Realization of Improved Visible Light-Mediated Photocatalytic Activity of Al2O3 Nanoparticles Through Cobalt Doping

Improved photocatalytic activity through cobalt (Co) doping has been reported for Al 2 O 3 nanoparticles in this paper. Undoped and Co-doped Al 2 O 3 nanoparticles have been synthesized via a precipitation method. Pure and Al 2 O 3 nanoparticles exhibit a monoclinic crystal structure. The optical bandgap decreases from 3.80 eV to 3.64 eV with Co doping. Due to the red shift in the bandgap, the recombination rate of photo-induced electrons and holes decreases in the doped catalysts which improved their efficiencies against the degradation of rhodamine dye. A remarkable degradation efficiency of 95.45% is evinced for the 4 wt.% Co-doped Al 2 O 3 catalyst and this was well acknowledged from its decreased crystallite size, decreased bandgap and increased photosensitivity values. An increased degradation rate constant value of 0.96649 min −1 observed for the 4 wt.% Co-doped Al 2 O 3 catalyst also confirms this. The results obtained indicate that the Co-doped Al 2 O 3 nanoparticles are potential candidates as visible light catalysts with remarkable degradation efficiencies against toxic dyes. Also, the realization of ferromagnetism confirms the regenerable and reusable quality of the Co-doped Al 2 O 3 catalysts.