Co-Fe-Pd纳米粒子的可控制备及其氧还原催化性能

以Co(COOH)₂、FeCl₃和PdCl₂为原料，柠檬酸为稳定剂，乙醇为加速剂，采用超声辅助制备Co-Fe-Pd金属纳米粒子，并评估其氧还原反应(ORR)电催化性能。研究结果表明，Co-Fe-Pd金属纳米粒子平均粒径约3～5 nm，由于Co、Fe固溶于Pd晶格，使Co-Pd、Fe-Pd和Co-Fe-Pd纳米粒子仅显示Pd衍射峰，且伴有不同程度的宽化；相比于Co-Fe、Fe-Pd或Co-Pd纳米粒子，三元Co-Fe-Pd晶格压缩更为明显，晶格缺陷诱使的活性位点增加，氧还原催化能力增强；其氧还原起峰电位为1.03 V(vs RHE)，Tafel斜率为?87 mV/dec,可与商用Pt/C催化剂相媲美；氧还原过程中电子转移数为3.80±0.04，说明其主导四电子转移路径；此外，RRDE结果显示氧还原过程中的中间产物H₂O₂含量约10%。

Controllable preparation of Co-Fe-Pd nanoparticles and their catalytic activities toward oxygen reduction

Co(FeOH)₂, FeCl₃ and PdCl₂ were used as raw materials, citric acid was used as stabilizer, and ethanol was used as accelerator. Ultrasonic-assisted preparation of Co-Fe-Pd metal nanoparticles was carried out, and the oxygen reduction reaction (ORR) electrocatalytic performance was evaluated. The results show that the average size of Co-Fe-Pd nanoparticles prepared by ultrasonic method is about 3—5 nm, and only Pd diffraction peaks are detected for the Co-Pd，Fe-Pd and Co-Fe-Pd nanoparticles because of the dissolution of Co and Fe into the Pd lattice. Compared to Co, Co-Fe Fe-Pd and Co-Pd nanoparticles, the lattice contraction of Co-Fe-Pd nanoparticles exhibited as the wide peaks is remarkable, which leads to increasing lattice defects and subsequent enhanced catalytic activities. The onset potential of oxygen reduction and the slop of Tafel for the Co-Fe-Pd nanoparticles are 1.03 V(vs RHE) and -87 mV/dec, respectively. The values obtained here are comparable to those of commercial Pt/C catalyst. The transferred electron-number of Co-Fe-Pd nanoparticles is 3.80±0.04 during the oxygen reduction, which is dominated by a four-electron pathway. Furthermore, the peroxide percentage (H₂O₂) is about 10% from the results of RRDE.