Improved photocatalytic activity of surface charge functionalized ZnO nanoparticles using aniline

Functionalization of aniline molecules on zinc oxide (ZnO) nanoparticles is reported using a simple impregnation technique. Functionalized ZnO samples were systematically characterized based on morphology, surface and optical properties, and photocatalytic performance towards methyl orange (MO). Aniline functionalization increased the surface charge of the modified ZnO. Compared to pristine ZnO, the aniline-functionalized ZnO yielded faster photodegradation of MO, degrading 98.29 % of MO in 60 min and superoxide radicals were the major species during the MO photodegradation reaction. These results indicate that the improvement of photocatalytic degradation could be attributed to opposite charge-induced surface adsorption. Hence, protonated amine as a positively charged molecule was expected to increase the surface adsorption of MO (as an anionic dye) on ZnO nanoparticles surfaces, thereby increasing their photocatalytic degradation performance.