State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, Jilin China.
University of Chinese Academy of Sciences , Beijing 100039, China.
ACS Appl Mater Interfaces. 2017 Sep 6;9(35):29623-29632. doi: 10.1021/acsami.7b04489. Epub 2017 Aug 25.
PtNi nanoparticles have been proved to be a type of highly efficient electrocatalyst for the oxygen reduction reaction (ORR) among the Pt-based nanomaterials. However, how to improve the surface catalytic activity and stability of polymer-stabilized Pt-based nanocrystals is still a critical issue for their application in fuel cells. In this work, a one-step solvothermal process was used to synthesize PVP-stabilized PtNi nanocubes supported on hollow carbon spheres. With optimized metal precursor ratio (Pt/Ni = 1:1) and solvothermal temperature (130 °C), PtNi nanocrystals with uniform size and cubic shape can be synthesized and highly dispersed on hollow carbon spheres. To improve the electrocatalytic activity of the PtNi nanocrystals, the synthesized composite was treated by a heating annealing at 300 °C and a subsequent electrochemical CO stripping process. It was found that the two-step treatment can significantly enhance the catalytic activity of the PtNi nanocrystals for ORR with high durability. In addition, the prepared PtNi composite also showed higher catalytic activity and stability for methanol oxidation. The obtained peak current density on the present catalyst can reach 3.89 A/mg, which is 9 times as high as commercial Pt/C (0.43 A/mg). The present study not only demonstrates a general method to synthesize hollow carbon sphere-supported nanoparticle catalysts but also provides an efficient strategy to active the surface activity of nanoparticles.
PtNi 纳米颗粒已被证明是一类高效的氧还原反应（ORR）电催化剂，在 Pt 基纳米材料中。然而，如何提高聚合物稳定的 Pt 基纳米晶体的表面催化活性和稳定性，仍是其在燃料电池中应用的关键问题。在这项工作中，采用一步溶剂热法合成了负载在空心碳球上的 PVP 稳定的 PtNi 纳米立方体。通过优化金属前驱体比例（Pt/Ni=1:1）和溶剂热温度（130°C），可以合成出尺寸均匀、呈立方体形的 PtNi 纳米晶体，并高度分散在空心碳球上。为了提高 PtNi 纳米晶体的电催化活性，对合成的复合材料进行了 300°C 的热处理和随后的电化学 CO 剥离处理。研究发现，两步处理可以显著提高 PtNi 纳米晶体对 ORR 的催化活性，且具有高耐久性。此外，所制备的 PtNi 复合材料在甲醇氧化反应中也表现出更高的催化活性和稳定性。在本催化剂上获得的峰值电流密度可达 3.89 A/mg，是商业 Pt/C（0.43 A/mg）的 9 倍。本研究不仅展示了一种合成空心碳球负载纳米颗粒催化剂的通用方法，还提供了一种有效提高纳米颗粒表面活性的策略。
