Dai Yu, Chen Shengli
Faculty of Material Science and Chemistry, China University of Geosciences , Wuhan 430074, China.
ACS Appl Mater Interfaces. 2015 Jan 14;7(1):823-9. doi: 10.1021/am5073029. Epub 2014 Dec 26.
A straightforward one-step spontaneous deposition approach for growth of Pt atomic shell on Au nanoparticles and the superior activity and durability of the resulted Pt-on-Au nanoparticles for the oxygen reduction reaction (ORR) are reported. Transmission electron microscopy, X-ray photoelectron spectroscopy, energy-dispersive spectrometry, and electrochemical measurements indicate that Pt can be spontaneously deposited on Au surface upon simply dispersing carbon-supported Au nanoparticles in PtCl42–-containing solution, without introducing any extraneous reducing agents or any pre/post-treatments. The deposited Pt atoms are uniformly distributed on the surface of Au nanoparticles, with coverage tunable by the concentration of PtCl42– and temperatures. An approximate monolayer of Pt forms at temperature of ca. 80 °C and PtCl42– concentrations of above 10–4 mol/L. The obtained Pt-on-Au core–shell nanoparticles catalyze the ORR with specific and mass activities of Pt that are 3.5 times higher than that of pure Pt nanoparticles. Moreover, they exhibit no visible activity degradation after undergoing long-term oxidization/reduction cycling in O2-saturated acid media, therefore showing great prospect as durable cathode electrocatalysts in proton-exchange membrane fuel cells.
报道了一种在金纳米颗粒上生长铂原子壳层的直接一步自发沉积方法，以及所得金上铂纳米颗粒在氧还原反应（ORR）中优异的活性和耐久性。透射电子显微镜、X射线光电子能谱、能量色散光谱和电化学测量表明，只需将碳载金纳米颗粒分散在含PtCl42–的溶液中，铂就能自发沉积在金表面，无需引入任何额外的还原剂或任何预处理。沉积的铂原子均匀分布在金纳米颗粒表面，覆盖率可通过PtCl42–的浓度和温度进行调节。在约80℃的温度和高于10–4mol/L的PtCl42–浓度下形成近似单层的铂。所获得的金上铂核壳纳米颗粒催化ORR的比活性和质量活性比纯铂纳米颗粒高3.5倍。此外，它们在O2饱和酸性介质中经过长期氧化/还原循环后没有明显的活性下降，因此作为质子交换膜燃料电池中耐用的阴极电催化剂具有很大的前景。
