Visible light photocatalytic activity of novel Ni²⁺, Cu²⁺ and VO₂ complexes derived from vanillin bidentate Schiff base ligand doped on TiO₂ nanoparticles

Abstract

A new bidentate NN-Schiff base ligand of vanillin, (E)-4-(((2-amino-5-nitrophenyl)imino)methyl)-2-methoxyphenol, was synthesized and characterized by different spectroscopic techniques. In addition, mononuclear complexes were synthesized by treating the corresponding metal salts of Ni²⁺, Cu²⁺ and VO₂ and Schiff base ligand in methanol. The resulting complexes were characterized by FT-IR, UV–Vis and ¹H NMR techniques. The hybrids of complex/TiO₂ nanoparticles were prepared and their structure and morphology were characterized by FT-IR, XRD, TEM, SEM and solid state UV–Vis absorption. Furthermore, Kubelka–Munk transformations were used to measure the absorption curves and band gap. The photocatalytic activities of the prepared modified semiconductors were tested under visible radiation for the degradation of methylene blue in the aqueous solution. The results indicated that the incorporation of these complexes improved the activation of TiO₂ with visible light.