Niobium-doped titanium oxide for fuel cell application

Thanh, Bui Xuan; Cai, Mei; Ruthkosky, Martin S.; Moylan, Thomas E.

doi:10.1016/j.electacta.2010.03.027

Cited by 36 publications

(30 citation statements)

References 29 publications

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“…Titanium dioxide is promising candidate as catalyst support in PEMFC because TiO 2 has very good chemical stability in acidic and oxidative environments [6,7]. However, undoped TiO 2 oxide is an n-type semiconductor with low electron conductivity and doping with transition metals (e.g., W, Nb and Ta) has been used to enhance its electrical conductivity [8][9][10][11]. Table 1 reports data on the actual composition and preparation details of the Ti (1-x) Mo x O 2 -C (x= 0.2-0.4) composites.…”

Section: Introductionmentioning

confidence: 99%

Effect of Mo incorporation on the electrocatalytic performance of Ti–Mo mixed oxide–carbon composite supported Pt electrocatalysts

Vass

Borbáth

Pászti

et al. 2017

Reac Kinet Mech Cat

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Section: Introductionmentioning

confidence: 99%

Effect of Mo incorporation on the electrocatalytic performance of Ti–Mo mixed oxide–carbon composite supported Pt electrocatalysts

Vass

Borbáth

Pászti

et al. 2017

Reac Kinet Mech Cat

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“…In order to improve the durability of PEFCs in FCVs, the use of higher stability support materials, such as graphitized CB 32 or metal oxides [16][17][18][19][20][21][22][23][24][25][26] is an effective approach to inhibit the COR during the H 2 -SU/SD process. Based on the COR mechanisms (i), (ii) and (iii), the uniform distribution of the ionomer in the cathode CL prevents both the inhibition of H 2 supply and the shortage of H + which cause the COR associated with the reduction of the Pt oxide and the ORR.…”

Section: Resultsmentioning

confidence: 99%

“…13 One approach to mitigate the decrease of the cell performance is to use transition metal oxide support materials, for example, titanium-based oxides [16][17][18][19][20] and tin-based oxides. [21][22][23][24][25][26] Shintani et al proposed that that the reverse current during SU/SD can be decreased by decreasing the ORR current generation on the Ta-doped TiO 2 -supported Pt anode due to its high resistivity in air. 27 In order to clarify the degradation mechanism of the cathode catalysts during SU/SD, Ishigami et al visualized the distribution of the oxygen partial pressure at the anode in real time and space during the SU/SD.…”

mentioning

confidence: 99%

Degradation Mechanisms of Carbon Supports under Hydrogen Passivation Startup and Shutdown Process for PEFCs

Yamashita

Itami²,

Takano³

et al. 2017

J. Electrochem. Soc.

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The use of a hydrogen purge for startup and shutdown (H 2 -SU/SD) process of polymer electrolyte fuel cells has been proposed, which suppresses the generation of internal current during the SU/SD, process so-called "reverse current", and the severe carbon oxidation reaction (COR) in the cathode. However it was found that the COR was still caused during this H2-SU/SD process, even though it was less severe than that during the usual SU/SD process, i.e., the anode gas was successively cycled between air and H 2 . In order to clarify the mechanisms of the COR, we investigated (1) the effect of the presence of Pt catalyst, (2) the timing, and (3) the effect of Pt oxidation state. These results indicated that the COR was accelerated by the Pt catalyst in the cathode and was decelerated with increasing cathode potential during the H 2 -SU/SD process. We propose that the COR is caused by a shortage of protons associated with both the reduction of the Pt oxide and the oxygen reduction reaction at the reduced Pt. Polymer electrolyte fuel cells (PEFCs) convert chemical energy directly to electrical energy with low emissions and high energy efficiency and have shown promise to be an eco-friendly power source for fuel cell vehicles (FCVs) and residential co-generation systems. [1][2][3] Nevertheless, PEFCs still have several problems to be solved, such as limited lifetime and reliability and high cost, before large-scale commercialization can be realized. [4][5][6] The minimization of the PEFC cost can be achieved by improving the specific mass activity (MA) of the catalyst for the oxygen reduction reaction (ORR) at the cathode. The conventional cathode catalysts have consisted of Pt nanoparticles dispersed on high surface area carbon black supports (Pt/CB) to maximize the electrochemically active surface area (ECSA) for the ORR. 4 However, as is widely known, Pt/CB cathode catalysts are degraded under PEFC operating conditions such as load change cycles and startup/shutdown (SU/SD) cycles due to a combination of processes, which include ECSA loss due to the agglomeration or dissolution of Pt nanoparticles, [6][7][8][9][10][11][12] and the corrosion of the CB support material. 7,[11][12][13][14][15] During the SU/SD cycles, air and H 2 coexist transiently in the anode until the replacement of the former with the latter (or vice versa) is completed. Reiser et al. showed that this situation causes the cathode potential to climb to more than 1.5 V due to the so-called "reverse current mechanism", which significantly accelerates the degradation of the catalyst due to the oxidation of the CB and the agglomeration or dissolution of the Pt nanoparticles. 12 The latest papers on this topic have been reviewed. 13 Several approaches have been taken to both understand and mitigate the decrease of PEFC performance during operation.13 One approach to mitigate the decrease of the cell performance is to use transition metal oxide support materials, for example, titanium-based oxides [16][17][18][19][20] and tin-based oxides. [21][22][23][...

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“…It is well known that the Magneli phase Ti 4 O 7 has been widely used in the coating materials of catalysts, fuel cell applications,, lead‐acid batteries due to its good conductivities, high oxygen evolution potential and relatively high corrosion‐resistivity in aggressively acidic and alkaline electrolytes . It has In this work, we found that Ti 4 O 7 as an additive can effectively enhance the electrochemical activity and improve the stabiltiy of Ti/PbO 2 anode.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Photoelectrocatalytic Performance of Ti/PbO₂ Electrodes Modified with Ti₄O₇

Wang

Tian

et al. 2018

ChemistrySelect

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The Ti 4 O 7 modified Ti/PbO 2 electrodes have been prepared by electrodeposition, and investigated systemically using scanning electron microscope (SEM), Energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (XRD), photoluminescence spectroscopy (PL), and degradation of anthraquinone dye (reactive brilliant blue KNÀR: C 22 H 16 N 2 Na 2 O 11 S 3 ). It is found that the Ti 4 O 7 modified Ti/PbO 2 electrodes possessed smaller PbO 2 crystal grains, good porous structure, enhanced oxygen evolution over-potential and higher electrical conductivity, as compared to that of Ti/PbO 2 electrode. Additionally, the Ti 4 O 7 modified Ti/PbO 2 electrode exhibited also longer accelerated lifetime, and higher photoelectrocatalytic activity for degradation of anthraquinone dye (reactive brilliant blue KNÀR) than that of Ti/PbO 2 electrode. The enhancement of the decolorization efficiency and stability for Ti 4 O 7 modified Ti/PbO 2 electrodes can be ascribed to the large electrochemical active areas, the presence of photoelectric synergism, rapid separation of photogenerated carriers, inhibition of oxygen precipitation, high current efficiency for formation of hydroxyl radicals, and the weakening of internal stress in PbO 2 coatings.

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Niobium-doped titanium oxide for fuel cell application

Cited by 36 publications

References 29 publications

Effect of Mo incorporation on the electrocatalytic performance of Ti–Mo mixed oxide–carbon composite supported Pt electrocatalysts

Effect of Mo incorporation on the electrocatalytic performance of Ti–Mo mixed oxide–carbon composite supported Pt electrocatalysts

Degradation Mechanisms of Carbon Supports under Hydrogen Passivation Startup and Shutdown Process for PEFCs

Preparation and Photoelectrocatalytic Performance of Ti/PbO₂ Electrodes Modified with Ti₄O₇

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Niobium-doped titanium oxide for fuel cell application

Cited by 36 publications

References 29 publications

Effect of Mo incorporation on the electrocatalytic performance of Ti–Mo mixed oxide–carbon composite supported Pt electrocatalysts

Effect of Mo incorporation on the electrocatalytic performance of Ti–Mo mixed oxide–carbon composite supported Pt electrocatalysts

Degradation Mechanisms of Carbon Supports under Hydrogen Passivation Startup and Shutdown Process for PEFCs

Preparation and Photoelectrocatalytic Performance of Ti/PbO2 Electrodes Modified with Ti4O7

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Preparation and Photoelectrocatalytic Performance of Ti/PbO₂ Electrodes Modified with Ti₄O₇