通过1700℃高温处理XC-72CB得到石墨化碳黑(GCB),并采用酸处理对GCB碳载体进行官能团修饰.透射电子显微镜(TEM)、X射线粉末衍射(XRD)和拉曼光谱的结果显示,酸处理后GCB的石墨化程度增加;N2吸附-脱附结果证明GCB比表面积减小,微孔数量减少;热重分析结果表明,GCB热稳定性增强;红外光谱和拉曼光谱结果显示,GCB表面引入了含氧官能团,并同时保持了GCB的有序化结构.采用循环伏安(CV)法和线性扫描伏安(LSV)法测试了不同预处理后催化剂的电化学性能,表明其电化学活性表面积(ECSA,75.25 m2/g)和质量比活性(MA,0.093 A/mg)均高于商业Pt/C(JM)催化剂.TEM结果表明,使用经过浓硫酸和浓硝酸混合酸处理的GCB(简称OGCB)作为载体得到的Pt/OGCB平均粒径为2.28 nm,略小于商业Pt/C(JM)催化剂(约2.5 nm);经5000周电化学循环伏安测试后,Pt/OGCB的电化学活性表面积衰减17.3%,质量比活性衰减29.5%,而Pt/C(JM)的ECSA衰减达到25.1%,MA衰减达到42.5%.
The graphitized carbon black(GCB) was obtained by a high temperature(1700 ℃) treatment of the XC-72 commercial carbon black(XC-72 CB). The functional groups of GCB were modified by acid treatment. Transmission electron microscopy(TEM),X-ray diffraction,Raman spectrum and infrared spectroscopy displayed the GCB with acid treatment had a higher degree of graphitization. Oxygen- containing functional groups were introduced into the GCB surface and the ordered structure of the GCB was maintained at the same time. Nitrogen adsorption and desorption experiment showed the GCB had smaller specific surface area and less micropore compared to XC-72 CB. Thermogravimetric analysis showed that GCB had the better heat stability.Cyclic voltammetry and linear sweep voltammetry test showed that the electrochemical specific activity area(ECSA)(75.25 m2/g) and the mass activity(MA)(0.093 A/mg) of conc. H2SO4 and conc. HNO3 treated GCB(abbreviated as OGCB) were higher than those of the commercial one. TEM showed the Pt/OGCB had an average particle diameter of 2.28 nm,smaller than the commercial one. After durability test of 5000 cycles,the ECSA and MA of Pt/OGCB decreased by 17. 3% and 29. 5%,respectively,smaller than those of Pt/C(JM)(25.1% and 42.5%). Both activity and durability performance of Pt/OGCB catalyst were better than those of commercial Pt/C(JM) catalyst in oxygen reduction reaction. In addition,in single cell test,the durability of Pt/OGCB catalyst was also better than that of the commercial catalyst. The results show that OGCB has a promising application prospect in the field of proton exchange membrane fuel cell(PEMFC)catalyst support.