Flexible laser-induced graphene (LIG)/ZnO-nanorod (NR) heterostructure for efficient photodegradation

In this work, a flexible laser-induced graphene (LIG)/ZnO nanorod heterostructure was developed for the photocatalytic degradation of methylene blue (MB) under UV exposure. Oxygen plasma treatment was employed to alter the LIG surface wettability from hydrophobic to hydrophilic, thus facilitating the uniform deposition of ZnO nanorods on the LIG substrate. The successful formation of crystalline ZnO nanorods on the LIG surface was confirmed using X-ray diffraction and SEM studies. Photocatalytic performance studies were performed under UV light for 120 minutes. Among the developed composites, the LIG/ZnO10 composite exhibited the highest degradation rate of 96.7%. The high rate of degradation was maintained over multiple cycles, thus further accentuating the stability of the developed composites for real-world application. This enhanced photocatalytic activity can be ascribed to enhanced dye adsorption, increased interfacial LIG/ZnO contact and more effective charge separation and transportation. To validate the porous nature of the synthesized LIG, BET surface area analysis was performed, which identified abundant active sites for dye adsorption and enhanced photocatalytic degradation. The reaction mechanism was validated using radical scavenging experiments. These results suggest that oxygen plasma surface engineering is an efficient technique for increasing the performance of LIG-based photocatalysts and highlight the potential of flexible LIG/ZnO heterostructures for dye degradation applications.