SYNTHESIS AND CHARACTERIZATION CODOPED CERIA

• Main Author: ARIE HARDIAN (NIM: 20510023); Pembimbing : Prof. Dr. Ismunandar
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/15000
• Institution: Institut Teknologi Bandung

<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Energy crisis which had been happen because of unbalanced between human energy needed and availability of fossil fuel and the CO2 emission from combustion of fossil fuel which caused global warming effect invite many attentions of people who care with environment to develop much kind of alternative energies immediately which is hoped could reduce the consumption of fossil fuel. Fuel cells which is one of alternative energy which generally use hydrogen fuel have relative high efficiency and environmentally friendly. There are six types of fuel cell which have been developed, but two of them being promising candidate for future energy, those are Polymer Electrolyte Membranes Fuel Cells (PEMFCs) and Solid Oxide Fuel Cells (SOFCs). PEMFCs operated at low temperature (under 100 oC) so these type are suitable for portable devices. SOFCs operated at high temperature (more than 800 oC) so these type are suitable for electrical generator of building such as houses, hospitals, offices, and many more. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> SOFCs have many advantages, such: (1) high efficiency up to 60-70% and > 95% if combined with gas turbine; (2) can use variety of fuels such hydrogen, carbon monoxide, even hydrocarbon; (3) could be fabricated to many kind of size and design; (4) protected from gases contaminated such CO; (5) low cost in fabrication because not using Pt. Nowadays, SOFC development is leads to lowering the operating temperature down to 500-800 oC , which is called Intermediate Temperature SOFC (IT-SOFC). This lowering could decrease fabrication cost and broad applications area of SOFC. However, lowering the operating temperature could increase electrolyte resistance and inhibited catalytik reaction rate in electrodes. Finding new combination between electrolyte and electrodes which each of them has good conductivity and good electrocatalytic become a challenge for researchers. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Doped ceria is one of good candidate for IT-SOFC electrolyte; it was because it has higher conductivity compare to commercial electrolyte yttria stabilized zirconia (YSZ) at intermediate temperature. Unfortunately, doped ceria is easy form n type conductor at low oxygen partial pressure and high operating temperature which caused reduction of Ce4+ to Ce3+. Searching ideal dopant including its concentration has been done to improve the stability and conductivity of ceria at low temperature. Some researcher reported that codoping strategy could increase conductivity and stability of ceria more than their single doped. Synthesis of codoped ceria Ce1-x-yGdxMyO1-delta where M = Er, Dy, or Nd, and x, y = 0.05 atau 0.1 had been done using solid state method. Structure, morphology, and composition of synthesized codoped ceria are characterized using XRD, SEM, and EDS respectively. XRD analysis showed that XRD patterns of synthesized codoped ceria seem similar to the XRD pattern of undoped ceria but a little shift and broad peaks. Refinement had been done using Le Baile method to the XRD patterns. All of synthesized codoped ceria have cubic structure with space group Fm3 m. Correlation between lattice parameter of codoped ceria and cation radii mean followed Vegard’s rule at the same total dopants concentration. SEM image showed that most of synthesized codoped ceria have expected surface for an solid electrolyte which is dense. Analysis in porosity and crystallite size had been done using ImageJ software with PoreAnalysisSEM plugin. Porosity of synthesized codoped ceria are in the range 0.00% until 41.55% and the range of crystallite size mean is 2.85-11.56 (mu)m. Based on EDS results, most of synthesized codoped ceria have good agreement composition with target composition.