Cathode catalysts comprising composite NiO,NiO-Pt,or LiNiO2 have been developed for electro- chemical oxidation of hydrogen sulfide in intermediate-temperature solid oxide fuel cells(ITSOFCs).All catalysts exhibited good electrical conductivity and catalytic activity at operating temperature.Composite NiO catalysts were found to be more active and have lower over potential and higher current density than pure Pt although the electri- cal conductivity of NiO itself is lower than that of Pt.This problem has been overcome by either admixing as high as 10%(by mass)Ag powder into NiO cathode layer or using composite NiO catalysts such as NiO-Pt and LiNiO2 catalysts.Composite catalysts like NiO with Ag,electrolyte and starch admixed,NiO-Pt,which was prepared from a mixture of NiO and Pt powders,by admixing electrolyte and starch,and LiNiO2,which is derived from the reac-t ion of LiOH?H 2O and NiO with electrolyte and starch admixed have been shown to be feasible and effective in an intermediate-temperature H2S-air fuel cell.A fuel cell using Li2SO4-based proton-conducting membrane as electro-lyte,metal sulfides as anode catalysts,and composite NiO as cathode catalysts produced a maximum current density about 300mA·cm-2and maximum power density over 80 mW·cm-2at 680℃.
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