采用两步沉积还原法制备了一种以PdRu合金为核、以铂为壳,以碳纳米管(CNT)为载体的核壳结构低铂催化剂PdRu@Pt/CNT.该催化剂对于甲醇催化氧化的单位质量铂的活性可达自制20％ Pt/CNT催化剂的1.7倍,且其正扫和反扫峰的峰电流密度之比((Ⅰ)f(/Ⅰ)b)高达2,是Pt/CNT催化剂(Ⅰf/Ⅰb)值的2倍,表明通过将活性组分铂分散在PdRu核上,有效地提高了金属铂的分散度和铂的利用率,且通过壳层铂原子与核中钌及钯的相互作用,大大提高了催化剂对甲醇氧化中间体的去除能力.X射线衍射(XRD)和透射电子显微镜(TEM)的结果揭示了催化剂的核壳结构.另外,从TEM还可以看出:活性组分均匀地分布在碳纳米管载体上,活性组分粒径约为4.0 nm.由于这种催化剂能够有效提高铂的利用效率,并且有效消除甲醇氧化中间体,在低温燃料电池领域具有良好的应用前景.%We prepared a low Pt loading core-shell structured catalyst PdRu@Pt/CNT (carbon nanotube) with a PdRu alloy as the core and platinum as the shell in addition to carbon nanotubes as supports in a two-stage precipitation-reduction approach. For the anodic oxidation of methanol the activity in terms of Pt loading increased by 70% compared with the lab-made Pt/CNT catalyst and the ratio of the forward current density (I,) to the backward current density (/b) was as high as 2, which is two times of that of Pt/ CNT, indicating that the dispersion and use of platinum effectively improves by covering the surface of the PdRu cores with platinum. Excellent tolerance towards the intermediates of the anodic oxidation of methanol may result from the interaction between the Pt shell and the PdRu core. The core-shell structure of the catalysts was revealed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM image showed that the active components are highly dispersed on the CNT with a particle size of 4.0 nm. The high platinum utilization and high performance as well as good tolerance toward poisons make the PdRu@Pt/CNT catalyst a promising low-Pt catalyst for low temperature fuel cell applications.
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