Acessibilidade / Reportar erro

Synthesis and evaluation of solid oxide fuel cell (SOFC) with anode based on nickel and cobalt

A unitary solid oxide fuel cell (SOFC) was prepared and evaluated for the electric energy generation, using methane and hydrogen as fuel. The cell anode was made with the electro-catalyst developed and characterized in this work (CATAC). CATAC was prepared by the mechanical mixture of zirconia stabilized with ytria (YSZ) and the metallic precursors (nickel and cobalt nitrate, hexahydrated), adding 25% of citric acid to the total mass, and finally calcined at 800°C for four hours in air. The catalyst was characterized by X-ray fluorescence (XRF) and X-ray photo-electronic spectroscopy (XPS), which did not indicate any electronic interaction between nickel and cobalt; CATAC metal content was approximately 35% in mass. CATAC was tested for the hydrogen generation from methane vapor reforming, showing good productivity starting at 600ºC. The anode/electrolyte/cathode structure was prepared by pressing a layer of CATAC mixed with graphite, a pure YSZ layer, and a layer of lanthanum, strontium and manganese mixed oxide (LSM) and graphite. The set was then pressed and sintered at 1380°C for four hours. Platinum screens were fixed, with the aid of platinum ink, on the anode and cathode surfaces; the structure was heated to 1100°C. The system was glued to an alumina reactor using high temperature ceramic bond. SEM micrographs of the anode/electrolyte/cathode structure showed porous electrode and dense electrolyte, in a well sintered ceramic set. The unitary SOFC was tested using methane or hydrogen as fuel, at three different temperatures. The tension varied inversely proportional with the current, when measured at 850 or 950ºC and hydrogen, but the tension was constant above five mV at 800ºC, with methane. The unitary cell showed a satisfactory performance for electricity generation with both methane and hydrogen as combustible.

Cooperative net; fuel cell; solid oxide; catalyst; nickel; cobalt; YSZ


Laboratório de Hidrogênio, Coppe - Universidade Federal do Rio de Janeiro, em cooperação com a Associação Brasileira do Hidrogênio, ABH2 Av. Moniz Aragão, 207, 21941-594, Rio de Janeiro, RJ, Brasil, Tel: +55 (21) 3938-8791 - Rio de Janeiro - RJ - Brazil
E-mail: revmateria@gmail.com