Selective Deposition of Co3O4 on TiO2 001 Crystal Surface and Its Photocatalytic Activity

The photocatalytic activity of TiO₂ nanoparticle is highly depends on the exposure ratio of its 001 crystal facets, but many of the synthetic routes tend to use fluorochemicals as the control agents, which were usually cancerigenic and may decrease the photocatalytic activity of TiO₂. Therefore, a fluorine-free route was adopted by using potassium titanate nanowires and（NH₄）₂CO₃ as precursors and morphology control agent, respectively, to control the exposure ratio of TiO₂ 001 and 101 crystal faces by varying the concentration of（NH₄）₂CO₃. Then Co₃O₄ was selectively deposited on the 001 surface of TiO₂ to further promote the separation of photogenerated electrons and holes. The photocatalytic degradation efficiency of rhodamine B was investigated. The study shows that the optimum exposure ratio of TiO₂001 and 101 crystal surfaces is about 1∶9, the optimum deposition amount of Co₃O₄ is about 0.018%, and the photodegradation activity is 3.5 times that of commercial P25.