石墨纳米纤维用作质子交换膜燃料电池催化剂载体

利用质子交换膜燃料电池用过的废旧碳纸,采用球磨法制备了石墨纳米纤维(GNF,BET比表面积为229·3m2/g),并以GNF作为载体制备了Pt/GNF催化剂(电化学比表面积为98m2/g).与传统的以VulcanXC-72碳黑为载体的Pt/XC-72催化剂相比,其电化学比表面积及Pt粒径大小相近.采用恒电位氧化法考察了GNF,XC-72,Pt/GNF和Pt/XC-72的电化学稳定性.结果表明,在相同条件下,XC-72的峰电流增加了60%,而GNF增加了2%;Pt/XC-72的腐蚀电流比Pt/GNF的大40%;恒电位氧化60h后,Pt/XC-72约有84·7%的电化学比表面积损失,Pt/GNF仅损失37·2%.这表明GNF的抗腐蚀性优于XC-72,有希望成为质子交换膜燃料电池抗腐蚀的催化剂载体.

Graphite Nanofibers as Catalyst Support for Proton Exchange Membrane Fuel Cells

By a ball-milling method,graphite nanofibers(GNF) were prepared from used carbon paper in proton exchange membrane fuel cells.The surface area of GNF was 229.3 m2/g.20% platinum was loaded on the GNF and XC-72 to fabricate Pt/GNF and Pt/XC-72 supported catalysts.The results of cyclic voltammetry showed that the Pt/GNF catalyst had the same electrochemical surface area(ESA) as the Pt/XC-72 catalyst.The morphology of these catalysts was characterized by transmission electron microscopy.The electrochemical stability was measured for XC-72,GNF,Pt/XC-72,and Pt/GNF electrodes by the constant-potential oxidation.The peak current increased by 2% for GNF while 60% for XC-72.The corrosion current for Pt/XC-72 was 1.4 times of that for Pt/GNF.In addition,almost 84.7%ESA was lost for Pt/XC-72 catalyst after oxidation for 60 h,while only 37.2%ESA was lost for Pt/GNF.The results indicated that GNF possessed much higher resistance to electrochemical oxidation than XC-72.