Preparation And Photocatalytic Activity Of Nanosized NiFe₂O₄-TiO₂ Composite

Nowadays, the environmental pollution has more and more negative impacts on the quality of our daily life. Researches on efficient materials for environmental protection have been focused in recent years. TiO₂ photocatalyst, which can be used in degradation of many organic molecules, has been studied for about ten years. The disadvantage of TiO₂ plotocatalyst is its visible-activity. The aim of this research is to increase the visible-activity of TiO₂.1. NiFe₂O₄ and TiO₂ powder was prepared using sol-gel and co-deposition method, respectively. The nanosized composite of NiFe₂O₄-TiO₂ was prepared by high temperature sintering of NiFe₂O₄ and TiO₂ nanopowder. The as-synthesized powder is in an average size of 40-50 nm. The XRD result shows that the ratio of anatase to rutile is about 7:3 at the annealing temperature of 600℃.2. For comparison, three organic molecules, methylene blue, methyl orange and phenol were selected to test the effectiveness of the as-prepared NiFe₂O₄-TiO₂ nanosized composite. Photocatalytic related factors such as the composite annealing temperature, ratio of NiFe₂O₄ to TiO₂ in the composite, amount of the composite added in the solution and the pH value of the solution were studied. Results show that response of the NiFe₂O₄-TiO₂ nanosized composite in visible light is improved greatly compared with the pure TiO₂ powder, and the degradation amount of the target organic molecule in NiFe₂O₄-TiO₂ added solution is about 2 times that of pure TiO₂ added solution.