Study On Preparation Of Anode/Electrolyte Assembly And Desulfization Process Of H₂S-Air Fuel Cell

Fuel cell method was adopted to investigate the desulfur process of H₂S, and the electrochemical performance of the fuel cell utilizing H₂S as fuel gas was tested. Glycine-Nitrate process was selected to prepare ceria-based oxygen ion electrolyte at three different Sm:Ce ratio, suh as 1:9, 2:8 and 3:7. The electrochemical performance tests were carried out on the single H₂S-Air SOFC. The results indicate that the highest open circuit voltage(OCV), 0.59 V , and power output, 6.2 mW·cm^-2, are obtained on the electrolyte when the ratio of Sm to Ce is equal to 2:8. The operation conditions, such as temperature and fuel flow rate, both have great effect on the SOFC performance. The power output increases with the elevated temperature and fuel flow rate, while voltage decreases in linearity with the current density. OCV varies complicatedly with the operation conditions because of the self-decomposition of H₂S, as well as because of the limit of catalytic reaction of H₂S in anode.Urea combustion method was adopted to prepare MCeO₃ doped with Zr (M=Ca, Sr, Ba), proton conductor with perovskite structure. In the single fuel cell with three different electrolytes prepared, the highest OCV, 0.72V and the max power output, 1.55 mW·cm^-2 , are obtained in BCZY as electrolyte. The results are consistent with their conductivity. The improved Co-Mo composite metal sulfide (1:lmolar ratio) was adopted to substitute M0S2 as anode, and the results show that the power output of H₂S-Air SOFC has improved to 3.5 mW·cm^-2. In the mid-temperature, such as 600℃-800℃, the voltage is also enhanced with the elevated temperature and fuel flow rate.A proton-type solid oxide fuel cell reactor (SOFCR), in which Co-Mo composite metal sulfide (2:3 molar ratio) as anode, was applied to removal H₂S and regenerate sulfur. The results indicate that conversion of H₂S is proportional to temperature (t), current density (i) and time (T) in a certain arrange, while is inversly proportional to fuel flow rate (R_h2s)- The max conversion of H₂S in the experiments was obtained to 71% at the condition of R_h2s=30ml/min, t=800℃ and i=12.0 mA·cm^-2. A mathematic model was used to validate that in the proton-type H₂S-Air SOFCR, two steps reaction happen in the anode, one is the thermal decomposition of H₂S and the other is the competitively electrochemical reaction of H₂S and H₂. The cyclic voltammetry method was adopted to evaluate the electrocatalytic activity of anode in H₂S-Air SOFC.