Electrochemical promotion (NEMCA) of CH4 and C2H4 oxidation on Pd/YSZ and investigation of the origin of NEMCA via AC impedance spectroscopy

Frantzis, A.; Bebelis, S.; Vayenas, C.G.

doi:10.1016/s0167-2738(00)00528-2

Cited by 75 publications

(28 citation statements)

References 19 publications

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“…Figure 10 shows that there is an increase in catalytic rate as a function of temperature at all applied positive current values for 400, 425 and 450 • C. It can be noticed that upon application of small current of 1 µA, a significant rate increase was detected, resulting in a logarithmic-shape relationship of rate increase versus applied current. In addition, a highest value of~2400 was found for the apparent Faradaic efficiency, constructing that a very minimal current was able to result in a change of the Pd surface oxidation state and hence the adsorption strength of methane reactant [15,16,18,20]. Table 1 compares EPOC of methane oxidation on Pd/YSZ found in this work to previous studies carried out on Pd catalyst-electrode deposited on YSZ solid-electrolyte.…”

Section: Resultssupporting

confidence: 54%

“…It can be noticed that upon application of small current of 1 μA, a significant rate increase was detected, resulting in a logarithmic-shape relationship of rate increase versus applied current. In addition, a highest value of ~2400 was found for the apparent Faradaic efficiency, constructing that a very minimal current was able to result in a change of the Pd surface oxidation state and hence the adsorption strength of methane reactant [15,16,18,20]. Similarly, the effect of temperature on closed-circuit reaction rate was tested at different galvanostatic conditions.…”

Section: Resultsmentioning

confidence: 99%

“…The electrochemical promotion of complete methane oxidation was investigated on palladium catalysts prepared using various methods as summarized in Table 1 [15][16][17][18][19][20][21][22][23]. Electrochemical promotion of Pd thick film catalyst electrode prepared using wet impregnation was investigated in the temperature range of 470-600 • C [18].…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical Promotion of Nanostructured Palladium Catalyst for Complete Methane Oxidation

2019

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Electrochemical promotion of catalysis (EPOC) was investigated for methane complete oxidation over palladium nano-structured catalysts deposited on yttria-stabilized zirconia (YSZ) solid electrolyte. The catalytic rate was evaluated at different temperatures (400, 425 and 450 °C), reactant ratios and polarization values. The electrophobic behavior of the catalyst, i.e., reaction rate increase upon anodic polarization was observed for all temperatures and gas compositions with an apparent Faradaic efficiency as high as 3000 (a current application as low as 1 μA) and maximum rate enhancement ratio up to 2.7. Temperature increase resulted in higher enhancement ratios under closed-circuit conditions. Electrochemical promotion experiments showed persistent behavior, where the catalyst remained in the promoted state upon current or potential interruption for a long period of time. An increase in the polarization time resulted in a longer-lasting persistent promotion (p-EPOC) and required more time for the reaction rate to reach its initial open-circuit value. This was attributed to continuous promotion by the stored oxygen in palladium oxide, which was formed during the anodic polarization in agreement with p-EPOC mechanism reported earlier.

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Section: Resultssupporting

confidence: 54%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrochemical Promotion of Nanostructured Palladium Catalyst for Complete Methane Oxidation

2019

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“…Rate enhancement factors Λ are low, typically less than five, due to the high operating temperatures and concomitantly high I o (exchange current of the catalyst-solid electrolyte interface) values. The CH 4 oxidation on Pd (Frantzis et al, 2000) exhibits a very pronounced NEMCA behaviour at much lower temperatures (380-440 o C) compared with those on Pt catalysts (650-750 o C). For positive overpotentials the ρ values are as high as 89, with Λ values up to 105.…”

Section: Other Light Hydrocarbon Oxidationsmentioning

confidence: 96%

Electrochemical promotion of catalysis (EPOC): Perspectives for application to gas emissions treatment

2013

Global NEST Journal

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Heterogeneous Catalysis and Electrocatalysis can be used very effectively on air pollution control. Air emissions coming either from mobile sources or from stationary sources, including volatile organic emissions, nitrogen oxides, hydrocarbons and carbon monoxide could be well converted to harmless non-pollutants at reasonable temperatures with cost-effective systems utilizing heterogeneous catalysis and suitable catalysts. Some of the disadvantages of conventional heterogeneous catalysts are the high production cost (since most of them are metal supported catalysts), the short life time (due to the catalyst deactivation) and the weakness to control their activity during the catalytic process. A new phenomenon of Solid State Electrochemistry called Electrochemical Promotion of Catalysis (EPOC) combined with classical heterogeneous catalysis could be applied in order to overcome some of the above problems. In this paper we are trying to show with characteristic examples how EPOC could be useful in environmentally important reactions (oxidations, reductions, etc). The results show that EPOC reveals great perspectives in environmental issues and especially in gas emissions treatment technology. The utilization of EPOC could be really useful since we can increase the catalytic activity, alter the selectivity to the desirable products and simultaneous control the reaction rate during a given electrocatalytic process.

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“…In this work Ψ is expressed by  and Φ, both of which are experimentally measurable (Schindler et al, 1989;Tsiplakides et al, 2007;Tsiplakides and Vayenas, 2001;Tsiplakides and Vayenas, 2002;Frantzis et al, 2000;Nowotny et al, 1989;Nowotny and Sloma, 1991). where E emf is the electromotive force ( Fig.…”

Section: Interfacial Variation Of the Volta Potentialmentioning

confidence: 99%

Lanthanum strontium vanadate in solid oxide fuel cells.

Ge¹

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Here I would like to express my most sincere appreciation and gratitude to my supervisor, Professor Chan Siew Hwa, for his considerate guidance and encouragement all throughout this PhD project. I have learnt so much for his expertise in the fields of solid oxide fuel cells and mathematical modelling. More than a supervisor, it is his personality, lifestyle, and working philosophy that inspire me all through this four-year odyssey. I thank Dr. Liu Qinglin for his initial effort on launching this PhD project. I also thank Mr. Chen Xinbing, Mr. Alireza Babaei, and Dr. Zhang Lan for miscellaneous discussions. Mr. Zhao Cunlu is acknowledged for introducing me the computational tool, Wolfram Mathematica ® 7. Ms. Fang Yanan (School of MSE) is acknowledged for her kindly help in X-ray powder diffraction characterization. My warmest acknowledgement goes to Dr. Fu Changjing for insightful discussions over versatile project topics. My thanks also extend to all technicians in Fuel Cell Laboratory (ERI@N), Materials Laboratory A, and Computer Aided Engineering Laboratory for technical guidance and assistance.

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Electrochemical promotion (NEMCA) of CH4 and C2H4 oxidation on Pd/YSZ and investigation of the origin of NEMCA via AC impedance spectroscopy

Cited by 75 publications

References 19 publications

Electrochemical Promotion of Nanostructured Palladium Catalyst for Complete Methane Oxidation

Electrochemical Promotion of Nanostructured Palladium Catalyst for Complete Methane Oxidation

Electrochemical promotion of catalysis (EPOC): Perspectives for application to gas emissions treatment

Lanthanum strontium vanadate in solid oxide fuel cells.

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