Geopolymer/CeO2 as Solid Electrolyte for IT-SOFC

Abstract

As a material for application in the life sciences, a new composite material, geopolymer/CeO2 (GP_CeO2), was synthesized as a potential low-cost solid electrolyte for application in solid oxide fuel cells operating in intermediate temperature (IT-SOFC). The new materials were obtained from alkali-activated metakaolin (calcined clay) in the presence of CeO2 powders (x = 10%). Besides the commercial CeO2 powder, as a source of ceria, two differently synthesized CeO2 powders also were used: CeO2 synthesized by modified glycine nitrate procedure (MGNP) and self-propagating reaction at room temperature (SPRT). The structural, morphological, and electrical properties of pure and GP_CeO2-type samples were investigated by X-ray powder diffraction (XRPD), Fourier transform infrared (FTIR), BET, differential thermal and thermogravimetric analysis (DTA/TGA), scanning electron microscopy (FE-SEM), energy dispersive spectrometer (EDS), and method complex impedance (EIS). XRPD and matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) analysis confirmed the formation of solid phase CeO2. The BET, DTA/TGA, FE-SEM, and EDS results indicated that particles of CeO2 were stabile interconnected and form a continuous conductive path, which was confirmed by the EIS method. The highest conductivity of 1.86 × 10−2 Ω−1 cm−1 was obtained for the sample GP_CeO2_MGNP at 700 °C. The corresponding value of activation energy for conductivity was 0.26 eV in the temperature range 500–700 °C.

Revealing the Effect of Synthesis Conditions on the Structural, Optical, and Antibacterial Properties of Cerium Oxide Nanoparticles

“…Some properties, such as quantum confinement as well as high surface-to-volume ratio, induced by the nanosized dimensions of the cerium oxide, together with the low redox potential of the Ce 4+ /Ce 3+ couple, determine heterogeneous processes at the nanoparticle surface in contact with air or liquid. Industrial applications of the materials based on cerium oxide nanoparticles include UV protective materials [1], oxygen sensor and storage [2,3], catalysis [4,5], and solid oxide fuel cells [6,7]. Reversible redox reaction of the Ce 4+ /Ce 3+ couple determines the pro-or antioxidant properties of cerium oxide nanomaterials with potential utilizations in medicine, playing a dual role as a cell protector against oxidative stress, but also as a sensitizer in cancer radiotherapy or in antibacterial applications [8,9].…”

Rice Husk Ash/Silicone Rubber-Based Binary Blended Geopolymer Coating Composite: Fire Retardant, Moisture Absorption, Optimize Composition, and Microstructural Analysis

“…Biomass wastes such as rice husk ash and palm oil fuel ash have been recycled as sources [ 6 , 7 ]. Other common sources are metakaolin [ 8 , 9 ], fly ash [ 10 ], and ground granulated blast-furnace slag (GBBS) [ 11 ]. Geopolymer coating using RHA as the aluminosilicate source has shown excellent fire retardant properties.…”

Alkali activation of different type of ash as a production of combustion process

“…The new standard introduces a quality control system for fly ash, consisting of an internal quality control by the producer and an audit testing by a certification body which is notified by the building authorities. The European Union has approved the use of fly-ash derived from the co-combustion of coal with wood, straw, olive husks, green wood, cultivated biomass, animal meal, municipal solid waste and paper sludge as a cement admixture, as long as the fly-ash contains less than 5 wt % carbon, 5 wt % total alkali, and 0.1 wt % chloride [7][8][9][10][11][12][13][14][15]. Finding means of utilizing waste products is a very important and actual field of research.…”