Nanosheet-Structured Boron Carbon Nitride Spheres as Stable Electrocatalyst Support for Oxygen Reduction Reaction

Abstract

A novel nanosheet-structured boron carbon nitride spheres (BCNSs) have been prepared for application as electrocatalyst support of oxygen reduction reaction (ORR) for the first time. The BCNSs were prepared by a catalyzed thermal evaporation method from solid B powders. The BCNSs are hollow with the diameter in the range of 450-500 nm and composed of many radially oriented ultrathin nanosheets with a mean thickness of 8.6 nm. Due to immobilization in the spheres the constituting BCN nanosheets are free of agglomeration, capable of preserving high surface area during application. Small Pt nanoparticles with diameters of 2-8 nm were deposited onto the BCNSs by ethylene glycol reduction method. The Pt/BCNSs catalyst shows excellent electrocatalytic performance for ORR with the onset potential at 0.10 V and current retention of 85.4 % after 20 000s, which is superior to the commercial 20 % Pt/C catalyst. The improved electrocatalytic performance of the Pt/BCNSs arises from the unique structure and high chemical stability of the BCNSs support and the possible synergistic effect between Pt and the support. The present work indicates that the BCNSs are excellent electrocatalyst support for ORR, which can be further improved by optimizing the composition and structure.