Fe-N_x/C电催化剂的氧还原性能及配体结构对催化活性的影响  

Performance of Fe-N_x/C Electrocatalysts for Oxygen Reduction Reaction and the Effect of Ligand Stucture on the Catalytic Activity

作　　者：李赏[1] 朱广文[1] 陈锐鑫[1] 王家堂[1] 赵伟[1] 潘牧[1] 

机构地区：[1]武汉理工大学材料复合新技术国家重点实验室燃料电池湖北省重点实验室,武汉430070

出　　处：《高等学校化学学报》2012年第8期1782-1787,共6页Chemical Journal of Chinese Universities

基　　金：中央高校基本科研业务费专项资金(批准号:2011-IV-026);国家"九七三"计划项目(批准号:2012CB215504)资助

摘　　要：以2,6-二氨基嘌呤(Hdap)为配体合成了Fe-Nx/C氧还原催化剂,并优化了热处理温度和Fe含量.对催化剂组成和结构进行了表征,分析了配体Hdap在热处理过程中随温度的变化情况,通过循环伏安法和线性扫描伏安法测试了催化剂的氧还原催化性能.结果表明,热处理温度为800℃,Fe质量分数为5%时,催化剂活性最高.吡啶N含量较高的配体有利于提高催化剂的活性,配体中含S元素会增加催化剂的活性.2,6-Diaminopurine was used as a ligand to prepare Fe-Hdap complexes for the development of a new oxygen reduction reaction （ORR） catalyst. The prepared Fe-Hdap complexes were heat-treated at 600, 700, 800 and 900℃ to optimize their activity for ORR. It was found that the 800 ℃ heat-treatment yielded the most active Fe-NJC catalyst. Fe-Nx/C catalyst with several Fe loadings（3% , 4% , 5% , 6% , 7% , mass fraction） were also synthesized and a 5% Fe loading yielded the best catalytic ORR activity. XRD, TG, TEM, XPS and line-scan vohammograms techniques were used to characterize the structural changes in these catalyst after heat-treatment, including the catalyst composition, structure, morphologe and the electrochemical activity. As observed by XRD, when the heat-treatment temperature or Fe content was too high, Fe3 O4 could be produced. This would lead to a decrease in ORR activity. XPS analysis revealed that the catalyst surface consisted of 0. 61% （mass fraction） N （largely pyrrolic-like）. The ORR activities of catalysts synthesized using ligands with different structures were studied. The result indicated that the catalyst prepared using the compound containing more pyridinic N as ligand had enhanced activity, and the S element in ligand can improve the activity of Fe-Nx/C catalyst. The stability of the Fe-Nx/C catalyst in the voltage region having ORR kinetic limiting was tested by fixing a electrode potential to record the change in current density with time. The obtained degradation rates for this catalyst is 0. 0048 mA/（ cm2 · h）.

关 键 词：质子交换膜燃料电池 2 6-二氨基嘌呤 Fe-Nx/C电催化剂 氧还原活性 

分 类 号：O643.361[理学—物理化学]