| Solid Oxide Fuel Cell(SOFC) is a constant temperature、 solid-state powergeneration unit which can directly transform the chemical energy stored in the fuel andoxidizer into electricity efficiently and environmentally. Traditional SOFC operated at ahigh temperature bring a lot of problems as materials and technology. As well as thelimitation of hydrogen as SOFC fuels, It becames a important research direction aboutproducing SOFCs which can directly used high-energy density hydrocarbon fuels.Because of a number of advantage about microwave heating, such as uniform heating,high utilization of geothermal energy, short heating time, selective heating, smart thermalinertia, easy to control and so on. So it developed fast. The microwave heatingtechnology has matured now and it plays an important role in the powder preparationprocess.This paper around two themes of high activity powders preparation undermicrowave disposal and resistance to carbon deposition of anode when use ofhydrocarbons as fuels. Firstly, High surface activity、uniform and good dispersionpowders have been prepared under microwave disposal. The two single cells have beenmade form difference anode catalyst powders. The electrochemical performance and theimpact of anode microstructure of the two single cells have been studied. Secondly, studyon resistance to carbon deposition performance and stability of single cells which madeform the anode catalyst powders prepared under different conditions when usinghydrocarbons as fuels, and around the difference of SOFC operating conditions,try tofind out ways to reduce or eliminate the anode coking.In experiment, Under the microwave field disposal, Sm0.15Gd0.05Ce0.8O1.9powderprepared by Pecini method and the anode catalyst powder prepared by sol-gel methodhave been made. The study found that the powder made under microwave field disposalis better than the powder made by oven heating. It has a higher surface activity、betteruniform shape、dispersion and more surface defects. Using Pechini method, The cubicfluorite phase of Sm0.15Gd0.05Ce0.8O1.9has basically formed at600℃. Under the effect ofmicrowave field with Pechini method(R=1.5or3), the powder particle size distributebetween14-16nm. After sintering in1400℃, sintered density reached96.5%. And after1600℃calcined4h, the sintered density of the samples reached99.3%. Among thepreparation of anode catalyst powder under microwave field disposal, We found that thereaction rate and particle size matches best when the microwave time is8min and themicrowave powder is220W. The particle size distribution is more narrow and less reunion relatively. The DTA curves show that the powder under microwave disposalheated uniform between inside and outside, loss on ignition is more thorough. Anodeaperture evenly distributed、particle connect better、the catalyst particle size is relativelydecreased、the feature is more uniform these are better for improving cell electrochemicalperformance.When using ethanol as fuel, NiO-CuO/CeO2-YSZ||YSZ||ScSZ-LSM single cellstably operated900min, after it, The powder density of cell rapidly decay to zero in72min because of carbon deposition on anode surface and internal. Infrared spectroscopyfound that the absorption peak of C which is the product of ethanol catalyzed cleavageappear hypchromatic shift, which is caused by significant quantum effects because ofsmaller carbon deposition of C size. FT-IR also shows C has been adsorbed on thesurface of CeO2on anode. After carbon deposition occurred, Cu and CeO2particles havebeen covered by C, electrochemical active sites have blocked and suppressed. SEMindicated that the anode holes have gradually blocked. No sufficient fuel gas and site ofthree phase boundary can provide for single cell. It leads to single cell performancedeclined rapidly. |
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