Gemini surfactant assisted synthesis of mesoporous Mn/Mg bimetal doped TiO2 nanomaterial: characterization and photocatalytic activity studies under visible light irradiation

The present work mainly aimed to synthesize different weight percentages (0.25–1.00 wt%) of Manganese (Mn 2+ ) and Magnesium (Mg 2+ ) bimetal ions doped TiO 2 nanomaterial assisted with different weight percentages (5–15 wt%) of Gemini surfactant (GS) using sol-gel method. The bimetal doped and undoped TiO 2 photocatalysts were characterized by X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Diffused Reflectance Spectroscopy, Transmission Electron Microscopy, Brunauer-Emmett-Teller surface area analyzer, and Photoluminescence Spectroscopy. Characterization results revealed that mesoporous multi-particle anatase TiO 2 nanoparticles with a narrowed band gap, small particle size, and high surface area were formed due to the combined effect of Mn 2+ /Mg 2+ bimetal ions doping and effective encapsulation of GS over the initially formed TiO 2 nanoparticles. The surface elemental composition of the 0.25 wt% Mn 2+ and 1.00 wt% Mg 2+ bimetal doped TiO 2 in the presence of 10 wt% of GS (after calcination) revealed the presence of both the metal dopants Mn 2+ and Mg 2+ along with the Ti and O and their chemical interactions were further confirmed by FT-IR results. The photocatalytic activity of these catalysts was assessed by the degradation of Methyl Red using visible light irradiation. To understand the effect of different reaction parameters on the photocatalytic activity of the nanocatalysts such as the dopant concentration, surfactant concentration, catalyst dosage, solution pH, and initial dye concentration were investigated and optimized to achieve the best performance. The photoluminescence results conclude that OH radicals are the crucial reactive species responsible for oxidative photocatalytic degradation of Methyl Red.