Photocatalytic Performance of Titanium Dioxide Nanoparticles Doped with Multi-metals

Metal-doping is an efficient approach to improve the performance of catalysts, but few researches have been done in applying mixed metals as dopant due to heavy jobs and complex results. In this study, we prepared and evaluated a group of 3-metal-doped nano-TiO2 composite photocatalyst (M-1-M-2-M-3/TiO2, M = Cu(II), Mn(II), Zn(II), Co(II), Ni(III), Bi(III)). The prepared catalysts were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of the catalysts were evaluated by the degradation of methyl orange (MO) under UV-irradiation. The results showed that Bi-Mn-Zn/TiO2 photocatalysts (containing 1.65, 0.41, 0.47 wt% of Bi, Mn, Zn respectively) exhibited the highest removal efficiency (R-t) of 27% for adsorption of MO after 1h in dark and superior photocatalytic activity for degradation of MO, with the highest R-t of 93.03% among all samples after 15 min UV-irradiation. The photocatalytic enhancement of Bi-Mn-Zn/TiO2 was attributed to its unique semiconductor composite structure: Bi2O3-MnO-ZnO-TiO2 and further proved in batch experiments. Importantly, the as-synthesized M-1-M-2-M-3/TiO2 remains stable during the photocatalytic reaction and can be used repeatedly, revealing their promising application in the treatment of organic wastewater.