Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, USA.
J Am Chem Soc. 2010 Feb 24;132(7):2151-3. doi: 10.1021/ja909442c.
Platinum nanoparticle catalysts are essential for achieving energy-efficient and greener chemical processes that involve breaking or establishing of H-H, C-H, or O-H bonds. In this work, we report an innovative top-down strategy to prepare the supported Pt nanoparticles with an average size of approximately 2 nm, starting directly from bulk metallic Pt by metallurgical method. Bulk platinum was dissolved in liquid lithium and ruptured into nanoparticles. This Li-Pt liquid alloy was quenched into Li-Pt solid solution. The lithium content was further converted into LiOH. The resulting powder of Pt nanoparticles in LiOH can be mixed with any nonaqueous support materials. Thereafter, the LiOH can be selectively leached off by water, allowing Pt nanoparticles to be adsorbed on the desired support material. Transmission electron microscope and extended X-ray absorption fine structure analyses demonstrated that the as-formed Pt nanoparticles have an average size of around 2 nm. The carbon-supported Pt nanoparticles prepared by this method inherit more characteristics of their bulk counterparts so that high specific catalytic activity of bulk Pt is maintained, which is confirmed by a preliminary electrocatalytic characterization of oxygen reduction reaction (ORR).
铂纳米颗粒催化剂对于实现节能、更环保的化学过程至关重要，这些过程涉及到 H-H、C-H 或 O-H 键的断裂或形成。在这项工作中，我们报告了一种创新的自上而下的策略，通过冶金方法直接从块状金属铂开始制备平均尺寸约为 2nm 的负载型 Pt 纳米颗粒。块状铂溶解在液态锂中，并通过破裂形成纳米颗粒。这种 Li-Pt 液态合金被淬火成 Li-Pt 固溶体。锂的含量进一步转化为 LiOH。Pt 纳米颗粒在 LiOH 中的所得粉末可以与任何非水载体材料混合。此后，通过水选择性地浸出 LiOH，允许 Pt 纳米颗粒吸附在所需的载体材料上。透射电子显微镜和扩展 X 射线吸收精细结构分析表明，形成的 Pt 纳米颗粒的平均尺寸约为 2nm。通过这种方法制备的碳负载 Pt 纳米颗粒继承了其块状对应物的更多特性，从而保持了块状 Pt 的高比催化活性，这通过初步的氧还原反应（ORR）电催化表征得到了证实。
