结构有序化金属间Pt3Co纳米线用于强化电催化氧还原性能

Preparation of Structurally Ordered Intermetallic Pt3Co Nanowires and Electrocatalytic Performance for Oxygen Reduction Reaction

摘要:

氧还原反应(ORR)之于燃料电池,金属空气电池等清洁能源转化装置十分重要,因此设计并合成高效且稳定的阴极氧还原催化剂已是目前热门的发展课题。为了达到精准合成材料,且最大程度地使用铂的目的,我们在此使用多孔氧化铝模板(AAO)进行恒电位沉积,在一定浓度的溶液中合成Pt₃Co一维合金纳米线。随后,合金纳米线在真空环境下进行高温退火,分别在400 ℃和650 ℃转变为无序相和有序相Pt₃Co纳米线并通过结构表征证明其已实现有序化转变。合金催化剂在AAO模板内退火,有效地防止了其在高温环境中产生团聚。通过磷酸和铬酸的溶解,合金纳米线从AAO中释放,并用于电催化氧还原反应测试。正如预期一样,与无序Pt₃Co纳米线和商业Pt/C颗粒相比,有序Pt₃Co纳米线表现出更好的半波电位和质量活性,证实了有序Pt₃Co纳米线在元素分布和晶格结构上的优势。此外,有序和无序Pt₃Co纳米线在经过5000次耐久性循环测试后,仍然比Pt/C颗粒具有更强的稳定性。由此可以看出,有序Pt₃Co纳米线作为一种可接受的,具有潜在商业价值的催化材料,成为未来燃料电池催化剂的备选材料。

Abstract:

_{:In the use of clean energy conversion devices such as fuel cells and metal-air batteries, the oxygen reduction reaction process has proven to be exceedingly crucial. Therefore, the design and synthesis of efficient and stable cathodic oxygen reduction catalysts have been an indispensable task at present. In order to achieve accurate synthesis of materials, and the maximum utilization of platinum, anodic aluminum oxide (AAO) template was used to accurately synthesize bimetallic one-dimensional Pt3Co nanowires in a certain concentration of solution. Subsequently, the alloy nanowires underwent a high-temperature phase transition in the template under vacuum, which effectively prevented material agglomeration. The disordered and ordered Pt3Co nanowires were obtained by phase transition annealing at 400 ℃and 650 ℃ respectively and were confirmed by structural characterizations for order phase transition. As expected, compared to disordered Pt3Co, ordered Pt3Co exhibited better mass activity and half-wave potential, confirming the advantages of ordered bimetal alloy nanowires in composition and structure. After the accelerated durability cycle tests, the ordered and disordered Pt3Co nanowires were still more stable than Pt/Cparticles, indicating the advantage of one-dimensional nanowires. It can be seen that the ordered Pt3Co, as an acceptable catalytic material with potential commercial value, has become alternative materials for future fuel cell catalysts.}