Jang Ji-Hoon, Lee Eunjik, Park Jinwoo, Kim Gunn, Hong Suklyun, Kwon Young-Uk
Department of Chemistry, HRD Center for Creative Convergence Chemical Sciences, SAINT/Center for Human Interface Nano Technology, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Sci Rep. 2013 Oct 7;3:2872. doi: 10.1038/srep02872.
We report on the syntheses of core-shell Fex@Pt (x=0.4-1.2) nanoparticles (NPs) with Pt-shell thickness systematically controlled while the overall particle size is constant. The syntheses were achieved via one-pot ultrasound-assisted polyol synthesis (UPS) reactions. Fe1.2@Pt showed a record-breaking high core-element content (55 at%) of core-shell NPs. Based on observations from a series of control experiments, we propose a mechanism of the NPs' formation that enables control of shell thickness in UPS reactions. Fex@Pt NPs showed drastic enhancements in mass and specific activity for oxygen reduction reaction (ORR) and significantly enhanced durability compared to commercial Pt NPs. Fex@Pt with a 1 (monolayer) ML Pt shell showed the highest activity. The ab initio density functional theory calculations on the binding energies of oxygen species on the surfaces of Fex@Pt NPs showed that the 1 ML case is most favourable for the ORR, and in good agreement with the experimental results.
我们报道了核壳结构的Fex@Pt（x = 0.4 - 1.2）纳米颗粒（NPs）的合成，其中Pt壳层厚度得到系统控制，而整体颗粒尺寸保持恒定。合成是通过一锅法超声辅助多元醇合成（UPS）反应实现的。Fe1.2@Pt显示出核壳纳米颗粒创纪录的高核元素含量（55原子%）。基于一系列对照实验的观察结果，我们提出了一种纳米颗粒形成机制，该机制能够在UPS反应中控制壳层厚度。与商业Pt纳米颗粒相比，Fex@Pt纳米颗粒在氧还原反应（ORR）的质量活性和比活性方面有显著提高，并且耐久性显著增强。具有1（单层）ML Pt壳层的Fex@Pt表现出最高活性。对Fex@Pt纳米颗粒表面氧物种结合能的从头算密度泛函理论计算表明，1 ML的情况对ORR最为有利，与实验结果吻合良好。
