pi-pi Interaction between self-assembled perylene diimide and 3D graphene for excellent visible-light photocatalytic activity

A three-dimensional (3D) graphene/self-assembled perylene imide (rGO/PDI) aerogel composite has been successfully constructed via a simple low-temperature hydrothermal method in this work. The 3D rGO/PDI composite exhibited superior visible-light photocatalytic performance. The removal rate was respectively 2.46 times and 3.33 times higher than that of PDI in static and dynamic catalytic systems. The satisfactory activity is mainly attributed to the more effective separation of electron-hole pairs. To be specific, the self-assembled PDI nano-fibers and graphene are effectively combined via non-covalent pi-pi interaction. The pi-pi interaction enhances the long-range pi-electrons delocalization and electron coupling effects, which is beneficial for the carrier mobility and the separation of electron-hole pairs. Meanwhile, the three-dimensional structure of graphene provides a fast multidimensional channel for electron transfer and effectively improves the adsorption capacity of PDI due to the large specific surface area. What's more, the rGO/PDI composite exhibits great stability than the pure PDI. Overall, this work provides a new insight into improving the photocatalytic activity of self-assembled organic materials.