Efficient C–C bond splitting on Pt monolayer and sub-monolayer catalysts during ethanol electro-oxidation: Pt layer strain and morphology effects

Loukrakpam, Rameshwori; Yuan, Qingshan; Petkov, Valeri; Gan, Lin; Rudi, Stefan; Yang, Ruizhi; Huang, Yunhui; Brankovic, Stanko R.; Strasser, Peter

doi:10.1039/c4cp02791d

Cited by 51 publications

(50 citation statements)

References 24 publications

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“…The mass current density of forward peak on Pt 53 Cu 47 performance. The electrocatalytic activity of Pt 53 Cu 47 was also comparable to the state-of-the-art Pt-alloy catalysts reported by Strasser's group, which may be attributed to the stain effects induced by the voltammetric surface dealloying treatment [46,47]. Fig.…”

Section: Resultssupporting

confidence: 63%

Three-dimensional hierarchical porous platinum–copper alloy networks with enhanced catalytic activity towards methanol and ethanol electro-oxidation

Fan

Liu

ZongWen

et al. 2015

Journal of Power Sources

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Section: Resultssupporting

confidence: 63%

Three-dimensional hierarchical porous platinum–copper alloy networks with enhanced catalytic activity towards methanol and ethanol electro-oxidation

Fan

Liu

ZongWen

et al. 2015

Journal of Power Sources

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“…This result is unequivocal and is in line with previous reports. 24,[28][29][30][31] Now, comparing the current densities, the scenario is more complex and different methods provide conflicting results. By using the ECSA, the current density produced on Pt/C is higher than that on Pt 4 Ru 5 Sn 1 /C (Figure 1a).…”

Section: Resultsmentioning

confidence: 99%

“…Membrane-electrode assemblies (MEAs) were made following a previous work. 29 Namely, anode and cathode were hot pressed onto the Nafion 115 membrane at 125 °C under a pressure of 50 MPa for 2 min. Experiments were carried out in single cells of 5 cm 2 of active geometric area at operation temperature of 70 o C. MEAs were kept wet using humidification bottles at 85 and 75 °C, respectively.…”

Section: Fuel Cell Experimentsmentioning

confidence: 99%

Estimating the Time-Dependent Performance of Nanocatalysts in Fuel Cells Based on a Cost-Normalization Approach

Zanata¹,

Fernández²,

Santos³

et al. 2016

Journal of the Brazilian Chemical Society

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Researchers have developed new catalysts for fuel cells (FC), whose performances are compared after applying different normalization procedures. However, there is not a standard procedure. The current produced from CO electrooxidation was compared for Pt 4 Ru 5 Sn 1 /C and homemade Pt/C nanoparticles (NPs) normalized by different methods and the use of different methods renders different interpretations. Since the whole field aims to maximize the cost-effectiveness, a complementary method to normalize currents and power in terms of the total cost of the nanocatalyst, the Catalyst-based Cost method (CbC), was proposed. CbC considers the cost of all metals employed to build the catalyst, not only those ones with available surfaces. By applying a simple smoothing method on the prices in a time series, we were able to forecast the prices and consequently the power density of a FC. CbC provides tools for industrials forecast the designing of nanomaterials with improved efficiency and low cost.Keywords: fuel cell, catalyst, normalization of current and power, cost of metal, forecasting activity IntroductionThe continuous growth of the energy demand opened a wide field of research for energy converters, among which fuel cells have been exhaustively studied. Fuel cells can produce energy with low environmental impact since they generate power by the oxidation of a fuel at the anode and reduction of O 2 at the cathode. Fuel cells can be fed by H 2 or small alcohols, as methanol and ethanol. The catalysts, both anodes and cathodes, are mainly based on Pt, which is historically an expensive material.1 This is the main reason why many efforts have been made to replace Pt (at least partially) in catalysts used in fuel cells.When a new nanoparticle catalyst is produced, the normalization of the electrochemical current generated by its use is imperative in electrocatalysis, since this procedure allows distinct surfaces to be directly compared for a given reaction in terms of their intrinsic electroactivities. In this context, different normalization methods generate multiple interpretations about the activity of a catalyst. This lack of consensus hinders the comparison of different materials in terms of their electrochemical performances and generates impasses that prevent a faster development of the research area.A method commonly used consists in normalizing the currents by the electrochemically active surface area (ECSA), which is highly useful but not easily accessed for many materials. For Pt-based catalysts (as PtRu/C Zanata et al. 1981 Vol. 27, No. 11, 2016 and PtRuSn/C) the ECSA is sometimes estimated by the charge involved in the H desorption region.2-5 For Pd-based catalysts, the ECSA is usually calculated by the charge involved in the reduction of a PdO monolayer. [6][7][8] The main concern about using the ECSA for multi-metallic catalysts calculated by these methods lies on the fact that the metal lattice parameter suffers intense modifications when an additional element is inserted into its structure. 9,10 In t...

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“…[11][12][13][14][15][16] On the other hand, the morphology of P deposit is a direct function of SLRR reaction kinetics and stoichiometry. 12,17 They are dependent on experimental conditions.…”

Section: Deposition Via Surface Limited Redox Replacement (Slrr) Of Umentioning

confidence: 99%

Editors' Choice—Reaction Kinetics of Metal Deposition via Surface Limited Redox Replacement of Underpotentially Deposited Monolayer Studied by Surface Reflectivity and Open Circuit Potential Measurements

Bulut

Dole

et al. 2017

J. Electrochem. Soc.

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Presented work studies the relation between kinetics of metal deposition via surface limited redox replacement (SLRR) of underpotentially deposited (UPD) monolayer (ML) and experimental parameters of reaction solution such as meal ions concentrations and supporting electrolyte concentration. The model system is Au deposition on Au(111) via SLRR of Pb UPD ML. The rate constant of the SLRR reaction for different solution designs is determined from temporal change of electrode surface reflectivity and from the open circuit potential transients' analysis. The obtained results show clearly that reaction kinetics of metal deposition via SLRR of UPD ML is significantly affected by the design of the reaction solution i.e. the UPD metal ion, depositing metal ion, and supporting electrolyte concentrations. The ten-fold change of concentration of either solution parameter produces approximately the same change in the value of the rate constants. The presented results have fundamental importance for the future development and application of the metal deposition via SLRR of UPD ML. They offer a link between the reaction solution design and expected trend in SLRR reaction rate, which transposes to successful control of deposition flux, nucleation density and resulting morphology of the deposit. Deposition via Surface Limited Redox Replacement (SLRR) of underpotentially deposited (UPD) monolayer (ML)1 has gained a lot of attention and applications in last two decades.2-4 The main idea is to use an UPD ML as sacrificial material to reduce/deposit a more noble metal (SLRR reaction i.e. galvanic displacement). The basic stoichiometry of the SLRR reaction and deposition process is shown by Equation 1.Here, M and P and S(h,k,l) stand for UPD metal/ion, depositing metal/ion and substrate, while m + /m and p + /p represent the oxidation state of M and P metal ions and corresponding stoichiometry coefficients. Over the years, several experimental protocols for deposition via SLRR of UPD ML have been developed. The first and the basic one, 1,6 involves formation of the UPD ML of M on the substrate S(h,k,l), (potential controlled step) and then subsequent immersion of M UPD /S(h,k,l) into a separate reaction solution where SLRR occurs and deposition of P takes place at open circuit (sample shuffling approach). The second protocol involves the stagnant substrate but sequential application of potential control in solution for UPD ML formation and then application of solution for SLRR reaction and deposition of P at open circuit (solution shuffling approach 7 ). The most recent development has introduced a "one-solution, one-cell" experimental design. 8,9 In this case, the same solution serves for UPD ML formation and subsequent SLRR reaction at open circuit potential. This protocol assumes a sequence of potential controlled step, where co-deposition of UPD ML of M with small amount of P occurs, and the open circuit step, where SLRR reaction and deposition of P proceeds. The very details of these three protocols and their applications hav...

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Efficient C–C bond splitting on Pt monolayer and sub-monolayer catalysts during ethanol electro-oxidation: Pt layer strain and morphology effects

Cited by 51 publications

References 24 publications

Three-dimensional hierarchical porous platinum–copper alloy networks with enhanced catalytic activity towards methanol and ethanol electro-oxidation

Three-dimensional hierarchical porous platinum–copper alloy networks with enhanced catalytic activity towards methanol and ethanol electro-oxidation

Estimating the Time-Dependent Performance of Nanocatalysts in Fuel Cells Based on a Cost-Normalization Approach

Editors' Choice—Reaction Kinetics of Metal Deposition via Surface Limited Redox Replacement of Underpotentially Deposited Monolayer Studied by Surface Reflectivity and Open Circuit Potential Measurements

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