Enhanced oxygen reduction reaction activity by utilizing carbon nanotube intramolecular junctions

Abstract

DFT calculations are performed to study the enhanced oxygen reduction reaction (ORR) activity by utilizing carbon nanotube intramolecular junctions (IMJs). The obtained results suggest that the adsorption of ORR species on the basal carbon of the pristine nanotubes (armchair and zigzag structures) is too weak, but significant enhancement of adsorption energy could be found on the same position of two types of typical IMJ structures (straight and bent junctions), with the values closer to Pt(111). Furthermore, ORR curves catalyzed by two IMJs all become downhill in the relative energy diagram, suggesting the spontaneous nature of the catalytic process. These obtained results indicate that IMJs possess higher catalytic activity towards ORR. Total electron density and deformation electron density analysis reveal that the improved adsorption of ORR species could be caused the electrostatic interaction between the adsorbed ORR species and IMJs, where the electrons transfer from the latter to the former.