Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, China.
Phys Chem Chem Phys. 2014 Feb 28;16(8):3593-602. doi: 10.1039/c3cp54600d.
The design of amorphous noble metallic nanoparticle electrocatalysts is an important fundamental and applied research challenge because their surface is rich in low-coordination sites and defects which could act as the active sites in various catalytic processes. Here we describe new findings on the amorphous platinum-nickel-phosphorous nanoparticles supported on carbon black (PtNiP(a)/C) and the comparison between their catalytic activity and that of the nanoscale crystalline and phase-segregated PtNiP nanoparticles. The nanoscale amorphous, crystalline and phase-segregated catalysts were probed as a function of surface composition, particle size, and thermal treatment conditions using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, selected area electron diffraction and electrochemical characterization. The results provide the experimental evidence in support of nanoscale amorphous, crystalline, and phase-segregated PtNiP nanoparticles evolution dependence on the catalyst synthesis temperature. More importantly, the results of the electrochemical performance investigation showed that the amorphous structure has not only better catalytic activity for methanol oxidation but also stronger tolerance to carbon monoxide poisoning compared to the crystalline and phase-segregated structure. Besides, the thermal control of the formation of nanoscale amorphous, crystalline and phase-segregated structured catalysts provided the opportunity for establishing the correlation between the nanoscale phase structures of the catalysts and their electrocatalytic activity in methanol oxidation reaction, which plays an important role in developing highly active electrocatalysts for direct methanol fuel cells.
非晶态贵金属纳米粒子电催化剂的设计是一项重要的基础和应用研究挑战，因为它们的表面富含低配位位点和缺陷，这些位点和缺陷可以作为各种催化过程中的活性位点。在这里，我们描述了关于负载在炭黑上的非晶态铂-镍-磷纳米粒子（PtNiP(a)/C）的新发现，并比较了它们的催化活性与纳米级晶态和相分离的 PtNiP 纳米粒子的催化活性。使用 X 射线衍射、X 射线光电子能谱、透射电子显微镜、选区电子衍射和电化学特性研究了纳米级非晶态、晶态和相分离催化剂作为表面组成、颗粒大小和热处理条件的函数。结果提供了实验证据，支持纳米级非晶态、晶态和相分离 PtNiP 纳米粒子的演化取决于催化剂合成温度。更重要的是，电化学性能研究的结果表明，与晶态和相分离结构相比，非晶态结构不仅对甲醇氧化具有更好的催化活性，而且对一氧化碳中毒具有更强的耐受性。此外，纳米级非晶态、晶态和相分离结构催化剂的形成的热控制为建立催化剂的纳米级相结构与其在甲醇氧化反应中的电催化活性之间的相关性提供了机会，这对于开发用于直接甲醇燃料电池的高活性电催化剂具有重要意义。
