell cathodes due to aggregation and Pt loading

Abstract: We found the specific activities of Pt/Sn0.96Nb0.04O2−δ for the oxygen reduction reaction increased with increasing conductivity of the support.

Cited by 62 publications

References 40 publications

Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

Electrochemical Oxidation of Hydrolyzed Poly-Oxymethylene-Dimethylether by Pt and PtRu Catalysts on Ta-Doped SnO2Supports for Direct Oxidation Fuel Cells

Small Angle X‐Ray Scattering Study for Investigating the 3D Packing Structure of Pt Catalysts on Gd‐Doped CeO2 Supports for Fuel Cells

Contact Info

Product

Resources

About

Improvements in electrical and electrochemical properties of Nb-doped SnO_2−δ supports for fuel cell cathodes due to aggregation and Pt loading

Electrochemical Oxidation of Hydrolyzed Poly-Oxymethylene-Dimethylether by Pt and PtRu Catalysts on Ta-Doped SnO₂Supports for Direct Oxidation Fuel Cells

Small Angle X‐Ray Scattering Study for Investigating the 3D Packing Structure of Pt Catalysts on Gd‐Doped CeO₂ Supports for Fuel Cells