采用模板法制备了卟啉化合物Meso-5,10,15,20-四(N,N-二甲氨基苯基)卟啉铁(Ⅱ)(TDMNPPFe(Ⅱ)),用活性碳固载、活化制成催化剂。用TEM、XRD对催化剂的微观形貌进行了表征,结果表明,TDMNPPFe(Ⅱ)均匀分散在活性碳表面,当活化温度高于950℃时,催化剂表面开始出现金属原子簇结构的晶体。利用旋转圆盘电极表征了TDMNPPFe(Ⅱ)的催化氧还原活性,考察了活化温度、Fe(Ⅱ)载量对催化活性的影响。结果表明,最佳活化温度为600℃,最佳Fe(Ⅱ)载量为6%(质量分数)。把600℃活化的6%载量的催化剂(Catmax)与Pt/C(ω=30%)作了比较,结果表明Catmax比Pt/C催化剂氧还原起始电位负约90mV,但反应电子转移数相差不大。利用循环伏安法和线性伏安法测试了Catmax催化剂的耐甲醇性能,结果表明,甲醇的加入对催化剂的催化氧还原行为没有任何影响,表明TDMNPPFe(Ⅱ)具有良好的耐甲醇性能。
Meso-5, 10, 15, 20-tetra (N, N-dimethylaminophenyl) porphyrin Fe ( II ) [TDMNPPFe ( II )] were synthesized by one pot method of mixed solvents (propionic acid, acetic acid and nitrobenzene), using Fe( II ) as template. It was adsorbed on the VulcanXC-72 carbon with different proportion and then heat-treated on temperature from 400 ℃ to 1 050 ℃. They were characterized by TEM and XRD, and the result shows that TDMNPPFe ( II ) was adsorbed on the surface of the VulcanXC-72 carbon homogeneously. XRD spectra shows metal crystalline species appears when heat-treated beyond 950 ℃. The catalytic reduction behavior of TDMNPPFe ( II ) catalyst modified on the glass carbon electrode. Using RDE, their electrocatalytic performance for oxygen reduction was investigated by linear voltammetry in O2 satured 0.5 mol/L H2SO4. The influences of activation temperature and Fe ( II ) Ioadings were investigated by K-L curves. The result indicates that TDMNPPFe ( II ) catalysts shows best electrocatalysts capability when heat treat at 600 ℃, and with 6% Fe ( II ) Ioadings (Catmax). Compared Catmax with Pt/C (ω=30%), the original reduction potential was approximately negative 90 mV than Pt/C, but the number of electrons transferred per oxygen molecule were 3.82, similarly with Pt/C. This indicates that almost all the oxygen molecule was reduced to water. The effect of methanol was investigated by means of the cyclic voltammetry and linear voltammetry. The result indicates that Pt/C has two oxidation apices of methanol but TDMNPPFe( II ) catalyst does not. The oxygen reduction curves with or without methanol showed that methanol has no effect with the oxygen reduction reaction. So the TDMNPPFe( II ) catalyst was methanol-tolerant.