Atomistic Understanding on the Origin of High Oxygen Reduction Electrocatalytic Activity of Cuboctahedral Pt3Co-Pt Core-Shell Nanoparticles

This time, we report the synthesis of truncated cuboctahedral Pt3Co-Pt core-shell nanoparticles. These nanoparticles are composed of a complete Pt monolayer skin, followed by layers with a ~78 At% of Pt, in a Pt3Co configuration, and finally a Co rich core with just 64 At% of Pt. This specific configuration exhibit an electrocatalytic activity ~6 times higher than commercial 30%-Pt/Vulcan. This work has been published in the Journal of Catalysis Science & Technology, and can be downloaded here.

Guangzhi Hu, Eduardo Gracia-Espino, Robin Sandström, Tiva Sharifi, Shaodong Cheng, Hangjia Shen, Chuanyi Wang, Shaojun Guo, Guang Yang, Thomas Wågberg.

Catal. Sci.Technol., 2015, DOI: 10.1039/C5CY01128K

Abstract

PtM-based core-shell nanoparticles are a new class of active and stable nanocatalysts to promote oxygen reduction reaction (ORR), however, the understanding at atomistic level of their high electrocatalytic performance for ORR is still a great challenge. Herein, we report a synthesis of highly ordered, and homogeneous truncated cuboctahedral Pt3Co-Pt core-shell nanoparticles (cs-Pt3Co). By combining atomic resolution electron microscopy, X-ray photoelectron spectroscopy, extensive first-principles calculations, and many other characterization techniques, we conclude that the cs-Pt3Co nanoparticles are composed of a complete or nearly complete Pt monolayer skin, followed by a secondary shell containing 5-6 layers with a ~78 At% of Pt, in a Pt3Co configuration, and finally a Co rich core with 64 At% of Pt. Only this particular structure is consistent with the very high electrocatalytic activity of cs-Pt3Co nanoparticles for ORR, which is about 6 times higher than commercial 30%-Pt/Vulcan, and 5 times more active than non-faceted (spherical) alloy Pt3Co nanoparticles. Our study gives an important insight into the atomistic design and understanding of advanced bimetallic nanoparticles for ORR catalysis and other important industrial catalytic applications.