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同时控制纳米贵金属颗粒的形状(表面原子结构)和成分对进一步提升其性能具有重要意义.针对铂铱合金纳米颗粒,已有研究发现铱原子的引入会降低铂基合金纳米颗粒在一些体系中的催化活性.本文首次制备了具有(100)择优晶面的铂铱立方体纳米颗粒,并在一(100)敏感的模型反应(即氨的电催化氧化反应)中,发现其特殊的高催化活性.所制备的铂铱立方体纳米颗粒具有规则的(100)晶面特征,并伴随有晶格收缩现象,此外铂和铱存在电子交互作用.铂铱立方体纳米颗粒的特定催化活性高于纯铂纳米颗粒,并远高于普通多晶铂铱纳米颗粒.该现象一方面可归因于具有高催化活性的铂(100)活性点,另一方面可归因于铱和铂的协同效应.以上研究结果表明,在铂基合金纳米颗粒形状可控的前提下,引入铱原子可进一步提升其催化活性,这对于发展具有高催化活性的贵金属纳米颗粒具有一定的指导意义.
At the same time it is important to control the shape (surface atomic structure) and composition of nano-precious metal particles to further enhance their performance.For the platinum-iridium alloy nanoparticles, it has been found that the introduction of iridium atoms will reduce the platinum-based alloy nanoparticles in some systems Catalytic activity.The platinum-iridium cubic nanoparticles with (100) preferred crystal facets were prepared for the first time and their special high catalytic activity was found in one (100) sensitive model reaction (ie, the electrocatalytic oxidation of ammonia). The prepared platinum-iridium cubic nanoparticles have a regular (100) crystal plane characteristic accompanied by lattice shrinkage, and furthermore there is an electronic interaction between platinum and iridium. The specific catalytic activity of platinum-iridium cubic nanoparticles is higher than that of pure platinum nanoparticles , And much higher than that of ordinary polycrystalline platinum iridium nanoparticles.This phenomenon can be attributed to the platinum (100) active sites with high catalytic activity on the one hand and the synergistic effect of iridium and platinum on the other hand.The above results It is indicated that the introduction of iridium atom can further enhance its catalytic activity under the premise that the shape of platinum-based alloy nanoparticles can be controlled, which is of great significance for the development of noble metal nanoparticles with high catalytic activity Have some guiding significance.