CuO sputtered flexible polyaniline@graphene thin films:A recyclable photocatalyst with enhanced electrical properties

Flexible conducting polymers based thin film substrate sputtered with nanoparticles are novel materials towards photocatalytic applications due to the synergistic effect of polymers and nanomaterials which results in low band gap energy, high visible light harvesting, and ease of repeated usage in comparison to powdered catalysts. Herein, a facile technique was used for the fabrication of free standing conducting film of CuO/graphene@polyaniline (CuO/GN@Parii) by the radio frequency (RF) magnetron sputtering of CuO over GN@Pani film. Nanostructured GN sheets were well dispersed inside the Pani sheets as was evident from the scanning electron microscopy and atomic force microscopy (AFM). The AFM analysis showed the increase in the surface area and total roughness after CuO sputtering. The structural analysis showed the presence of Cu2p, C-Cu interaction and shakeup satellite peak owing to the photoelectron emission from ground state to excited state which is also expected to significantly contribute towards the enhancement of the photocatalytic activity. The CuO/GN@Pani showed enhanced electrical conductivity, stability, and up to 99% photocatalytic degradation of 2-chlorophenol which is credited to the double synergistic effect. The first synergistic effect due to the well dispersed GN in the Pani matrix which increases the conductivity due to its conductive nature. The second synergistic effect arises due to the sputtered CuO over GN@Pani which further helps in the mobility of charge carriers, thereby suppressing the band gap and lowering the charge recombination rate. CuO/GN@Pani film showed high stability under cyclic and isothermal aging conditions and showed the semiconducting nature of the composite films at high temperature with very little degradation of the polymer chains.