Barrier mechanism of nitrogen-doped graphene against atomic oxygen irradiation

Abstract

Nitrogen-doped graphene (NG) exhibited a good activity as an electrocatalyst of oxygen reduction reaction while there was no experimental example to investigate the catalytic ability and barrier performance of the NG to atomic oxygen (AO). Here we explored the effect of AO on the structure and barrier properties of pristine graphene (PG) and NG coated Cu foils. AO with high energy and strong oxidizing capacity reacts with graphene and then the graphitic structures are broken down into smaller parts, leading to the oxidation of underlying Cu. Miraculously, AO irradiation causes little damage of NG films and the oxidation degree of NG coated Cu is significantly reduced than that of PG coated. Density functional theory calculations show NG can catalyze the bonding of adsorbed oxygen atom with a second oxygen atom to form O2. And eventually, O2 molecule moves away from the NG surface and the damage of NG film is slow down.