Morphology and surface engineering of vertical graphene films for dye photodegradation

It has been reported that vertical graphene (VG) has the capability to be a photocatalyst. In previous studies, the morphology evolution of the VG films synthesized by the plasma-enhanced chemical vapor deposition (PECVD) process has been investigated. This work focuses on the impact of the morphologies of the VG films on photocatalytic properties. Three morphologies of the VG films, VG with porous graphene (VG-P), ‘forest-like’ graphene (VG-F), and ‘wall-like’ vertical graphene (VG-W), are fabricated and the photodegradation properties are investigated. In order to enhance the photodegradation property of the VG films, the surface of the VG films with different morphologies is treated with oxygen plasma, in which the oxygen plasma treated VG-P, VG-F, and VG-W are named as VG-P-O, VG-F-O, and VG-W-O, respectively. As a result, the VG-P-O shows the best degradation performance of 82.6% for methylene blue and 86.7% for methyl orange, which is attributed to the desirable porous structure and the modified hydrophilicity.