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Bron, Michael; Fiechter, S.; Hilgendorff, M.; Bogdanoff, Peter

doi:10.1023/a:1014753613345

Cited by 116 publications

(84 citation statements)

References 32 publications

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“…Another approach is to develop methanol-tolerant cathode catalysts such as binary platinum alloys containing Co, Ni, Fe and Cr [5][6][7]. Various transition-metal macrocycles [8][9][10] and ruthenium-based chalcogenides [11,12] have also been tested as methanol-tolerant oxygen cathodes because these compounds are inactive toward the oxidation of methanol. However, the catalytic activities of these catalysts for the oxygen-reduction reaction (ORR) are still lower than those of Pt-based catalysts, and the long-term stability under fuel cell conditions at high potentials has not been well tested as compared to Pt-based catalysts [13].…”

Section: Introductionmentioning

confidence: 99%

Pt–Sn/C as a Possible Methanol-Tolerant Cathode Catalyst for DMFC

et al. 2013

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An effective method was developed for preparing highly dispersed nano-sized Pt-Sn/C electrocatalyst synthesised by a modified polyol reduction method. From XRD patterns, the Pt-Sn/C peaks shifted slightly to lower 2θ angles when compared with commercial Pt/C catalyst, suggesting that Sn formed alloy with Pt. Based on HR-TEM images, the PtSn/C nanoparticles showed small particle sizes and well dispersed onto the carbon support with a narrow particle distribution. The methanol oxidation reaction on the asprepared Pt-Sn/C catalyst appeared at lower currents (+7.08 mA at +480 mV vs. Ag/AgCl) compared to the commercial Pt/C (+8.25 mA at +480 mV vs. Ag/AgCl) suggesting that the Pt-Sn/C catalyst has 'methanol tolerance capabilities'. Pt-Sn/C HA Slurry pH3 catalysts showed better activity towards the oxygen-reduction reaction (ORR) than commercial Pt/C which could be attributed to smaller particle sizes. In our study, the Pt-Sn/C catalyst appears to be a promising methanol-tolerant catalyst with activity towards the ORR in the DMFC. IntroductionIn recent years, considerable attention and R&D funding have been injected into direct methanol fuel cell (DMFC) technologies. There are a large number of applications for DMFCs especially in stationary devices, portable electrical devices and transportation [1]. The use of methanol as a fuel has a few advantages in comparison to hydrogen. For example, methanol is an inexpensive liquid fuel which can be easily transported, stored and handled [1,2]. However, despite these advantages and progress made in the development of DMFCs, the performance is still limited due to the poor kinetics of both anode and cathode reaction and the methanol crossover from the anode to the cathode side through the polymer electrolyte membrane (PEM) [3,4]. In many cases, this methanol crossover issue decreases the fuel cell efficiency and produces mixed currents due to methanol oxidation on the cathode side, resulting in cell voltage losses [2][3][4]. Moreover, the crossover effect in the DMFC membrane causes a further decrease in the cathode efficiency due to the occurrence of a mixed potential, which results from the competitive reaction between oxygen reduction and methanol oxidation on Pt cathode [5]. To avoid this problem, one strategy is to modify the existing membranes or to develop novel membranes with less methanol permeability. Another approach is to develop methanol-tolerant cathode catalysts such as binary platinum alloys containing Co, Ni,. Various

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Section: Introductionmentioning

confidence: 99%

Pt–Sn/C as a Possible Methanol-Tolerant Cathode Catalyst for DMFC

et al. 2013

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“…It is worth to note the Fe content of the Fe-N/CB sample before acid treatment was around 2.6 wt.%, close to the optimum value for Fe-Phen catalyst for the ORR. 13 As the molar amount of starting iron was the same for all M-Fe catalyst during the synthesis procedure, it can be supposed that Fe contents before acid treatment were around 2.6 wt.% for all samples reported in this work. After acid treatment at 353 K, the Fe content in this sample dramatically decreased to about 0.4 wt.%, indicating that most of the iron was dissolved during the acid treatment.…”

Section: Resultsmentioning

confidence: 71%

“…13,14 As a nitrogen-bearing organic compound, 1,10-phenanthroline (Phen) can form a stable complex with Fe 2+ , and Fe-N x species derived from an Fe 2+ -phen complex could also serve as highly active sites for ORR. 13,15,16 Dodelet's group proposed that pyridinic-type nitrogen in the structure of a phenanthroline can coordinate with the Fe ion in a catalytic active site, and N-bearing functionalities can bind cations to the micropores on carbon black (CB) particles. 12,14 A catalytic site consisting of an iron cation coordinated by four pyridinic functionalities can provide a high ORR activity, comparable to that of platinum, but the stability remains unsatisfactory because of the disappearance 17 or degradation 18 of catalytic sites in harsh acidic and/or oxidizing conditions.…”

mentioning

confidence: 99%

Electrocatalytic Activity and Stability of M-Fe Catalysts Synthesized by Polymer Complex Method for PEFC Cathode

Ou¹,

Kumagai²,

Yin³

et al. 2011

J. Electrochem. Soc.

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The polymerized complex (PC) method was used to synthesize highly dispersed iron-based catalysts for the oxygen reduction reaction (ORR). The catalysts were prepared with an addition of 1,10-phenanthroline (Phen) and transition metals (M), such as Ta, Ti, and W, in an attempt to enhance the ORR activity and durability of the catalysts. The composition and properties of the catalysts were characterized by thermogravimetric analysis, X-ray diffraction, and X-ray photoelectron spectroscopy. The catalyst components, after extensive dissolution in a strong acid solution, were characterized by inductively coupled plasma mass spectroscopy and ultraviolet-visible spectroscopy. It was found that the Ti-Fe catalyst showed improved ORR performance, and the Ta-Fe catalyst showed enhanced stability towards ORR in acidic solution. The catalytic activity and stability for ORR was observed by adding Ti or Ta into the catalyst formulation, suggesting that the interaction between added hetero-ions (Ti and Ta) and ionic Fe active sites was beneficial for the ORR. A single-cell test with the synthesized catalyst in the cathode initially generated a high power density, but the low stability remains an issue to be solved.

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“…Similar results of metal loading effect have been discussed in previous literature. [21] Over-loading metal may lead to the formation of particles with no activity. And the inactive metals, metal oxides, and metal carbides hinder the reactants entering the pores of carbon support.…”

Section: Catalyst Activitymentioning

confidence: 99%

Aerobic Oxidation of Hydroxymethylfurfural and Furfural by Using Heterogeneous Co_xO_y–N@C Catalysts

et al. 2014

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2,5-Furandicarboxylic acid (FDCA) is considered to be a promising replacement for terephthalic acid since they share similar structures and properties. In contrast to FDCA, 2,5-furandicarboxylic acid methyl (FDCAM) has properties that allow it to be easily purified. In this work, we reported an oxidative esterification of 5-hydroxymethylfurfural (HMF) and furfural to prepare corresponding esters over Cox Oy -N@C catalysts using O2 as benign oxidant. High yield and selectivity of FDCAM and methyl 2-furoate were obtained under optimized conditions. Factors which influenced the product distribution were examined thoroughly. The Cox Oy -N@C catalysts were recycled five times and no significant loss of activity was detected. Characterization of the catalysts could explain such phenomena. Using XPS and TGA, we made a thorough investigation of the effects of ligand and pyrolysis temperature on catalyst activity.

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Cited by 116 publications

References 32 publications

Pt–Sn/C as a Possible Methanol-Tolerant Cathode Catalyst for DMFC

Pt–Sn/C as a Possible Methanol-Tolerant Cathode Catalyst for DMFC

Electrocatalytic Activity and Stability of M-Fe Catalysts Synthesized by Polymer Complex Method for PEFC Cathode

Aerobic Oxidation of Hydroxymethylfurfural and Furfural by Using Heterogeneous Co_xO_y–N@C Catalysts

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Untitled

Cited by 116 publications

References 32 publications

Pt–Sn/C as a Possible Methanol-Tolerant Cathode Catalyst for DMFC

Pt–Sn/C as a Possible Methanol-Tolerant Cathode Catalyst for DMFC

Electrocatalytic Activity and Stability of M-Fe Catalysts Synthesized by Polymer Complex Method for PEFC Cathode

Aerobic Oxidation of Hydroxymethylfurfural and Furfural by Using Heterogeneous CoxOy–N@C Catalysts

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Aerobic Oxidation of Hydroxymethylfurfural and Furfural by Using Heterogeneous Co_xO_y–N@C Catalysts