Methanol and ethanol electroxidation using Pt electrodes prepared by the polymeric precursor method

Freitas, Renato G.; Santos, Mauro C.; Oliveira, Reinaldo Cunha de; Bulhões, L.O.S.; Pereira, Ernesto C.

doi:10.1016/j.jpowsour.2005.10.002

Cited by 57 publications

(27 citation statements)

References 41 publications

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Section: Resultsmentioning

confidence: 99%

“…24 However, the highest normalized current peak was observed for the solution that contained only methanol, which is most likely due to the CO adsorption step. 33 This step is favored in methanol and oxidizes at the highest positive potentials (in the peak current region).The activity of the PtSn/C (3:1) electrocatalyst for the oxidation of the solutions in the potentiostatic experiments is shown in Figure 2c. The oxidation of the EtOH:MeOH (80:20) solution exhibited the highest normalized current after 1800 seconds.…”

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Electrooxidation of Mixed Ethanol and Methanol Solutions on PtSn/C Electrocatalysts Prepared by the Polymeric Precursor Method

Amorim¹,

Parreira²,

Silva³

et al. 2017

J. Braz. Chem. Soc.

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Different mass ratio proportions of PtSn (m/m) electrocatalysts with 20% metal loading on a carbon support were prepared for use in ethanol:methanol solutions oxidation reactions. PtSn/C (3:1) (91% alloy degree, lattice parameter of 0.399 nm and mean crystallite size 4.8 nm) presented the best activity for oxidation of mixed solutions. The highest normalized current (ethanol:methanol 80:20) was 4.2 mA mg Pt -1 (measured after 1800 seconds at 0.5 V). Therefore, the PtSn/C (3:1) electrocatalyst with an atomic ratio of 65:35 enhanced both the electronic effect and bifunctional mechanism in (ethanol:methanol 80:20), which resulted in the formation of CO 2 at low potentials, as well as the highest amount of by-products than ethanol and methanol. Keywords: electrooxidation, PtSn/C, electrocatalysts, FTIR-ATR in situ, ethanol:methanol solutions IntroductionThe evolution of technology makes the search for new energy sources necessary, preferably using renewable alternative fuels.1,2 The use of PEMFCs (proton exchange membrane fuel cells) that turn chemical energy into electrical energy has been widely studied as an alternative due to its high efficiency and low greenhouse gases emission. [3][4][5] However, PEMFCs have a high cost due to the use of a Pt electrocatalyst and difficulties related to the transport and storage of hydrogen. [6][7][8][9] Therefore, other fuel options, such as methanol and ethanol, [10][11][12][13][14][15] have been studied because they are liquids and have a relatively high energy density. 16 For the methanol oxidation reaction, formaldehyde, formic acid, CO and CO 2 are produced, and methanol is the least reactive among these molecules in production of CO 2 .17 Therefore, the rate-determining step in methanol oxidation to CO 2 is associated with the conversion of methanol to formaldehyde (i.e., oxidation of the first two electrons). In addition, the slow kinetics of methanol as well as its crossover and toxicity are problematic. 18Ethanol can be obtained from biomass and has a higher energy density (8.0 kW h kg -1 ) compared to that of methanol (6.1 kW h kg -1 ), 19,20 but the oxidation of ethanol may involve a complex reaction pathway, and may be produced CO, acetaldehyde, acetic acid, CO 2 as well as 2-carbon intermediates. 21,22 Therefore, a mixture of ethanol and methanol can provide new reaction pathways, which may favor the formation of different intermediates and contribute to more effective electron transfer than that during oxidation in pure solutions. These pathways may improve the electrocatalytic activity. Therefore, investigation of the oxidation reactions of different ratios of these mixed solutions is important for determining the ideal ratio of each alcohol for future use in direct alcohol fuel cells.Based on the study of different ratios of ethanol and methanol mixtures, Wongyao et al. 23 concluded that the PtRu/C electrocatalyst was more efficient than the PtRu-PtSn/C electrocatalyst for mixed solutions in direct alcohol fuel cells. However, in all of the cases, the solutio...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 96%

Electrooxidation of Mixed Ethanol and Methanol Solutions on PtSn/C Electrocatalysts Prepared by the Polymeric Precursor Method

Amorim¹,

Parreira²,

Silva³

et al. 2017

J. Braz. Chem. Soc.

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“…The loading mass of Pt and WO 3 on the GC substrate was finally determined by a chemical analysis using ICP-AES after each electrochemical measurement. The base 4 , in which 0.01 to 1.0 M of EtOH was added to examine the catalytic behavior toward the anodic oxidation of the alcohol at the electrocatalysts. Cyclic voltammetry was conducted with 0.05 V s ¹1 of the potential scanning rate in a nitrogen atmosphere at 30°C.…”

Section: Methodsmentioning

confidence: 99%

Electrocatalytic Activity of Platinum Nano-particle Deposited on Tungsten Oxide for Anodic Oxidation of Ethanol

et al. 2012

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A platinum-tungsten oxide binary electrocatalyst, Pt-WO 3 , has been prepared on a carbon black support to examine the effects of the introduction of WO 3 on the anodic oxidation of ethanol at Pt electrocatalyst. Specific activity for the ethanol oxidation, evaluated from voltammetric responses, was higher at the catalyst deposited on the oxide, Pt-WO 3 /C, than at the catalyst without the oxide, Pt/C. However, no improvement in the continuous activity was observed for the catalyst with WO 3 , suggesting that the effect of WO 3 introduction was limited to the initial step of the anodic oxidation of ethanol at the Pt electrocatalyst.

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“…34 Todos os eletrodos possuíam área geométrica de 3 cm 2 . O sistema para a realização das eletrólises consistia em uma célula eletroquímica com três eletrodos, sendo um ânodo (ADE ou Ti/Pt) e dois cátodos de platina em forma de rede.…”

Section: Eletrodos E Sistema Eletroquímicounclassified

Eletrodegradação de Ponceau 2R utilizando ânodos dimensionalmente estáveis e Ti/Pt

Ribeiro¹,

Oliveira²,

Lima‐Neto³

et al. 2013

Quím. Nova

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Recebido em 23/4/12; aceito em 13/8/12; publicado na web em 27/11/12 ELECTRODEGRADATION OF PONCEAU 2R USING DIMENSIONALLY-STABLE ANODES AND Ti/Pt. This paper reports the electrochemical degradation of the azo dye Ponceau 2R under galvanostatic electrolysis in the 1 to 200 mA cm -2 range at room temperature using dimensionally-stable anodes of oxygen (DSA-O 2 ), chlorine (DSA-Cl 2 ) and a titanium electrode of platinum coated with platinum oxide (Ti/Pt). The methodology applied was efficient for removing the color of the Ponceau 2R and the highest percentage removal of total organic carbon was obtained at 200 mA cm -2 . Despite not having been observed complete mineralization, approximately80% removal of aromatic rings was estimated, resulting in drastic reduction of toxicity of the sample.Keywords: Ponceau 2R; DSA; Ti/Pt. INTRODUÇÃOOs métodos eletroquímicos de degradação de substâncias orgânicas possuem posição de destaque no campo de degradação de poluentes ambientais. 1-3 Os métodos de degradação eletroquímica têm sido aplicados na eliminação de diversos compostos orgânicos, que, presentes na água, são considerados como poluentes, tais como: pesticidas, fármacos e corantes. [4][5][6] Os processos eletroquímicos apresentam como principal vantagem o uso de um "reagente limpo", o elétron, 7 uma vez que evitam a utilização de substâncias tóxicas ao meio ambiente, incluindo, desta maneira, os conceitos da Química Verde. Outras vantagens que podem ser ressaltadas ao se empregar os métodos de degradação eletroquímica são: a versatilidade, a alta eficiência energética, a operação simples e o baixo custo. 8,9 Os métodos eletroquímicos de degradação, baseados nas reações de oxidação, têm se mostrado como poderosas ferramentas para o tratamento de águas contendo poluentes orgânicos. 10 Adicionalmente, a natureza do material a ser utilizado como ânodo influencia na eficiência dos processos de oxidação de compostos orgânicos. A literatura apresenta ampla utilização de ânodos de primeira classe, também conhecidos como ânodos ativos, sendo representados pelos materiais à base de platina, óxidos de irídio (IrO 2 ) e de rutênio (RuO 2 ). 11 No caso dos óxidos, estes pertencem a uma classe de materiais conhecidos como ânodos dimensionalmente estáveis (ADE). Esta designação denota uma classe de eletrodos de óxidos preparados termicamente, onde o substrato de titânio é recoberto pelo óxido métalico. 12 Outros óxidos que podem fazer parte da composição dos ADE são os de tântalo (Ta 2 O 5 ) e de estanho (SnO 2 ). 13 Os ADE apresentam como características: elevada área superficial, estabilidade e acentuada resistência química e mecânica, mesmo em altas densidades de corrente e em meios fortemente ácidos. 14,15 Os ADE são utilizados na indústria de cloro e álcalis e em muitas outras aplicações, como, por exemplo, a eletrólise da água. Os ADE também se mostraram promissores para aplicação na oxidação eletroquímica de poluentes orgânicos presentes em águas residuais. [16][17][18] A utilização de ADE no tratamento de efluentes resultou ...

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Methanol and ethanol electroxidation using Pt electrodes prepared by the polymeric precursor method

Cited by 57 publications

References 41 publications

Electrooxidation of Mixed Ethanol and Methanol Solutions on PtSn/C Electrocatalysts Prepared by the Polymeric Precursor Method

Electrooxidation of Mixed Ethanol and Methanol Solutions on PtSn/C Electrocatalysts Prepared by the Polymeric Precursor Method

Electrocatalytic Activity of Platinum Nano-particle Deposited on Tungsten Oxide for Anodic Oxidation of Ethanol

Eletrodegradação de Ponceau 2R utilizando ânodos dimensionalmente estáveis e Ti/Pt

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