摘要
利用电沉积法直接在碳纸上制备了一系列钯金二元金属纳米催化剂。用场发射扫描电镜(FESEM)和X射线能谱(EDX)对催化剂的形貌、结构和组成进行了测试和分析,发现所沉积的颗粒基本为球形,粒径分布比较均匀,约为80 nm,钯和金基本按配比沉积。在碱性条件下研究了催化剂对甲醇的催化性能,结果表明所制备的二元催化剂对甲醇的氧化能力均大于一元催化剂。且当钯与金原子比为1∶1时,所制备的Pd1Au1催化剂对甲醇具有最高的催化活性和最好的稳定性。这种催化增强作用主要应归于钯金之间的协同效应,即金元素的存在可以帮助有效去除吸附在钯元素表面的CO,减小CO对催化剂的毒化作用。但第二种金属元素的引入量必须在一个合适的范围,才能最好地利用这种协同效应,使催化性能达到最佳。这种利用电沉积法直接在碳纸上制备二元纳米催化剂的方法,可以有效简化传统直接甲醇燃料电池(DMFC)中制作膜电极的复杂工艺过程,具有极大的应用价值。
Pd and Au binary metal nano-catalysts with different molar ratios were directly synthesized on carbon papers by an electro- deposition method. The morphology, structure and element composition were detected by field emission scanning electron microscopy （FESEM） and energy dispersive X-ray spectrum （EDX）. It was found that the as-deposited particles were all ball-shaped and the dis- tribution of the particle sizes was very uniform within a size range of - 80 nm. The molar ratios of Pd and Au elements in the particles were very close to the molar ratios of initial solution. The catalytic behaviors for methanol oxidation of the as-prepared catalysts were in- vestigated in alkaline environments. The results indicated that all the binary-metal catalysts had better catalytic activities than the unita- ry-metal catalysts. When the molar ratio of the initial solution was 1 ： 1, the as-obtained Pd1AuI nano-catalyst showed the highest cata- lytic activity and the best stability. The catalytic enhancement phenomena were mainly due to the synergistic effect between the two dif- ferent metal elements. The Au elements could effectively remove the adsorbed CO on the Pd surfaces, and therefore reduced the CO poisoning effect. But the additive amount of the second metal elemeut must be in a specific range so that the synergistic effect could be fully utilized to generate the best catalytic performance. The way to directly deposit binary metal nano-catalysts on carbon papers by electrodeposition could simplify the process for preparing membrane electrode assembly in traditional direct methanol fuel cell （DMFC） and possessed a significant application potential.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2015年第6期493-497,共5页
Chinese Journal of Rare Metals
基金
国家自然科学基金项目(51203093
51204094
51374125)
高校杰出青年学者成长计划项目(LZQ2013031)
辽宁省博士科研启动基金项目(20141122)
辽宁省大学生创新创业项目(201310146001)资助
