| As one of the critical materials used in Proton Exchange Membrane Fuel Cell (PEMFC), cathode catalyst has great effect on the performance and lifetime of fuel cells. At present, Pt/C catalyst is most commonly used, but for the lack of Pt material in the world and its expensive, extensive commercial application of PEMFC faces barriers. It becomes more and more necessary to find out some non-noble catalysts with lower cost. In this paper, perovskite-type catalysts Pr1-xCaxCoO3 (PCCO) were synthesized by sol-gel method, and their structure and properties were also studied, the results indicated that:(1) Nano-Pro.6Cao.4Co03 was successfully synthesized by sol-gel method, using citric acid as complexing agent, X-ray diffraction verified the catalysts with single perovskite-type phase, and no impurity phase exists.(2) Grading analysis and TEM analysis show that, PCCO series catalysts synthesized in this paper were all nano materials with particle size between 27nm and 50nm.(3) The catalytic activity of catalysts was improved significantly after doping Ca2+. The ORR current density of catalyst PrCoO3 was 0.60mA/cm2 at-0.2V (vs.SCE), and Pro.6Cao.4Co03 reached 1.13 mA/cm2@-0.2V (vs.SCE), improved about two times. As the amount of Ca2+ doping increased, the catalytic activity of Pr1-xCaxCoO3 increased firstly and then declined, activity order of different doping amount was:Pro.6Cao.4CoC3>Pr0.5CA0.5CoO3>Pr0.7Ca0.3CoO3>Pr0.8Ca0.2CoO3> Pr0.9Ca0.1CoO3.(4) The ORR activity of Pr1-xCaxCoO3 at different heat treatment temperatures was different, activity order was:750℃>850℃>650℃, it's related to the crystal size.(5) Catalytic mechanism of perovskite-type oxides was preliminary explored in this paper:Co3+-O-Co4+ ion pair existed in Pr1-xCaxCoO3 is the most important factor which can improve its ORR activity. Co3+-O-Co4+ becomes the active centers of the catalyst, it can effectively promote four electrons process in the oxygen reduction reaction.
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