高质量和深度凹陷的PtPdNi纳米立方体作为高效氧还原反应的催化剂

High-quality and deeply excavated PtPdNi nanocubes as efficient catalysts toward oxygen reduction reaction

聚合物电解质燃料电池阴极上的氧还原反应需要使用铂基催化剂,铂是地球上的贵金属之一.采用将不同的金属优化到核心中等多种策略可提高铂基催化剂的活性,从而降低铂的负载量.通过致力于高催化活性Pt_(2.7)Pd_(0.3)Ni凹面立方结构与高指数晶面的复合,表明凹面结构可以提供更多的活性位和高水平的催化活性,如果与其他金属复合,可以降低铂的比例,提高其质量活性.本文采用一锅法合成了PtPdNi凹立方体结构,并发现DMF和油胺的比例是影响PtPdNi凹陷程度的主要因素.通过对PtPdNi凹立方体的形态和组成进行详细表征,研究了PtPdNi凹立方体的形成机理,认为十六烷基三甲基溴化铵、油酸胺和二甲基甲酰胺的比例在PtPdNi凹立方体的合成中起着关键作用.本文还对Pt_(2.7)Pd_(0.3)Ni凹立方结构形成的理论和条件进行了探讨,并通过改变反应条件,考察了其所表现出的差异.电化学测试的氧还原性能结果表明,凹面立方体形状的PtPdNi催化剂在0.9 V下的质量活性为1.28 mg_(Pt)^(–1),最高质量活性和比活性分别是市售铂炭的8.20倍和8.68倍.铂钯镍三元纳米笼具有优异的结构稳定性,经稳定性测试,纳米结构没有明显的变化和性能退化.PtPdNi凹立方体对阴极具有很高的电催化活性和稳定性,燃料电池的氧还原反应由于高凹度、高空间利用率和PtPdNi凹立方体丰富的高指数表面以及PtPdNi之间的协同效应,为进一步控制铂基纳米催化剂的合成提供更多的思路和方法及未来工业应用的不同形态和结构.

The oxygen reduction reaction(ORR)on the cathode of a polymer electrolyte fuel cell requires the use of a catalyst based on Pt,one of the most expensive metals on the earth.A number of strategies,including optimization of a different metal into the core,have been investigated to enhance the activity of a Pt-based catalyst and thus reduce the loading of Pt.By dedicating to compounding high catalytic activity Pt_(2.7)Pd_(0.3)Ni concave cubic with high index crystal face,the paper shows that concave structures can offer more active site and high level of catalytic activity and if mixed with other metal,decrease the proportion of Pt and improve its mass activity.The paper also makes an exploration into the theory and conditions behind the formation of Pt_(2.7)Pd_(0.3)Ni concave cubic structure,and investigates the difference it demonstrates by modifying the reactive conditions.The results of the oxygen reduction performance of the electrochemical test are as follows:the concave cube-shaped Pt-Pd-Ni catalyst has a mass activity of 1.28 A mg_(Pt)^(–1) at 0.9 V,its highest mass activity is 8.20 times that of commercial Pt/C,and its specific activity is 8.68 times of that commercial Pt/C.And the Pt-Pd-Ni ternary nanocage has excellent structural invariance.After the stability test,there is no obvious structural change and performance degradation in the nanostructure.