Hydrogen diffusion in proton conducting oxides and in nanocrystalline metals

2007 ◽  
pp. 247-252 ◽  
Author(s):  
R. Hempelmann
Keyword(s):  
Hydrogen Diffusion ◽  
Nanocrystalline Metals ◽  
Proton Conducting ◽  
Conducting Oxides

Interaction of H2O, O2 and H2 with Proton Conducting Oxides Based on Lanthanum Scandates

2019 ◽  
pp. 88-100
Author(s):  
A. S. Farlenkov ◽  
N. A. Zhuravlev ◽  
Т. A. Denisova ◽  
М. V. Ananyev
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Phase ◽  
Molecular Hydrogen ◽  
Proton Magnetic Resonance ◽  
Partial Pressure Of Oxygen ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Temperature Range ◽  
Apparent Level

The research uses the method of high-temperature thermogravimetric analysis to study the processes of interaction of the gas phase in the temperature range 300–950 °C in the partial pressure ranges of oxygen 8.1–50.7 kPa, water 6.1–24.3 kPa and hydrogen 4.1 kPa with La1–xSrxScO3–α oxides (x = 0; 0.04; 0.09). In the case of an increase in the partial pressure of water vapor at a constant partial pressure of oxygen (or hydrogen) in the gas phase, the apparent level of saturation of protons is shown to increase. An increase in the apparent level of saturation of protons of the sample also occurs with an increase in the partial pressure of oxygen at a constant partial pressure of water vapor in the gas phase. The paper discusses the causes of the observed processes. The research uses the hydrogen isotope exchange method with the equilibration of the isotope composition of the gas phase to study the incorporation of hydrogen into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates. The concentrations of protons and deuterons were determined in the temperature range of 300–800 °C and a hydrogen pressure of 0.2 kPa for La0.91Sr0.09ScO3–α oxide. The paper discusses the role of oxygen vacancies in the process of incorporation of protons and deuterons from the atmosphere of molecular hydrogen into the structure of the proton conducting oxides La1–xSrxScO3–α (x = 0; 0.04; 0.09). The proton magnetic resonance method was used to study the local structure in the temperature range 23–110 °C at a rotation speed of 10 kHz (MAS) for La0.96Sr0.04ScO3–α oxide after thermogravimetric measurements in an atmosphere containing water vapor, and after exposures in molecular hydrogen atmosphere. The existence of proton defects incorporated into the volume of the investigated proton oxide from both the atmosphere containing water and the atmosphere containing molecular hydrogen is unambiguously shown. The paper considers the effect of the contributions of the volume and surface of La0.96Sr0.04ScO3–α oxide on the shape of the proton magnetic resonance spectra.

scholarly journals Direct-Hydrocarbon Proton-Conducting Solid Oxide Fuel Cells

2021 ◽  
Vol 13 (9) ◽  
pp. 4736
Author(s):  
Fan Liu ◽  
Chuancheng Duan
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Sulfur Poisoning ◽  
Oxide Fuel ◽  
Power Sources ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Operating Temperatures ◽  
Ion Conducting

Solid oxide fuel cells (SOFCs) are promising and rugged solid-state power sources that can directly and electrochemically convert the chemical energy into electric power. Direct-hydrocarbon SOFCs eliminate the external reformers; thus, the system is significantly simplified and the capital cost is reduced. SOFCs comprise the cathode, electrolyte, and anode, of which the anode is of paramount importance as its catalytic activity and chemical stability are key to direct-hydrocarbon SOFCs. The conventional SOFC anode is composed of a Ni-based metallic phase that conducts electrons, and an oxygen-ion conducting oxide, such as yttria-stabilized zirconia (YSZ), which exhibits an ionic conductivity of 10−3–10−2 S cm−1 at 700 °C. Although YSZ-based SOFCs are being commercialized, YSZ-Ni anodes are still suffering from carbon deposition (coking) and sulfur poisoning, ensuing performance degradation. Furthermore, the high operating temperatures (>700 °C) also pose challenges to the system compatibility, leading to poor long-term durability. To reduce operating temperatures of SOFCs, intermediate-temperature proton-conducting SOFCs (P-SOFCs) are being developed as alternatives, which give rise to superior power densities, coking and sulfur tolerance, and durability. Due to these advances, there are growing efforts to implement proton-conducting oxides to improve durability of direct-hydrocarbon SOFCs. However, so far, there is no review article that focuses on direct-hydrocarbon P-SOFCs. This concise review aims to first introduce the fundamentals of direct-hydrocarbon P-SOFCs and unique surface properties of proton-conducting oxides, then summarize the most up-to-date achievements as well as current challenges of P-SOFCs. Finally, strategies to overcome those challenges are suggested to advance the development of direct-hydrocarbon SOFCs.

Proton-conducting oxides for energy conversion and storage

2020 ◽  
Vol 7 (1) ◽  
pp. 011314 ◽  
Author(s):  
Chuancheng Duan ◽  
Jake Huang ◽  
Neal Sullivan ◽  
Ryan O'Hayre
Keyword(s):  
Energy Conversion ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Energy Conversion And Storage ◽  
And Storage

scholarly journals Hydrogen diffusion in high temperature proton conducting ceramics

2008 ◽  
Vol 266 (8) ◽  
pp. 1430-1433 ◽  
Author(s):  
S. Sorieul ◽  
S. Miro ◽  
M. Taillades-Jacquin ◽  
J. Dailly ◽  
F. Mauvy ◽  
...  
Keyword(s):  
High Temperature ◽  
Hydrogen Diffusion ◽  
Proton Conducting

Transport properties and stability of cobalt doped proton conducting oxides

2009 ◽  
Vol 180 (2-3) ◽  
pp. 160-167 ◽  
Author(s):  
Maria A. Azimova ◽  
Steven McIntosh
Keyword(s):  
Transport Properties ◽  
Proton Conducting ◽  
Conducting Oxides

Proton Conductivity of Compositionally Graded Proton Conducting Oxides

2003 ◽  
Vol 423-425 ◽  
pp. 441-444
Author(s):  
S. Yamaguchi ◽  
Takaaki Shishido ◽  
Mamoru Omori ◽  
A. Okubo ◽  
Satoru Yamamoto
Keyword(s):  
Proton Conductivity ◽  
Proton Conducting ◽  
Conducting Oxides

Mixed-Conducting Membranes for Hydrogen Production and Separation

2006 ◽  
Vol 972 ◽  
Author(s):  
U. Balachandran ◽  
Beihai Ma ◽  
Tae H Lee ◽  
Sun-Ju Song ◽  
Ling Chen ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Hydrogen Permeability ◽  
Composite Membranes ◽  
Ceramic Membranes ◽  
Electronic Charge ◽  
Membrane Thickness ◽  
Pure Hydrogen ◽  
Metal Composite ◽  
Proton Conducting ◽  
Conducting Oxides

AbstractMixed-conducting oxides, possessing both ionic and electronic charge carriers, have found wide application in recent years in solid-state electrochemical devices that operate at high temperatures, e.g., solid-oxide fuel cells, batteries, and sensors. These materials also hold promise as dense ceramic membranes that separate gases such as oxygen and hydrogen from mixed-gas streams. We are developing Sr-Fe-Co oxide (SFC) as a membrane that selectively transports oxygen during partial oxidation of methane to syngas (mixture of CO and H2) because of SFC's high combined electronic and ionic conductivities. We have evaluated extruded tubes of SFC for conversion of methane to syngas in a reactor that was operated at ≈900°C. Methane conversion efficiencies were >90%, and some of the reactor tubes were operated for >1000 h. We are also developing dense proton-conducting oxides to separate pure hydrogen from product streams that are generated during methane reforming and coal gasification. Hydrogen selectivity in these membranes is nearly 100%, because they are free of interconnected porosity. Although most studies of hydrogen separation membranes have focused on proton-conducting oxides by themselves, we have developed cermet (i.e., ceramic-metal composite) membranes in which metal powder is mixed with these oxides in order to increase their hydrogen permeability. Using several feed gas mixtures, we measured the nongalvanic hydrogen permeation rate, or flux, for the cermet membranes in the temperature range of 500-900°C. This rate varied linearly with the inverse of membrane thickness. The highest rate, ≈32 cm3(STP)/min-cm2, was measured at 900°C for an ≈15-μm-thick membrane on a porous support structure when 100% H2 at ambient pressure was used as the feed gas.

Low-temperature properties of orientationally degenerate (OH)− centers in proton-conducting oxides

2007 ◽  
Vol 33 (4) ◽  
pp. 362-370 ◽  
Author(s):  
M. A. Ivanov ◽  
A. Ya. Fishman ◽  
V. I. Tsidil’kovskiĭ
Keyword(s):  
Low Temperature ◽  
Proton Conducting ◽  
Conducting Oxides
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