Optimized mixed ionic–electronic conductivity in two-phase ceria–zirconia composite with cobalt oxide and Na2CO3 as suitable additives

2016 ◽  
Vol 4 (12) ◽  
pp. 4402-4412 ◽  
Author(s):  
Aditya Maheshwari ◽  
Hans-Dieter Wiemhöfer
Keyword(s):  
Cobalt Oxide ◽  
Sodium Carbonate ◽  
Electronic Conductivity ◽  
Composite Membranes ◽  
Electronic Conduction ◽  
Doped Ceria ◽  
Two Phase ◽  
Mixed Ionic Electronic Conductivity

Excellent mixed ionic–electronic conduction was achieved in composite membranes of Ta doped ceria (TDC) and Y doped zirconia (YSZ) by suitable amounts of cobalt oxide and sodium carbonate.

Synthesis of Nanosize Ceria by a Combustion Process and Electrical Characterization of HeteroFoaM Porous Ceria Electrodes

2011 ◽  
Author(s):  
J. Wright ◽  
A. V. Virkar
Keyword(s):  
Oxygen Sensor ◽  
Electronic Conductivity ◽  
Combustion Process ◽  
Electrical Characterization ◽  
Electronic Conduction ◽  
Thermal Treatments ◽  
Powder Samples ◽  
Uniform Composition ◽  
Mixed Ionic Electronic Conductivity

Nanosize powders of Sm2O3-doped CeO2 (SDC) containing various dopants (Pr, Rh, Re) were synthesized using respective nitrates and D-gluconic acid (DGA) by a combustion process. The resulting powders were extremely fine (nanosize) and of uniform composition. Porous samples with open porosity were fabricated by sintering. Electrical conductivity was measured by a four probe DC technique over a wide pO2 range and a temperature range between 200°C and 800°C. The pO2 was measured using an oxygen sensor. Samples of SDC and SDC with Pr doping exhibited significant electronic conduction in reducing atmospheres above 400°C. Thus, these materials are suitable candidates for SOFC anodes above 400°C. Sintered and powder samples were subjected to various thermal treatments in several atmospheres (oxidizing to reducing) and were characterized by XRD, SEM, and XPS. The purpose of adding the dopants Pr, Rh and Re was to create mixed ionic electronic conductivity in reducing atmospheres at low (<300°C) temperatures. Such materials are potential candidates as SOFC anodes at temperatures possibly lower than 500°C.

Characteristics of Ni/Nd-Doped Ceria Anode For Solid Oxide Fuel Cell

1995 ◽  
Vol 411 ◽  
Author(s):  
H. Nagamoto ◽  
K. Kumagai ◽  
H. Murayama
Keyword(s):  
Fuel Cell ◽  
Oxygen Partial Pressure ◽  
Electronic Conductivity ◽  
Solid Oxide ◽  
Mixed Conductor ◽  
Electronic Conduction ◽  
Doped Ceria ◽  
Oxide Fuel ◽  
Triple Phase Boundary ◽  
Electrode Resistance

ABSTRACTA fuel electrode consisting of particles of Ni and mixed conductor, Nd-doped ceria (NDC) has been developed. The electrode resistance decreased with decreasing the oxygen partial pressure lower than 10−11 atm, where the electronic conduction is predominant for NDC. This decrease in the resistance could be attributed to an increase in the triple phase boundary caused by an increase in electronic conductivity of NDC.

The Crystal Structure, Conductivity Character and Ionic Migration of Samarium Doped-Ceria (SDC) and its Composite with Sodium Carbonate

2014 ◽  
Vol 896 ◽  
pp. 49-53 ◽  
Author(s):  
Fitria Rahmawati ◽  
Dani Gustaman Syarif ◽  
Putri Pradnya Paramita ◽  
Eddy Heraldy
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Sodium Carbonate ◽  
Single Phase ◽  
Short Circuit ◽  
Electronic Conductivity ◽  
Doped Ceria ◽  
Cell Parameters ◽  
Fuel Cell Performance ◽  
Carbonate Salt

This paper discusses the crystal structure, the conductivity character and ionic migration inside Sm0.2Ce0.8O1.9 (SDC) crystal and it’s composite with sodium carbonate salt, Na2CO3 (NSDC). XRD measurement equipped with Le Bail refinement shows that SDC crystallized in single phase of cubic with space group of Fm3m. The addition of Na2CO3 does not change the crystal structure of SDC however it increases the cell parameters. NSDC has a lower ionic conductivity than the SDC at the same temperature. However at 600 °C, SDC provides electronic conductivity which indicates the diffusion of electrons between the electrolyte and electrode caused by the reduction of Ce(IV) to Ce(III). It may cause a short circuit and the fuel cell performance if it is used as electrolyte. Meanwhile, NSDC still produces pure ionic conductivity at 600 °C which indicates a better chemical stability. Based on its capacitance values, it is known that the ionic conductivity of SDC is generated by migration of ions inside grain, while the conductivity of NSDC is generated by the migration of ions between grains or it is named as grain boundaries conductivity.

Mixed ionic-electronic conductivity features of A-site deficient Nd nickelates

2020 ◽  
Vol 46 (16) ◽  
pp. 25527-25535 ◽  
Author(s):  
V.A. Sadykov ◽  
E.M. Sadovskaya ◽  
E.A. Filonova ◽  
N.F. Eremeev ◽  
N.M. Bogdanovich ◽  
...  
Keyword(s):  
Electronic Conductivity ◽  
A Site ◽  
Mixed Ionic Electronic Conductivity

scholarly journals A Mini Review on Lanthanum Ferrites-based Exsolved Perovskites as Fuel-flexible Anode for Solid Oxide Fuel Cells

2020 ◽  
Author(s):  
Massimiliano Lo Faro ◽  
Sabrina Campagna Zignani ◽  
Antonino S. Aricò
Keyword(s):  
Substrate Surface ◽  
Electronic Conductivity ◽  
Solid Oxide ◽  
Full Density ◽  
Thermal Treatments ◽  
Direct Oxidation ◽  
Ni Doping ◽  
Shell Nanoparticles ◽  
Two Phase ◽  
Sulphur Poisoning

Exsolved perovskites can be obtained from lanthanum ferrites, such as La0.6Sr0.4Fe0.8Co0.2O3, as result of Ni doping and thermal treatments. Ni can be simply added to the perovskite by an incipient wetness method. Thermal treatments include calcination in air (e.g., 500 &deg;C) and subsequent reduction in diluted H2 at 800 &deg;C to favor the exsolution process. The chemistry of the nanoparticles exsoluted on the substrate surface can be further modulated by a post treatment in air. These processes allow to produce a two-phase material consisting of a Ruddlesden-Popper type structure and a solid oxide solution e.g. &alpha;-Fe100-y-zCoyNizOx oxide. The formed electro-catalyst shows sufficient electronic conductivity under reducing environment at the SOFC anode. Outstanding catalytic properties are observed for the direct oxidation of dry fuels in SOFCs, including H2, methane, syngas, methanol, glycerol and propane. This anode electrocatalyst can be combined with full density electrolyte based on Gadolinia-doped Ceria or with La0.8Sr0.2Ga0.8Mg0.2O3 (LSGM) or BaCe0.9Y0.1O3-&delta; (BYCO) to form a complete perovskite structure-based cell. Moreover, the exsolved perovskite can be used as a coating layer or catalytic pre-layer of a conventional Ni-YSZ anode. Beside the excellent catalytic activity, this material also shows proper durability and tolerance to sulphur poisoning. In this mini review, preparation methods, physico-chemical characteristics, surface properties of exsoluted and core-shell nanoparticles encapsulated on the metal-depleted perovskite substrate surface, electrochemical properties for the direct oxidation of dry fuels and related electrooxidation mechanisms are examined and discussed.

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