Abstract:

This paper investigates the anode and cathode catalysts for an intermediate·temperature proton-conducting membrane H₂S fuel cell based on the requirements of three·phase boundary theory.By investigating the perform ances and chemical stabilities of three anode catalysts,namely,Pt,MoS₂ and composite metal sulfide(MoS₂/NiS)in the condition of electrochemical oxidation of hydrogen sulfide,it is indicated that MoS2 and MoS2+NiS exhibit better cata-lytic activity than Pt,and that,at a temperature more than 450℃,MoS2 itself sublimes, while the composite cata-lyst MoS₂/NiS containing both Mo and transition metal Ni remains stable.Moreover,by the research on the electro-chemical performances of two cathode catalysts such as Pt and composite NiO,it is shown that(1)composite NiO is of lower over—potential and better electrochemical performance;and(2)the poor electrical conductivity of com-posite electrodes(anode or cathode)can be overcome by admixing Ag powder into the catalyst layer with a dosage of 10% by weight.Finally,by the investigation into the electrochemical perform ance of the fuel cell made of H₂S,(MoS₂+NiS+Ag+electrolyte+starch)/Li₂SO₄-Al₂O₃/(NiO+Ag+electrolyte+starch),air at 101.13 kPa and 600~680℃,it is revealed that the highest delivered current,power densities of the cell can reach 240 mA/cm² and 70 mW/cm² at 680℃,respectively.

Key words: fuel cell, electrode, catalyst, hydrogen sulfide