Leteba Gerard M, George Sarah L, Mitchell David R G, Levecque Pieter B J, van Steen Eric, Macheli Lebohang, Lang Candace I
Centre for Materials Engineering, Department of Mechanical Engineering, University of Cape Town, Cape Town, 7700, South Africa.
Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Cape Town, 7700, South Africa.
Chempluschem. 2024 Jul;89(7):e202400083. doi: 10.1002/cplu.202400083. Epub 2024 Apr 19.
We report the synthesis of core-shell Ni-Pt nanoparticles (NPs) with varying degrees of crystallographic facets and surface layers rich in Pt via a seed-mediated thermolytic approach. Mixtures of different surfactants used during synthesis resulted in preferential surface passivation, which in turn dictated the size, chemical composition, and geometric evolution of these PtNi NPs. Electrochemical investigations of these pristine core-shell Ni-Pt structures in the oxygen reduction reaction (ORR) show that their catalytic functionalities outperform the commercial Pt/C reference catalyst. The enhanced electrocatalytic ORR performances of these Pt-based PtNi NPs are correlated with the weakened oxygen binding strength or surface-adsorbed hydroxyl (OH) species on active Pt surface sites induced by the downshift of the d-band center as a result of compressive strain effects. Our studies offer a robust synthetic approach for the development of core-shell nanostructures for enhanced ORR catalysis.
我们报道了通过种子介导的热解方法合成具有不同程度结晶面和富含Pt的表面层的核壳Ni-Pt纳米颗粒（NPs）。合成过程中使用的不同表面活性剂混合物导致优先表面钝化，这反过来又决定了这些PtNi NPs的尺寸、化学成分和几何演变。对这些原始核壳Ni-Pt结构在氧还原反应（ORR）中的电化学研究表明，它们的催化功能优于商业Pt/C参考催化剂。这些基于Pt的PtNi NPs增强的电催化ORR性能与由于压缩应变效应导致的d带中心下移所诱导的活性Pt表面位点上氧结合强度或表面吸附羟基（OH）物种的减弱有关。我们的研究为开发用于增强ORR催化的核壳纳米结构提供了一种可靠的合成方法。
