Solution Plasma Synthesis of Boron-Carbon-Nitrogen Catalyst with Controllable Bond Structure
Synthesis of boron-carbon-nitrogen (BCN) nanocarbon with a controllable bond structure for enhanced oxygen reduction reaction (ORR) activity and durability was performed using a new method of discharge in organic solution mixtures named solution plasma process. Using selected precursors a new strategy for the simultaneous synthesis of nanocarbon co-doped with heteroatoms was found. The synergetic effect of N and B in an uncoupling bond state improved the formation of new active sites for the ORR performance by changing the electronic structure of the base carbon. Meanwhile, when B and N are bonded together, the BCN catalyst contributes to a reduced ORR activity by forming a balanced electronic structure in carbon. The BCN nanocarbon with uncoupling bond state exhibits an enhanced ORR activity under alkaline conditions, with onset potential of -0.25 V versus -0.31 V for B/N coupling and 3.4 transferred electrons during the ORR. Although the ORR activity of the B/N uncoupling nanocarbon was not as good as the typical Pt/C, the durability of this synthesized material (15.1 % current decrease after 20000 s of operation) was significantly better than that of the Pt/C catalyst (61. 5 % current drop under the same conditions). After durability test, the increase of the chemical states containing oxygen was higher for Pt/C than B/N uncoupling.