Electrooxidation of CO and methanol on well-characterized carbon supported PtxSn electrodes. Effect of crystal structure

Herranz, T.; Garcia, Sergio O.; Martı́nez-Huerta, M.V.; Peña, M.A.; Fierro, J.L.G.; Somodi, Ferenc; Borbáth, Irina; Majrik, Katalin; Tompos, András; Rojas, Sergio

doi:10.1016/j.ijhydene.2011.11.131

Cited by 43 publications

(26 citation statements)

References 45 publications

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“…All prepared materials showed the particles well dispersed on the support, even though some particle agglomerations can be observed. The nanoparticles' mean diameter was determined by counting about 200 randomly chosen particles from the relevant TEM images [30,31] and the particles are with an average diameter of 4 nm for all Rh content catalyst, and 6 nm for Pt/C. The particles sizes measured are in accordance with similar materials described in literature [20,24,32].…”

Section: Resultsmentioning

confidence: 69%

Electrochemical and in situ ATR-FTIR studies of ethanol electro-oxidation in alkaline medium using PtRh/C electrocatalysts

Fontes

Piasentin

Ayoub

et al. 2015

Mater Renew Sustain Energy

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Pt/C, Rh/C and PtRh/C electrocatalysts with different Pt:Rh atomic ratios supported on Vulcan XC 72 carbon were prepared using borohydride as reducing agent and tested for ethanol electro-oxidation in alkaline medium. X-ray diffraction patterns showed the formation of PtRh alloy. Transmission electron micrographs showed the nanoparticles with particle sizes between 3 and 6 nm for all materials. Electrochemical experiments showed PtRh/C (50:50) the most promising material for ethanol electrooxidation; however, in situ ATR-FTIR experiments was observed that the ethanol oxidation is incomplete due to the formation of acetate and carbonate.

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Section: Resultsmentioning

confidence: 69%

Electrochemical and in situ ATR-FTIR studies of ethanol electro-oxidation in alkaline medium using PtRh/C electrocatalysts

Fontes

Piasentin

Ayoub

et al. 2015

Mater Renew Sustain Energy

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“…Our results demonstrate [20][21][22] that upon using CSRs tin anchoring onto the parent 40 wt.% Pt/C resulted in an alloy-type Sn-Pt/C catalysts, which were highly active in both the electrooxidation reactions of CO and C 1 -C 2 alcohols. In these studies a clear correlation between the Pt 3 Sn alloy phase content and the electrocatalytic performance has been established.…”

mentioning

confidence: 65%

“…Reaction (1) was performed in a 40 ml stainless steel autoclave at 170°C and P H2 = 5 bar using five consecutive tin anchoring periods. The steps of the modification process are described in recent publications [21,22]; for the convenience of the reader they are also outlined in the Supplementary Material.…”

Section: Synthesis Of Sn Modified Pt/c Catalystsmentioning

confidence: 99%

“…In these studies a clear correlation between the Pt 3 Sn alloy phase content and the electrocatalytic performance has been established. It has been shown that the optimal balance between the Pt/Sn ratio, the amount of the fcc Pt 3 Sn alloy phase and the metal particle size are responsible for the activity increase in both the CO and alcohol electrooxidation [20][21][22].…”

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confidence: 99%

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CO oxidation and oxygen reduction activity of bimetallic Sn–Pt electrocatalysts on carbon: effect of the microstructure and the exclusive formation of the Pt3Sn alloy

Gubán

Tompos

Bakos

et al. 2017

Reac Kinet Mech Cat

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Electronic supplementary material:The online version of this article (doi: 10.1007/s11144-017-1152-8) contains supplementary material, which is available to authorized users. Abstract Alloy-type Sn-Pt/C electrocatalysts with desired Pt/Sn= 3.0 ratio have been prepared by Controlled Surface Reactions using home-made 20 wt.% Pt/C (20Pt/C) catalysts with different Pt dispersion. Reaction conditions were found for the preparation of highly dispersed 20Pt/C catalysts by modified NaBH 4 -assisted ethylene-glycol reduction method using ethanol as a solvent. It has been demonstrated that the increase of the heating time in ethanol up to 2 h results in decreasing dispersion of Pt. Upon using highly dispersed 20Pt/C catalyst the exclusive incorporation of Sn onto the Pt sites was achieved resulting in exclusive formation of the Pt-Sn alloy phase. According to in situ XPS studies pre-treatment of the air exposed catalyst in H 2 even at 170°C resulted in complete reduction of the ionic tin to Sn 0 , suggesting alloy formation. In contrast, the catalyst with lower Pt dispersion cannot be completely reduced even at 350°C, as 10 % of tin still remains in the form of Sn 4+ surface species. The electrocatalytic performance of both Sn-20Pt/C catalysts in the CO electrooxidation and the oxygen reduction reaction is superior to that of the parent 20Pt/C catalysts. Our data obtained for the oxygen reduction reaction indicate that the small size of the bimetallic nanoparticles in the highly dispersed Sn-20Pt/C catalyst, along with their optimal surface composition, result in increased activity compared to the catalyst with lower dispersion.Keywords SnPt/C electrocatalysts, Controlled surface reactions, Pt 3 Sn, Oxygen reduction reaction, CO electrooxidation IntroductionPolymer electrolyte membrane fuel cells (PEMFC) offer a very promising solution for environmentally sustainable electric power generation in mobile applications. A major challenge in PEMFC development is the choice of the cathode and anode electrocatalysts, which usually consist of platinum supported on carbon. The Pt/C system is, however, prone to corrosion at high potentials occurring during rapid load change conditions, and sensitive to poisoning by CO, which is a common low level impurity of the hydrogen fuel. As a result, electrocatalysts with acceptable lifetime can only be manufactured with very high Pt loadings. Therefore, a main development goal is to find electrocatalysts with reduced Pt content, enhanced long term stability under operating conditions and affordable price. CO tolerance of the anode electrocatalysts also has to be improved, as CO adsorbs very strongly on Pt, blocking the active sites for the hydrogen oxidation reaction and causing a large decrease in the electrode performance. In order to reduce this poisoning issue, a common approach consists of the utilization of a second oxophilic metal such as Ru, Mo, Ni or Sn [1][2][3][4][5], which are less noble than Pt and thus activate water at lower potential leading to accelerated CO 2

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“…Thus, Colmati et al [54] observed a positive correlation between the MOR activity and the Sn-Pt alloying degree, and pointed Pt 75 Sn 25 /C (or Pt 3 Sn/C) as slightly better catalyst for MOR than Pt 90 Sn 10 /C or Pt/C; Further increasing in Sn-alloying content from Pt 3 Sn/C to PtSn/ C, however, does not increase activity toward MOR [55] because it leads to a phase change from fcc (Pt 3 Sn) to hcp (PtSn) being hcp phase less active toward MOR.…”

Section: The Oxidation Of Methanol On Platinum-tin Catalystsmentioning

confidence: 99%

Catalysts for Methanol Oxidation

González

Mota-Lima

2013

Direct Alcohol Fuel Cells

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Methanol electroxidation proceeds via a multistep reaction. Herein, mechanisms of reaction and reaction rates of sub-set of the mechanism on different surfaces are discussed. Platinum is a reasonable catalyst for the first methanol electroxidation steps (dehydrogenation), but not for the last (CO electroxidation). Hence, alloying Platinum with a second metal was used as a strategy to enhance the rate of the last step. Accordingly, enhanced rates of CO electroxidation are attained by modifying the bonding energy of the adsorbate to the catalyst or by promoting the formation of oxygenated species at lower overvoltage. Finally, new perspectives on the field of methanol catalysts are commented including the search for catalysts that promote early onset of oscillations, i.e. under lower overvoltage. IntroductionMethanol is the typical fuel with one carbon (C1) atom for fuel cells. Methanol was one of the first small molecules chosen to study the oxidation on platinum group metals in the very early beginning of electrocatalysis. In that time, the oxidation of other C1 molecules such as formic acid and formaldehyde (interest in CO oxidation came latter with the oxidation of reformatted gases) were investigated as a model oxidation because their elementary steps were supposedly present in the mechanism of methanol oxidation. From the point of view of CO 2 emission, methanol has, among the other small molecules, the highest energy production per unit of produced

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Electrooxidation of CO and methanol on well-characterized carbon supported PtxSn electrodes. Effect of crystal structure

Cited by 43 publications

References 45 publications

Electrochemical and in situ ATR-FTIR studies of ethanol electro-oxidation in alkaline medium using PtRh/C electrocatalysts

Electrochemical and in situ ATR-FTIR studies of ethanol electro-oxidation in alkaline medium using PtRh/C electrocatalysts

CO oxidation and oxygen reduction activity of bimetallic Sn–Pt electrocatalysts on carbon: effect of the microstructure and the exclusive formation of the Pt3Sn alloy

Catalysts for Methanol Oxidation

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