FRANCISCO NOBUO TABUTI
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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 24416 Anodic layers based on doped-Ceria/Ni cermet for direct ethanol fuel cells2017 - SILVA, A.A. da; TABUTI, F.N.; MATTOS, L.V.; STEIL, M.C.; NORONHA, F.B.; FONSECA, F.C.Ceria-based/Ni cermets were studied as the catalytic layer deposited onto the standard yttria-stabilized zirconia/Ni anode for direct ethanol solid oxide fuel cells. The influence of the dopant on both Zr- and Nb-doped (10 mol%) ceria and pure ceria was investigated on the properties of cermets with Ni ~15% volume fraction. Electrolyte-supported fuel cells with ceria-based/Ni catalytic layer were tested for ~100 hours under (dry) ethanol. Fuel cells using the different ceria/Ni cermets showed excellent stability on ethanol, irrespectively of the different properties of the ceramic phase of the catalytic layer. Fuel cells results confirmed that the studied ceria-based cermets are stable catalysts towards ethanol steam reforming.