Photocatalytic degradation of malachite green using hydrothermally synthesized cobalt-doped TiO2 nanoparticles

Simple and time efficient hydrothermal method was employed to obtain phase pure anatase TiO2 and Co2+-TiO2 nanoparticles (NPs) as an efficient visible light active photocatalyst. The phase purity, morphology, optical property, and compositions were confirmed by various characterization techniques. The XRD analysis confirms the polycrystalline nature for Co2+-TiO2 photocatalyst. Raman peaks at 398, 516.89 and 640 cm−1 affirmed anatase Co2+-TiO2 NPs and XPS analysis reveals substitution of Ti4+ with Co2+ ions in TiO2 NPs. The 1.61 wt.% Co2+-TiO2 NPs has bandgap value of 2.95 eV which specifies the efficiency of material for the absorption of visible light. The obtained TiO2 and Co2+-TiO2 materials were explored for photocatalytic degradation of MG under UV, visible and direct sunlight. The removal of MG was confirmed using COD analysis. The obtained visible light active (1.61 wt.%) Co2+-TiO2 showed 82% removal of MG under direct sunlight.