FRANCISCO NOBUO TABUTI
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Artigo IPEN-doc 30176 Steam reforming catalytic layer on anode-supported and metal-supported solid oxide fuel cells for direct ethanol operation2023 - MACHADO, MARINA; TABUTI, F.; PIAZZOLLA, F.; MORAES, T.; ABE, R.; GUIMARAES, R.M.; MIURA, Y.; FUKUYAMA, Y.; FONSECA, F.C.A catalyst based on lanthanum chromite with exsolved metallic ruthenium nanoparticles (LaCrO3-Ru) was applied as a catalytic layer for internal ethanol steam reforming of anode-supported and metal-supported solid oxide fuel cells. The metal support exhibits limited catalytic properties for the ethanol steam reforming reaction. Thus, the LaCrO3-Ru catalysts were optimized for operating temperatures in the 600-700 °C range to promote stable ethanol reforming. The catalytic layer had no significant impact on the electrochemical properties of the fuel cell, and samples with and without the catalytic layer exhibited similar performance in hydrogen. Initial durability tests with LaCrO3-Ru layer have shown that the catalytic layer plays a crucial role in the stability of the metal-supported fuel cell under ethanol.Artigo IPEN-doc 28527 Exploring the stability of direct ethanol solid oxide fuel cells at intermediate temperature2021 - FONSECA, F.C.; TABUTI, F.; MORAES, T.; ABE, R.; GUIMARAES, R.M.; MIURA, Y.; FUKUYAMA, Y.Anode supported fuel cells were tested in direct (no water added) bioethanol at intermediate temperature (600°C and 700°C). The standard fuel cell has reasonable short-term stability under dry ethanol if current is continuously drawn at a minimum fuel utilization factor at 700ºC. However, the YSZ/Ni anode develops carbon deposits as inferred from post fuel cell test analyses and fixed bed steam reforming catalytic tests at 600°C. Thus, an active catalytic layer with tailored properties for ethanol internal reforming was studied. Initial tests investigated the Ir/gadolinium-doped ceria catalysts previously proven stable at 850°C. The main results have shown that the catalytic layer has no significant effect on the performance of the fuel cell running under hydrogen. The use of a ceria-based catalytic layer has enhanced the stability of the fuel cell under dry ethanol at 700°C, but stable operation at 600°C requires the development of more active catalyst.Artigo IPEN-doc 27544 The role of the ceria dopant on Ni / doped-ceria anodic layer cermets for direct ethanol solid oxide fuel cell2021 - SILVA, A.A.A. da; STEIL, M.C.; TABUTI, F.N.; RABELO-NETO, R.C.; NORONHA, F.B.; MATTOS, L.V.; FONSECA, F.C.The effect of ceria dopant aiming at stability in Ni/doped-ceria anodic layers for direct ethanol solid oxide fuel cells (SOFC) was studied. Solid solutions of ceria doped with Y, Gd, Zr, or Nb (10 mol%) impregnated with NiO were tested in a fixed bed reactor for ethanol conversion reactions and for direct (dry) ethanol SOFC. The ceria dopant showed a marked effect on both the catalytic and the electrical transport properties of the ceramic support. Catalytic activity data revealed that the studied materials deactivate in ethanol decomposition reaction but are stable for ethanol steam reforming. Thus, feeding dry ethanol to the SOFC with a Ni/doped-ceria anodic catalytic layer evidenced that water produced from the electrochemical hydrogen oxidation provides steam for the internal reforming resulting in great stability of the fuel cells tested during ~100 h. The combined catalysis and SOFC results demonstrate Ni/doped-ceria is as candidate anode layer for stable SOFC running on bioethanol.Artigo IPEN-doc 23095 Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells2017 - NOBREGA, SHAYENNE D. da; MONTEIRO, NATALIA K.; TABUTI, FRANCISCO; FLORIO, DANIEL Z. de; FONSECA, FABIO C.Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium- doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs.