Weiping Xiaoa,Sufen Liua, Huolin L. Xinb, and Deili Wanga,*
a, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
b, Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA
* Email: wangdl81125@hust.edu.cn
Carbon-supported Pt-based catalysts have been considered as an ideal catalyst for the oxygen reduction reaction (ORR)1. In this regard, it is of great essential to enhance the utilization efficiency of Pt to reduce the overall fuel cell system cost. Recently, Pd-based nanomaterials as catalysts for ORR have attracted much attention because of their unique properties, such as the similar properties to Pt, and the relatively low cost compared with Pt2,3. Based on this, it is of great significance to design a highly active and stable PdM@Pt core-shell structure nanoparticle with PdM core and ultrathin Pt shell.
Here, carbon supported Pd3V@Pt/C core-shell structure nanoparticle has been systematically synthesized via a simple impregnation-reduction method, followed by a spontaneous displacement of Pt. Electrochemical tests reveal that the half-wave potential of Pd3V@Pt/C shifts positively of 80 mV compared with that of Pd/C and the Pt mass activity of Pd3V@Pt/C improves by factors of 10.9 at 0.80 V relative to that of Pt/C. This can be attributed to the strain arising from the mismatch in lattice constant between the Pd3V core and ultrathin Pt shell. Furthermore, the morphology and elemental composition of the Pd3V@Pt/C nanoparticles before and after potential cycling tests are determined using an aberration-corrected Nion scanning transmission electron microscopy (STEM) equipped with an Enfina electron energy loss spectrometer (EELS). After 10 K potential cycling tests, there is no obvious morphology change, because the Pt-rich shell plays an important role in preventing degradation.
Acknowledgements
This work was supported by the National Natural Science Foundation (21306060, 21573083), the Program for New Century Excellent Talents in Universities of China (NCET-13-0237), the Doctoral Fund of Ministry of Education of China (20130142120039), the Fundamental Research Funds for the Central University (2013TS136, 2014YQ009).
References
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