Beneficial effects of rhodium and tin oxide on carbon supported platinum catalysts for ethanol electrooxidation

Soares, Layciane Aparecida; Morais, Cláudia; Napporn, Têko W.; Kokoh, K. Boniface; Olivi, Paulo

doi:10.1016/j.jpowsour.2016.03.013

Cited by 52 publications

(41 citation statements)

References 46 publications

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“…However, in situ experiments showed that power densities obtained for fuel cells with such catalysts (max. 80 mW cm −2 at 100°C) were not higher than the state-of-the-art values and no improvements in CO 2 yields were confirmed [33][34][35][36]. In our previous work, we reported that, under certain conditions, carbon-supported platinum catalysts may show exceptionally high selectivity towards CO 2 formation, but only when current density is low [37].…”

Section: Introductionmentioning

confidence: 78%

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

2019

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Here, we report for the first time the results of systematic characterization of a low-temperature polymer electrolyte membrane direct ethanol fuel cell using DC and AC electrochemical methods. Model catalysts (carbon supported Pt nanoparticles) painted on carbon paper are used as anode and cathode. Influence of physical parameters, such as cell temperature, current density, and ethanol concentration, and anode fuel flow rate on overall cell impedance is studied. Analysis of the obtained impedance spectra in connection with DC measurements allows us to comment on cell properties and to separate different contributions to the overall cell polarization. Our results suggest that the cell impedance is dominated by anode faradaic impedance, with a small or negligible contribution from cathode faradaic impedance. The anode impedance depends strongly on current density and cell temperature, but is not significantly influenced by ethanol concentration. Presence of anode mass-transfer impedance, even when ethanol was fed to the cell in high excess, is confirmed. Based on the results, we conclude that changes in ethanol electrooxidation mechanism might manifest themselves on the impedance spectra in the low-frequency inductive loop. Nonetheless, further studies involving equivalent circuit modelling are needed to determine the exact influence of the cell parameters on the anode kinetics.

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Section: Introductionmentioning

confidence: 78%

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

2019

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“…DEFC anode catalysts have been extensively studied, but most of the work has been performed using Pt [38][39][40][41][42]. Nevertheless, it has been shown that the loading of Pt needs to be reduced by a factor of 3 to achieve an economically viable device [43].…”

Section: Introductionmentioning

confidence: 99%

Ethanol Electrooxidation at Platinum-Rare Earth (RE = Ce, Sm, Ho, Dy) Binary Alloys

et al. 2020

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Proton exchange membrane fuel cells and direct alcohol fuel cells have been extensively studied over the last three decades or so. They have emerged as potential systems to power portable applications, providing clean energy, and offering good commercial viability. Ethanol is considered one of the most interesting fuels in this field. Herein, platinum-rare earth (Pt-RE) binary alloys (RE = Ce, Sm, Ho, Dy, nominal composition 50 at.% Pt) were produced and studied as anodes for ethanol oxidation reaction (EOR) in alkaline medium. A Pt-Dy alloy with nominal composition 40 at.% Pt was also tested. Their electrocatalytic performance was evaluated by voltammetric and chronoamperometric measurements in 2 M NaOH solution with different ethanol concentrations (0.2–0.8 M) in the 25–45 °C temperature range. Several EOR kinetic parameters were determined for the Pt-RE alloys, namely the charge transfer and diffusion coefficients, and the number of exchanged electrons. Charge transfer coefficients ranging from 0.60 to 0.69 and n values as high as 0.7 were obtained for the Pt0.5Sm0.5 electrode. The EOR reaction order at the Pt-RE alloys was found to vary between 0.4 and 0.9. The Pt-RE electrodes displayed superior performance for EOR than bare Pt, with Pt0.5Sm0.5 exhibiting the highest electrocatalytic activity. The improved electrocatalytic activity in all of the evaluated Pt-RE binary alloys suggests a strategy for the solution of the existing anode issues due to the structure-sensitive EOR.

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“…6,7 However, the sluggish kinetics of ethanol oxidation reaction (EOR) and the 2 or 4 electron-pathway efficiency still remain the main obstacle for the development of this sustainable fuel cell. [10][11][12][13] Importantly, this partial oxidation of ethanol is due to the weak cleavage rate of the C-C bond through the electrochemical process at low temperature. 14,15 Thereby, acetaldehyde and acetic acid (or acetate) are the main reaction compounds obtained and oen CO 2 (or carbonate) is obtained under traces state.…”

Section: Introductionmentioning

confidence: 99%

“…24,28,29 In acid medium, this modication can be noticed in the reaction products distribution in which the concentration of acetaldehyde decreases when that of CO 2 increases, compared to the ndings at the surface of Pt alone. 12,30,31 Recently, Mukherjee et al 26 investigated the EOR in alkaline medium using Pt-Rh alloys supported on nickel. They showed that the addition of Rh promotes remarkably the reaction process, including the formation of carbonate-like nal reaction product.…”

Section: Introductionmentioning

confidence: 99%

“…11,34 Additionally, properties such as particle size, morphology and porosity also inuence directly the performance of the electrocatalyst and can be controlled by the synthesis method. 12,23 Several preparation methods of PtRh catalysts were proposed in the literature such as electrodeposition 17,35 microwave-assisted, 12 hydrothermal synthesis, 36 polyol method, 31,[37][38][39] and, borohydride-reduction method. [40][41][42][43][44] However, to avoid any limitation in activity due to the remained organic surfactants on the catalysts, a suitable synthesis approach is required.…”

Section: Introductionmentioning

confidence: 99%

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Rhodium effects on Pt anode materials in a direct alkaline ethanol fuel cell

et al. 2020

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Beneficial effects of rhodium and tin oxide on carbon supported platinum catalysts for ethanol electrooxidation

Cited by 52 publications

References 46 publications

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

Ethanol Electrooxidation at Platinum-Rare Earth (RE = Ce, Sm, Ho, Dy) Binary Alloys

Rhodium effects on Pt anode materials in a direct alkaline ethanol fuel cell

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