scholarly journals Low-Temperature Electrocatalytic Conversion of CO2 to Liquid Fuels: Effect of the Cu Particle Size

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 340 ◽  
Author(s):  
Antonio de Lucas-Consuegra ◽  
Juan Serrano-Ruiz ◽  
Nuria Gutiérrez-Guerra ◽  
José Valverde
Keyword(s):  
Particle Size ◽  
Low Temperature ◽  
Gas Phase ◽  
Electrocatalytic Activity ◽  
Water Electrolysis ◽  
Proton Exchange ◽  
Liquid Fuels ◽  
Main Reaction ◽  
Membrane Electrode ◽  
Reaction Products

A novel gas-phase electrocatalytic system based on a low-temperature proton exchange membrane (Sterion) was developed for the gas-phase electrocatalytic conversion of CO2 to liquid fuels. This system achieved gas-phase electrocatalytic reduction of CO2 at low temperatures (below 90 °C) over a Cu cathode by using water electrolysis-derived protons generated in-situ on an IrO2 anode. Three Cu-based cathodes with varying metal particle sizes were prepared by supporting this metal on an activated carbon at three loadings (50, 20, and 10 wt %; 50% Cu-AC, 20% Cu-AC, and 10% Cu-AC, respectively). The cathodes were characterized by N2 adsorption–desorption, temperature-programmed reduction (TPR), and X-ray diffraction (XRD) and their performance towards the electrocatalytic conversion of CO2 was subsequently studied. The membrane electrode assembly (MEA) containing the cathode with the largest Cu particle size (50% Cu-AC, 40 nm) showed the highest CO2 electrocatalytic activity per mole of Cu, with methyl formate being the main product. This higher electrocatalytic activity was attributed to the lower Cu–CO bonding strength over large Cu particles. Different product distributions were obtained over 20% Cu-AC and 10% Cu-AC, with acetaldehyde and methanol being the main reaction products, respectively. The CO2 consumption rate increased with the applied current and reaction temperature.

scholarly journals Low-temperature electrocatalytic conversion of CO2 to liquid fuels: effect of the Cu particle size

2018 ◽  
Author(s):  
Antonio De Lucas-Consuegra ◽  
Juan Carlos Serrano-Ruiz ◽  
Nuria Gutierrez-Guerra ◽  
José Luis Valverde
Keyword(s):  
Particle Size ◽  
Low Temperature ◽  
Gas Phase ◽  
Electrocatalytic Activity ◽  
Water Electrolysis ◽  
Proton Exchange ◽  
Liquid Fuels ◽  
Main Reaction ◽  
Membrane Electrode ◽  
Reaction Products

A novel gas-phase electrocatalytic system based on a low-temperature proton exchange membrane (Sterion) was developed for the gas phase electrocatalytic conversion of CO2 to liquid fuels. This system achieved gas-phase electrocatalytic reduction of CO2 at low temperatures (below 90 ºC) over a Cu cathode by using water electrolysis-derived protons generated in-situ on an IrO2 anode. Three Cu-based cathodes with varying metal particle sizes were prepared by supporting this metal on an activated carbon at three loadings (50, 20, and 10 wt%; 50%Cu-AC, 20%Cu-AC, and 10%Cu-AC, respectively). The cathodes were characterized by N2 adsorption–desorption, temperature-programmed reduction (TPR), and X-ray diffraction (XRD) whereas their performance towards the electrocatalytic conversion of CO2 was subsequently studied. The membrane electrode assembly (MEA) containing the cathode with the largest Cu particle size (50%Cu-AC, 40 nm) showed the highest CO2 electrocatalytic activity per mole of Cu, with methyl formate being the main product. This higher electrocatalytic activity was attributed to the lower Cu–CO bonding strength over large Cu particles. Different product distributions were obtained over 20%Cu-AC and 10%Cu-AC, with acetaldehyde and methanol being the main reaction products, respectively. The CO2 consumption rate increased with the applied current and the reaction temperature.

scholarly journals On the Effect of Anion Exchange Ionomer Binders in Bipolar Electrode Membrane Interface Water Electrolysis

2021 ◽  
Author(s):  
Britta Mayerhöfer ◽  
Konrad Ehelebe ◽  
Florian Dominik Speck ◽  
Markus Bierling ◽  
Johannes Bender ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Water Electrolysis ◽  
Membrane Electrode Assembly ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Bipolar Electrode ◽  
Electrode Interface ◽  
Exchange Membrane ◽  
Electrode Membrane ◽  
Pem Water Electrolyzer

Bipolar membrane|electrode interface water electrolyzers (BPEMWE) were found to outperform a proton exchange membrane (PEM) water electrolyzer reference in a similar membrane electrode assembly (MEA) design based on individual porous...

Perchlorosilanes and Perchlorocarbosilanes as Precursors to Silicon Carbide

2006 ◽  
Vol 911 ◽  
Author(s):  
Vladimir Sevastyanov ◽  
Yurij Ezhov ◽  
Roman Pavelko ◽  
Nikolaj Kuznetsov
Keyword(s):  
Thermal Decomposition ◽  
Silicon Carbide ◽  
Low Temperature ◽  
Gas Phase ◽  
Thermodynamic Modeling ◽  
Reaction System ◽  
Reaction Products ◽  
Gaseous Species ◽  
Phase Synthesis ◽  
Key Features

AbstractHomologues with the general stoichiometry a(SiCl4) : bSi : cC : d(SiC) are shown to be potential precursors for the low-temperature gas-phase synthesis of silicon carbide. Thermal decomposition of these precursors yields the chemically stable gaseous species SiCl4 and condensed Si, C, SiC, SiC+Si, or SiC+C. Thermodynamic modeling of the thermal decomposition of octachlorotrisilane, Si3Cl8, is used to analyze the key features of the thermolysis of perchlorosilanes with the general stoichiometry a(SiCl4) : bSi. The equilibrium compositions of reaction products in the Si3Cl8+CO system are determined. This reaction system enables low-temperature (400 – 1200 K) synthesis of silicon carbide.

Hydrogenolysis of Glycerol in Gas Phase on Cu-Cr Mixed Oxide Catalyst Doped with Ni

2017 ◽  
Vol 68 (5) ◽  
pp. 1118-1121
Author(s):  
Vasile Georgescu ◽  
Casen Panaitescu ◽  
Mihaela Bombos ◽  
Dorin Bombos
Keyword(s):  
Gas Phase ◽  
Propylene Glycol ◽  
Mixed Oxide ◽  
Oxide Catalyst ◽  
Molar Ratio ◽  
Main Reaction ◽  
Reaction Products ◽  
Glycerol Conversion ◽  
Mixed Oxide Catalyst ◽  
Temperature And Pressure

Hydrogenolysis of glycerol was conducted on catalyst of the type mixed oxide of Cu-Cr doped with NiO on g-Al2O3. The prepared catalyst was analyzed by XRD, IR and TPR. Catalytic tests were carried out on a laboratory plant in continuous flow system on a reactor equipped with heating mantle, at molar ratio of glycerol / hydrogen of 1/300, glycerol volume hourly space velocities 1000s-1, temperatures 200-220oC and pressures 3-5 bar. The main reaction products identified were propylene glycol and hydroxyacetone. Glycerol conversion increases with temperature and pressure on ranges of parameters studied. Selectivity to propylene glycol increases with increasing of temperature and pressure and the selectivity to hydroxyacetone decreases with increasing of temperature and pressure on the variation range of the parameters studied.

Comparison of Performance Losses Between Ultrasonic and Thermal Bonding of Membrane Electrode Assemblies in Proton Exchange Membrane Fuel Cells

2013 ◽  
Vol 10 (4) ◽  
Author(s):  
Joseph Beck ◽  
Daniel Walczyk ◽  
Steve Buelte ◽  
Casey Hoffman
Keyword(s):  
Low Temperature ◽  
Process Analysis ◽  
Bonding Process ◽  
Proton Exchange ◽  
Sensitivity Analyses ◽  
Pure Oxygen ◽  
Catalyst Loading ◽  
Membrane Electrode ◽  
Ultrasonic Bonding ◽  
Current Densities

Ultrasonic bonding of low-temperature PEM membrane electrode assembly (MEA) components together has been shown previously to cut both cycle time and energy input of that manufacturing step by over an order of magnitude as compared to the industry standard of thermal pressing. This paper compares performance between ultrasonically and thermally bonded low-temperature MEAs and characterizes the performance losses from the new bonding process. A randomized, full factorial experiment was designed and conducted to examine performance of MEAs with 10 cm2 active area while varying three factors: bonding method (ultrasonically and thermally pressed using previously optimized bonding parameters), membrane condition (dry and conditioned Nafion® 115), and electrode catalyst loading (0.16 and 0.33 mg Pt/cm2). Ultrasonic MEAs performed as well as their thermal MEAs across all tested current densities with pure oxygen supplied to the cathode. However, thermal MEAs outperformed ultrasonic MEAs at current densities above 0.4 A/cm2 with air supplied to the cathode. Impedance spectroscopy, cyclic voltammetry, and flow sensitivity analyses were used to characterize the performance losses of the ultrasonic MEAs. The data suggest the presence of oxygen diffusion losses above 0.4 A/cm2 when air was supplied to the cathode. Ultrasonic MEAs were three times more sensitive to changes in air flow rate on the cathode than the thermally MEAs. Increasing the platinum catalyst loading from 0.16 to 0.33 mg Pt/cm2 resulted in a performance enhancement of approximately 20 mV and 65% greater electrochemical surface area. Understanding the effect of ultrasonic bonding on various performance losses will help optimize the MEA bonding process. Analysis of specific losses present for ultrasonic MEAs may also provide insight into the design of MEA components for ultrasonic bonding.

scholarly journals Directly coated membrane electrode assemblies for proton exchange membrane water electrolysis

2020 ◽  
Vol 110 ◽  
pp. 106640 ◽  
Author(s):  
Peter Holzapfel ◽  
Melanie Bühler ◽  
Chuyen Van Pham ◽  
Friedemann Hegge ◽  
Thomas Böhm ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Water Electrolysis ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Membrane Electrode Assemblies ◽  
Electrode Assemblies ◽  
Exchange Membrane ◽  
Coated Membrane

scholarly journals Innovative Membrane Electrode Assembly (MEA) Fabrication for Proton Exchange Membrane Water Electrolysis

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4218 ◽  
Author(s):  
Guo-Bin Jung ◽  
Shih-Hung Chan ◽  
Chun-Ju Lai ◽  
Chia-Chen Yeh ◽  
Jyun-Wei Yu
Keyword(s):  
Proton Exchange Membrane ◽  
Water Electrolysis ◽  
Membrane Electrode Assembly ◽  
Proton Exchange ◽  
Ozone Production ◽  
Membrane Electrode ◽  
Coating Method ◽  
Exchange Membrane ◽  
Catalyst Utilization ◽  
Labor Consuming

In order to increase the hydrogen production rate as well as ozone production at the anode side, increased voltage application and more catalyst utilization are necessary. The membrane electrode assembly (MEA) produces hydrogen/ozone via proton exchange membrane water electrolysis (PEMWE)s which gives priority to a coating method (abbreviation: ML). However, coating takes more effort and is labor-consuming. This study will present an innovative preparation method, known as flat layer (FL), and compare it with ML. FL can significantly reduce efforts and largely improve MEA production. Additionally, MEA with the FL method is potentially durable compared to ML.

scholarly journals Atmospheric degradation of 3-methylfuran: kinetic and products study

2011 ◽  
Vol 11 (7) ◽  
pp. 3227-3241 ◽  
Author(s):  
A. Tapia ◽  
F. Villanueva ◽  
M. S. Salgado ◽  
B. Cabañas ◽  
E. Martínez ◽  
...  
Keyword(s):  
Gas Phase ◽  
Aromatic Ring ◽  
Atmospheric Pressure ◽  
Ring Opening ◽  
Room Temperature ◽  
Rate Coefficients ◽  
Main Reaction ◽  
Phase Reaction ◽  
Reaction Products ◽  
Cl Atoms

Abstract. A study of the kinetics and products obtained from the reactions of 3-methylfuran with the main atmospheric oxidants has been performed. The rate coefficients for the gas-phase reaction of 3-methylfuran with OH and NO3 radicals have been determined at room temperature and atmospheric pressure (air and N2 as bath gases), using a relative method with different experimental techniques. The rate coefficients obtained for these reactions were (in units cm3 molecule−1 s−1) kOH = (1.13 ± 0.22) × 10−10 and kNO3 = (1.26 ± 0.18) × 10−11. Products from the reaction of 3-methylfuran with OH, NO3 and Cl atoms in the absence and in the presence of NO have also been determined. The main reaction products obtained were chlorinated methylfuranones and hydroxy-methylfuranones in the reaction of 3-methylfuran with Cl atoms, 2-methylbutenedial, 3-methyl-2,5-furanodione and hydroxy-methylfuranones in the reaction of 3-methylfuran with OH and NO3 radicals and also nitrated compounds in the reaction with NO3 radicals. The results indicate that, in all cases, the main reaction path is the addition to the double bond of the aromatic ring followed by ring opening in the case of OH and NO3 radicals. The formation of 3-furaldehyde and hydroxy-methylfuranones (in the reactions of 3-methylfuran with Cl atoms and NO3 radicals) confirmed the H-atom abstraction from the methyl group and from the aromatic ring, respectively. This study represents the first product determination for Cl atoms and NO3 radicals in reactions with 3-methylfuran. The reaction mechanisms and atmospheric implications of the reactions under consideration are also discussed.

The gas-phase reaction of the CF3 radical with thiophene

2003 ◽  
Vol 81 (12) ◽  
pp. 1477-1481 ◽  
Author(s):  
Olga S Herrera ◽  
Jorge D Nieto ◽  
Silvia I Lane ◽  
Elena V Oexler
Keyword(s):  
Reaction Mechanism ◽  
Gas Phase ◽  
Radical Reaction ◽  
Main Reaction ◽  
Phase Reaction ◽  
Reaction Products ◽  
Isomeric Mixture ◽  
Gas Phase Reaction ◽  
Plausible Mechanism ◽  
Cf3 Radical

The reaction of CF3 radicals, generated by photolysis of CF3I or hexafluoroacetone with thiophene, was studied in the gas phase at 25 °C. At conversion of thiophene less than 20%, monosubstituted CF3-thiophenes were found as the main reaction products, in addition to CF3H, C2F6, and monosubstituted dihydro-CF3-thiophene, the latter in very low proportion. An isomeric mixture of 2- and 3-CF3-thiophene was obtained in a ratio of about 16, independent of the radical source used (CF3I or hexafluoroacetone) to produce the CF3 radicals. A plausible mechanism that accounts for the observed products is proposed, and the reactivity of thiophene toward the CF3 radical at 25 °C was determined as kadd/kc1/2 = 106 ± 4 cm3/2 mol–1/2 s–1/2.Key words: thiophene, trifluoromethyl radical, reaction mechanism, reactivity.

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