Physical, chemical and electrochemical properties of pure and doped ceria

Solid oxide fuel cells (SOFCs) have the promise to improve energy efficiency and to provide society with a clean energy producing technology. The high temperature of operation (500−1000 °C) enables the solid oxide fuel cell to operate with existing fossil fuels and to be efficiently coupled with turbines to give very high efficiency conversion of fuels to electricity. Solid oxide fuel cells are complex electrochemical devices that contain three basic components, a porous anode, an electrolyte membrane, and a porous cathode. In this short review, a survey of the types and properties of materials that have been considered for each of these components is presented with an emphasis on the requirements for operation at intermediate temperature (500−800 °C). Some directions for future research are discussed.

Materials for Solid Oxide Fuel Cells

It is well known that urbanization and industrialization have resulted in the rapidly increasing emissions of volatile organic compounds (VOCs), which are a major contributor to the formation of secondary pollutants (e.g., tropospheric ozone, PAN (peroxyacetyl nitrate), and secondary organic aerosols) and photochemical smog. The emission of these pollutants has led to a large decline in air quality in numerous regions around the world, which has ultimately led to concerns regarding their impact on human health and general well-being. Catalytic oxidation is regarded as one of the most promising strategies for VOC removal from industrial waste streams. This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades. It addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions. It also highlights the primary routes for catalyst deactivation and discusses protocols for their subsequent reactivation. Kinetic models and proposed oxidation mechanisms for representative VOCs are also provided. Typical catalytic reactors and oxidizers for industrial VOC destruction are further discussed. We believe that this Review will provide a great foundation and reference point for future design and development in this field.

/pdf/recent-advances-in-the-catalytic-oxidation-of-volatile-zw2c35dbg7.pdf

Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources.

Solid oxide fuel cells: fundamental aspects and prospects

There is an urgent global need for electrochemical energy storage that includes materials that can provide simultaneous high power and high energy density One strategy to achieve this goal is with pseudocapacitive materials that take advantage of reversible surface or near-surface Faradaic reactions to store charge This allows them to surpass the capacity limitations of electrical double-layer capacitors and the mass transfer limitations of batteries The past decade has seen tremendous growth in the understanding of pseudocapacitance as well as materials that exhibit this phenomenon The purpose of this Review is to examine the fundamental development of the concept of pseudocapacitance and how it came to prominence in electrochemical energy storage as well as to describe new classes of materials whose electrochemical energy storage behavior can be described as pseudocapacitive

Pseudocapacitance: From Fundamental Understanding to High Power Energy Storage Materials

Oxygen Ion Conduction of the Fluorite‐Type Ce1 − x Ln x O 2 − x / 2 ( Ln = Lanthanoid Element )

The compounds , which show high electrical conductivity, are electrochemically reduced in an aqueous alkaline solution to give rise to the oxygen deficient state . The electrochemical redox reactions are reversible in the range . The electrode potentials of in a solution have been measured as a function of δ. From these data and the measurements of potential change in the cathodic processes under constant current density, the oxygen ion diffusion constants have been calculated on the basis of a linear diffusion model of oxygen ions in the crystal, which was theoretically derived. The calculated diffusion constants at 25°C are for and, respectively. These values are very large as compared with ordinary oxides.

Electrochemical Behavior of the Perovskite‐Type Nd1 − x Sr x CoO3 in an Aqueous Alkaline Solution

The perovskite-type compounds La1-xMxNiO3 (M: Ca, Sr and Ba) were synthesized and their crystallographic, electric and thermochemical properties were investigated. The regions of perovskite formation were determined. The solubility limits or alkaline earth elements into La sites are around 5% for Sr and Ba, and less than 1% for Ca. The charge compensation of divalent ion substitution into a trivalent La ion site takes place by the formation of oxygen ion vacancies. Lanthanoid elements other than La did not form perovskite-type oxides. The compound LaNiO3 undergoes a rhombohedral-cubic transition at 940?C and decomposes above 1120?C. Resistivity of LaNiO3 is 9?10-3 ?cm at room temperature and increases as the temperature is raised.

https://iopscience.iop.org/article/10.1143/JJAP.14.330/pdf

Some Crystallographic, Electric and Thermochemical Properties of the Perovskite-Type La1-xMxNiO3(M: Ca, Sr and Ba)

A fuel cell using an electrolyte-soluble fuel in which a solid film exhibiting a hydrogen ion- and/or hydronium ion-conducitivty is provided on the surface of an air electrode close to an electrolyte containing the fuel is disclosed. The solid film transmits hydrogen ions and hydronium ions, but it does not transmit water and oxygen in substance. Therefore, the leakage of electrolyte and the variation of the composition ratio of the electrolyte are not feared, so that the fuel cell can be used for a long time.

Fuel cell using electrolyte-soluble fuels

Catalysts for conversion of nitrogen oxides comprises a porous ceramic carrier, and 01 to 10% by weight of copper oxide in terms of copper metal, 01 to 20% by weight of lanthanum oxide in terms of lanthanum metal and 001 to 12% by weight of zirconium oxide in terms of zirconium metal, based on the weight of the carrier, these oxides being supported on the carrier The catalysts are brought in contact with a gas containing nitrogen oxides in the presence of ammonia and sulfur oxides, thereby decomposing and converting the nitrogen oxides

Tetsuichi Kudo

Papers

Oxygen Ion Conduction of the Fluorite‐Type Ce1 − x Ln x O 2 − x / 2 ( Ln = Lanthanoid Element )

Electrochemical Behavior of the Perovskite‐Type Nd1 − x Sr x CoO3 in an Aqueous Alkaline Solution

Some Crystallographic, Electric and Thermochemical Properties of the Perovskite-Type La1-xMxNiO3(M: Ca, Sr and Ba)

Fuel cell using electrolyte-soluble fuels

Method for reducing nitrogen oxides