Reduction of CO2 under high pressure and high temperature on Pb-granule electrodes in a fixed-bed reactor in aqueous medium

Köleli, Fatih; Balun, Didem

doi:10.1016/j.apcata.2004.07.006

Cited by 105 publications

(56 citation statements)

References 36 publications

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“…The effect of pressure is relatively straightforward. Though some sources indicate that the reaction rate is nearly independent of CO 2 pressure [6] most who have studied this variable (up to 6000 kPa(abs)) show a strong positive effect of CO 2 pressure on the cathode potential and the partial current density for reaction 1, consistent with a reaction order of about one with respect to CO 2 concentration in the catholyte [12,14,21]. The effect of temperature is more problematic.…”

Section: Introductionmentioning

confidence: 83%

“…Table 1 presents a summary of some representative results from such work published since 1970 [5][6][7][8][9][10][11][12][13][14][15][16]. As indicated in Table 1 all (published) work prior to 2004 was done in laboratory scale batch reactors [17] operating at currents from a few mA up to about 2 A.…”

Section: Introductionmentioning

confidence: 99%

“…Me cathode material P CO 2 pressure (Bar(abs) or kPa(abs)) P cathode cathode side pressure (kPa (abs)) T temperature (K) t operating time (h) X 1 , X 2 , X 3 factorial variables defined in Tables 6,9,10,13,14,16 and 17 y volume fraction (i.e. mole fraction) in gas phase (dimensionless) s thickness of 3D cathode (m)…”

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confidence: 99%

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Development of a continuous reactor for the electro-reduction of carbon dioxide to formate – Part 1: Process variables

Oloman

2006

J Appl Electrochem

114

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This paper reports an experimental investigation into the effects of five process variables on the performance of a bench-scale continuous electrochemical reactor used in the reduction of CO 2 to potassium formate, and interprets the data in terms of reactor engineering for a (speculative) industrial process for electro-reduction of CO 2 . The process variables: temperature, catholyte species, catholyte conductivity, cathode specific surface area and cathode thickness were studied, along with CO 2 pressure and current density, in a set of factorial and parametric experiments aimed to unravel their main effects and interactions. These variables showed complex interdependent effects on the reactor performance, as measured by the current efficiency and specific energy for generation of formate (HCO 2 ) ). The ''best'' result has a formate current efficiency of 86% at a superficial current density of 1.3 kA m )2 , with a product solution of 0.08 M KHCO 2 and specific electrochemical energy of 260 kWh per kmole formate. The combined results indicate good prospects for process optimization that could lead to development of an industrial scale reactor. NomenclatureC catholyte composition CE current efficiency (dimensionless) E cathode potential (VSHE) E cell full-cell operating voltage (absolute value) (V) E o Standard equilibrium electrode potential (VSHE) GDE gas diffusion electrode i geometric (superficial) current density (kA m )2 ) i max maximum geometric (superficial) current density (kA m )2 )Me cathode material P CO 2 pressure (Bar(abs) or kPa(abs)) P cathode cathode side pressure (kPa (abs)) T temperature (K) t operating time (h) X 1 , X 2 , X 3 factorial variables defined in Tables 6, 9, 10, 13, 14, 16 and 17 y volume fraction (i.e. mole fraction) in gas phase (dimensionless) s thickness of 3D cathode (m)

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Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

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Development of a continuous reactor for the electro-reduction of carbon dioxide to formate – Part 1: Process variables

Oloman

2006

J Appl Electrochem

114

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“…For instance CO 2 solubility is known to be better in methanol than in water, particularly at low temperatures (8-15 times at 273 K) [14,16,24]. However, the conversion of CO 2 on Pb or Cu electrodes, even if leading to the formation of formic acid, also produces other organic molecules, decreasing the selectivity and complicating the separation of end products [9,17,[32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 96%

Electro-reduction of carbon dioxide to formate on lead electrode in aqueous medium

et al. 2008

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The electrochemical reduction of carbon dioxide on a lead electrode was studied in aqueous medium. Preliminary investigations carried out by cyclic voltammetry were used to determine the optimized conditions of electrolysis. They revealed that the CO 2 reduction process was enhanced at a pH value of 8.6 for the cathodic solution i.e. when the predominant form of CO 2 was hydrogenocarbonate ion. Long-term electrolysis was carried out using both potentiometry and amperometry methods in a filterpress cell in which the two compartments were separated by a cation-exchange membrane (Nafion Ò 423). Formate was detected and quantified by chromatography as the exclusive organic compound produced with a high Faradaic yield (from 65% to 90%). This study also revealed that the operating temperature played a key role in the hydrogenation reaction of carbon dioxide into formate in aqueous medium.

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“…The value of 0.121 V dec −1 is typical for a one electron transfer reaction for H ad formation. 34,35 Moreover, the calculated α -value (transfer coefficient) of ca. 0.49 confirms a one electron step for H ad formation.…”

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confidence: 99%

Dinitrogen reduction on a polypyrrole coated Pt electrode under high-pressure conditions: electrochemical impedance spectroscopy studies

Kayan

Köleli²

2015

Turk J Chem

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Abstract:The electrochemical impedance spectroscopy (EIS) responses of a polypyrrole (PPy)-coated platinum electrode were investigated during N 2 -reduction to ammonia in aqueous medium. Kinetic parameters such as film resistance, pore resistance, and double layer capacitance were analyzed as a function of applied potential and polymer film thickness.The relation between kinetic parameters was discussed by combining electrolysis results. It was found that the optimum film thickness of polypyrrole was 0.73 µ m and optimum potential for ammonia synthesis was -0.150 V under 60 bar α -transfer coefficient of 0.49 and an exchange current density with a value of 3.17 10 −3 A cm −2 were characteristic for H ad formation in acidic aqueous medium.

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Reduction of CO2 under high pressure and high temperature on Pb-granule electrodes in a fixed-bed reactor in aqueous medium

Cited by 105 publications

References 36 publications

Development of a continuous reactor for the electro-reduction of carbon dioxide to formate – Part 1: Process variables

Development of a continuous reactor for the electro-reduction of carbon dioxide to formate – Part 1: Process variables

Electro-reduction of carbon dioxide to formate on lead electrode in aqueous medium

Dinitrogen reduction on a polypyrrole coated Pt electrode under high-pressure conditions: electrochemical impedance spectroscopy studies

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