Fe-TiO 2 @graphene composite for visible-light-driven photocatalytic methylene blue degradation

Here, we report a Fe-TiO2@rGO composite that exhibits good photocatalytic activity, reusability, non-hazardous properties, and enhanced stability. The wide band gap range of TiO2 (3.2 eV) has been reduced by doping with iron metal oxide nanocomposites and by using a non-metal supporting material, reduced graphene oxide. The photocatalytic and optoelectronic properties of the samples have been analyzed using ultraviolet-differential reflectance spectroscopy (UV-DRS) and photoluminescence (PL) techniques. It has been found that there is a decrease in the band gap (red shift) when we go from bare TiO2 (3.10 eV) to Fe-doped TiO2 (2.65 eV) and the composite (2.15 eV), which indicates the superior absorption capability of the composite over a wider range of the visible spectrum. Furthermore, the photocatalytic degradation study of methylene blue (MB) yields an intriguing result, where the composite shows approximately 85% dye degradation activity within the first 90 minutes, compared to bare TiO2 (25%) and Fe-doped TiO2 (50%). Methylene blue in the proximity of the catalyst surface increases the electron lifetime by reducing the recombination of hole scavengers, allowing the electron to participate in photocatalytic reactions. The formation of radicals, such as hydroxide (OH-) and superoxide (O2-), triggers the decolourization of the methylene blue pollutant.