Sumittra Charojrochkul

Combustion Synthesis of Nanoparticles CeO2 and Ce0.9Gd0.1O1.95

Ceria and Gd2O3 doped ceria nanoparticle powder has been fabricated using a combustion synthesis method for an application as an electrolyte for Intermediate Temperaure Solid Oxide Fuel Cell (ITSOFC). The nanoparticle powder is obtained when the processing parameters are optimized. Three different fuels i.e. urea, citric acid and glycine have been used for producing the nanoparticle powder of doped ceria. The produced particles have been characterized using SEM for the particle morphology, XRD for phase identification, and particle analysis for the particle size distribution and identification. In addition, these particles have shown good reforming activity, which provide an opportunity for this material not to be used only as an electrolyte but also as a support for the anode part of SOFC.

Bioethanol-Fuelled Solid Oxide Fuel Cell System for Electrical Power Generation

Tremendous consumption of energy to serve daily lives and economic activities has led to the critical problem of energy shortage since the current main energy sources rely on fossil fuels which are non-renewable. Therefore, efficient renewable energy sources need to be investigated and improved to replace or substitute the use of fossil fuels to alleviate environmental impacts while being sustainable. Biomass-derived fuels are recognized as promising alternatives among other renewable sources e.g. wind, solar, geothermal, hydropower, etc. This fuel can be produced from various available agricultural materials, hence there is no problem of feedstock supply. Instead, its use is beneficial for those countries having strong background in agriculture. In addition, this agro-based fuel can provide a CO2-closed cycle as the CO2 released from the fuel combustion can be redeemed with the CO2 required for biomass growth. Bioethanol plays an important role as a promising renewable energy among other biofuels due to its useful properties such as high hydrogen content, non-toxicity, safety, ease of storage and handling (Ni et al., 2007). An efficient energy conversion system is required to maximize bioethanol fuel utilization to obtain a full performance. Combustion heat engines which are widely used nowadays have a low conversion efficiency of power production due to losses during multiple energy conversion stages as well as a low value of chemical energy of bioethanol represented by LHV or HHV compared to those of fossil fuels (C6 hydrocarbons or above). Moreover, electrical energy efficiency produced from a combustion heat engine becomes even lower because of further losses from more energy conversion stages. Fuel cell technology is considered to be an interesting alternative for efficient energy conversion since it can directly convert chemical energy stored in the fuel into electrical energy via electrochemical reaction. Less energy is lost in the fuel cell operation and higher electrical efficiency can be obtained. However, the problems in using fuel cell technology such as short-life operating time, high manufacturing cost and impromptu infrastructure support are still issues to be tackled. The Solid Oxide Fuel Cell (SOFC), a type of fuel cells, is selected to be an electrical

Properties of Gd Substituted Lanthanum Cobalt Iron Oxide as Cathode for IT-SOFCs

In an effort to reduce thermal expansion coefficient (TEC) of the (La,Sr)CoO3 materials while maintaining adequate electrical conductivity, Gd substitution on A site of La0.6Sr0.4Co0.4Fe0.6O3-δ was investigated as a potential cathode for IT-SOFCs. La0.6xGdxSr0.4Co0.4Fe0.6O3-δ (LGSCF) powders with x = 0.1-0.6 were prepared via solid state reaction method by ball milling the starting materials in ethanol and calcining the starting powder at 1100C for 10 hours. X-ray diffraction analysis performed on the samples revealed rhombohedral symmetry for all samples. An increase in Gd substitution amount was found to decrease TEC and conductivity of the compounds. The TEC obtained was in the range of 14.6-16.2×10 /C from room temperature to 600C. However, detrimental effect of the substitution on electrical conductivity was observed upon Gd substitution. The conductivity values were found to range from 60-210 S/cm with higher conductivity for lower Gd contents.