采用化学还原法及水热法制备了具有树枝状结构的铂-银气凝胶,并对其进行酸碱刻蚀再处理获得刻蚀后的铂-银气凝胶催化剂.利用 X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等表征了铂-银气凝胶的结构、组成及微观形貌.利用循环伏安法(CV)和线性扫描伏安法(LSV)测试了催化剂对氧还原反应(ORR)的电催化活性和稳定性.结果表明,刻蚀后的Pt-Ag气凝胶具有优异的ORR活性,在0.9 V处,刻蚀后Pt-Ag气凝胶的质量比活性和面积比活性分别为166.3 mA/mgPt和0.295 mA/cm2,分别是商业铂/碳催化剂(20%Pt/C)的2.0倍和1.8倍.该催化剂还具有优异的稳定性,循环5000周后,动力学催化质量比活性和面积比活性分别只降低了6.1%和9.1%,远小于商业Pt/C的35%和52.1%.%The etched-platinum-silver aerogel(e-Pt-Ag gel)electrocatalysts with dendritic morphology were synthesized by chemical reduction and hydrothermal method, in which silver nanoparticles were removed by acid-and alkali-etching. X-ray diffraction(XRD), scanning electronic microscopy(SEM)and transmission electron microscopy(TEM)were employed to characterize the composition, structure and morphology of e-Pt-Ag gel. The activity and stability of the catalysts for oxygen reduction reaction(ORR)were studied by cy-clic voltammetry(CV)and linear sweeping voltammetry(LSV)methods. The results show that the e-Pt-Ag gel exhibits excellent ORR performance and favorable durability. In detail, the mass and specific activities of e-Pt-Ag gel at 0.9 V are 166.3 mA/mgPtand 0.295 mA/cm2,respectively,which are 2.0 and 1.8 times that of the commercial Pt/C catalyst[84.9 mA/mgPtand 0.163 mA/cm2]. Furthermore, the mass and space activities of the e-Pt-Ag gel only decay 6.1% and 9.1%, respectively, after 5000 electrochemical cycles, showing higher durability of the e-Pt-Ag gel compared with Pt/C(35%,52.1%).
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