In situ ATR-FTIR study of bulk CO oxidation on a polycrystalline Pt electrode

Hanawa, Hidehito; Kunimatsu, K.; Uchida, Hiroyuki; Watanabe, Masahiro

doi:10.1016/j.electacta.2009.05.061

Cited by 25 publications

(96 citation statements)

References 76 publications

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“…Also noted is that the abnormal "rise and drop" of the CO B band at the initial stage of the main CO oxidation in Fig. 2 was attributed to the diffusion of CO L from terrace sites to step edge sites to form CO B thereon in the absence of Cl − [28]. The absence of such a conversion of CO L to CO B in the presence of Cl − can be related to the specific adsorption of Cl − which blocks the CO L diffusion to these sites.…”

Section: Resultsmentioning

confidence: 94%

“…On the other hand, Samjeské et al [27] depicted a model in which CO oxidation initiated at steps and proceeded with the diffusion of terrace CO to steps based on the assumption made by Lebedeva et al [6] that CO diffused fast on Pt. Coincidently, Hanawa et al observed a transient rise of the CO B band intensity before its main oxidation, which was ascribed to the diffusion of CO L from terraces to step edges with the subsequent formation of CO B there [28]. Recently, CO diffusion on stepped Pt(1 1 1) was studied by STM and the results showed that steps provided fast diffusion channels for CO [29].…”

Section: Resultsmentioning

confidence: 96%

“…Note that the origin of the prewave has not arrived at a consensus: models were proposed including preferential oxidation of CO B [28], oxidation of weakly adsorbed CO [30], and partial oxidation of CO L triggered by potential-induced site conversion of CO B [27], etc. Nevertheless, in any case, the OH ad is essential for the oxidation of either CO L or CO B .…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Surface-enhanced IR spectroscopy investigation on the electro-oxidation of CO adlayer at a polycrystalline Pt film electrode in Cl−-containing HClO4

Peng

Yan

Cai

2010

Electrochimica Acta

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Surface-enhanced IR spectroscopy investigation on the electro-oxidation of CO adlayer at a polycrystalline Pt film electrode in Cl−-containing HClO4

Peng

Yan

Cai

2010

Electrochimica Acta

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“…However, this is not a favored process on Pt and only happens at potentials more positive than 0.4 V vs RHE in acid [42,43] and alkaline [44,45]. In order for the reactions to proceed, the anode potential has to be higher than this which decreases the total cell voltage.…”

Section: Pt-based Catalysismentioning

confidence: 99%

Silicon nanograss as micro fuel cell gas diffusion layer

et al. 2010

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Direct methanol fuel cells (DMFC) produce electrical energy directly from chemical energy. They are a promising candidate for power sources of portable devices due to the high energy density of methanol and the quick recharging procedure by fuel insertion. However, the problem areas of the DMFC are the slow electro-oxidation of methanol and the permeated methanol reacting at the cathode. New catalysts are constantly searched but they are often tested only for catalytic activity and the DMFC testing is omitted even though the catalyst layer (CL) structure has a large impact on the performance. Miniaturization of the system is also necessary for portable applications. Silicon etching can be used to fabricate small structures for fuel cells replacing or enhancing the functions of laboratory-scale components.In the first part of this thesis, new catalysts for the DMFC are studied with the emphasis on the CL structure. Different carbon supports for the anode were studied: standard carbon black and alternative few-walled carbon nanotubes (FWCNT) and graphitized carbon nanofiber (GNF). The alternative supports showed better DMFC performance but their stability was lower than with carbon black. However, the CL formed with GNF showed a very porous structure enhancing the mass transfer, so that higher binder content could be used improving the stability to the level of carbon black and the performance by 30%. The FWCNTs were also investigated as a platform for enzymatic methanol oxidation by studying the electrochemical properties of an immobilized cofactor pyrroloquinoline quinone (PQQ). A large amount of PQQ was adsorbed having a strong redox response and good stability in a wide pH window. For the cathode, a methanol-tolerant, Pt-free nitrogen-doped FWCNTs were tested in an alkaline DMFC as such testing is not often made. Its performance was remarkably 4 times better than with Pt when synthetic air was used as the oxidant.In the second part of thesis, an integrated gas diffusion layer (GDL) consisting of Si nanoneedles (nanograss) was tested in a micro fuel cell (MFC). The layer functioned properly at low current densities. For high power applications, a standard carbon cloth GDL was tested with the nanograss as a contact surface reducing the resistance between the GDL and the flow field. The use of the nanograss improved the MFC performance and stability. Finally, the MFCs were used as a catalyst testing platform and the results were compared with a similar test in a laboratory-scale DMFC. The results varied showing that the DMFC components also have a large impact on catalyst testing.Keywords direct methanol fuel cell, carbon nanomaterials, micro fuel cells, catalyst layer Tiivistelmä Suorametanolipolttokennot (SMPK) tuottavat sähköenergiaa suoraan kemiallisesta energiasta. Ne ovat lupaava vaihtoehto kannettavien laitteiden voimanlähteeksi, koska metanolilla on korkea energiatiheys ja lataaminen tapahtuu nopeasti polttoainelisäyksellä. SMPK:lla on kuitenkin rajoitteina metanolin hidas hapetusreaktio ja katodi...

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“…[1][2][3][4] For PEFC anode and cathode catalysts, the activity and its degradation have been analyzed by multilateral techniques such as X-ray photoelectron spectroscopy combined with an electrochemical cell (EC-XPS), 2,[5][6][7][8] in situ Fourier-transform infrared spectroscopy (FTIR), [9][10][11][12][13][14][15][16][17][18][19][20][21][22] electrochemical quartz crystal microbalance (EQCM), [23][24][25][26] in situ scanning tunneling microscopy (STM), [27][28][29][30][31] in addition to conventional electrochemical measurements such as rotating disk electrode (RDE), [32][33][34] channel flow electrode (CFE), 21,35,36 and channel flow double electrode (CFDE) methods. [37][38][39][40][41][42] Based on these results, new practical catalysts have been synthesized.…”

Section: Introductionmentioning

confidence: 99%

Research and Development of Highly Active and Durable Electrocatalysts Based on Multilateral Analyses of Fuel Cell Reactions

Uchida

2017

Electrochemistry

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In order to establish clear strategies for the design of electrocatalysts with high activity and high durability, fuel cell reactions have been analyzed by multilateral techniques. The use of monodisperse Pt or Pt-alloy nanocatalysts with uniform composition, which were highly dispersed over the whole surface of the carbon support by the nanocapsule method, contributed greatly in clarifying the effects of various properties (particle size, composition, and surface structure, etc.) towards the activity and durability for the anode and cathode in polymer electrolyte fuel cells (PEFCs). New catalyst layers have been developed in order to make the electrocatalysts work effectively specifically under low humidity. Several important concepts have been demonstrated for developing high-performance oxygen and hydrogen electrodes with high durability for a reversible solid oxide cell (R-SOC), which is expected to be a reciprocal direct energy converter between hydrogen and electricity with high efficiency.

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In situ ATR-FTIR study of bulk CO oxidation on a polycrystalline Pt electrode

Cited by 25 publications

References 76 publications

Surface-enhanced IR spectroscopy investigation on the electro-oxidation of CO adlayer at a polycrystalline Pt film electrode in Cl−-containing HClO4

Surface-enhanced IR spectroscopy investigation on the electro-oxidation of CO adlayer at a polycrystalline Pt film electrode in Cl−-containing HClO4

Silicon nanograss as micro fuel cell gas diffusion layer

Research and Development of Highly Active and Durable Electrocatalysts Based on Multilateral Analyses of Fuel Cell Reactions

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