TiO_2 photocatalytic antifungal technique for crops diseases control

摘要

TiO2 and 1%Ce3+-TiO2 prepared by hydrothermal method were characterize d by means of XRD and UV-visible diffusive reflectance spectra(DRS). The results of DRS analysis indicated that the 1%Ce3+-TiO2 catalyst had significant optical absorption in the visible region between 400—450 nm because electrons could be excited from the valence band of TiO2 or cerium oxides to Ce 4f level. To inve stigate the photocatalytic activity of different catalysts for crop fungal disea se control, a series of Quine tests were carried out for cucumber powdery mildew and litchi downy blight control in home-made photocatalytic reactor. The result s showed that TiO2 photocatalysis technique should be effective to inhibit the g rowth of fungal diseases to some extent and P-25 had a higher activity for antif ungal control than home-made TiO2 catalysts. TiO2-A prepared with Ti(SO4)2 is more active to contro l antifungal disease than TiO2-B prepared with TiOSO4 as precursor because the crystalline of TiO2-A was higher than that of TiO2-B. T he antifungal index litchi downy blight control was greatly enhanced by doping 1 % cerium ion. The antifungal index of 1.0%Ce3+-TiO2 was(47.0±4.7)%, (82.2±3.5) %, (100±0.0)% under indoor weaker light, solar light and black light, respectiv ely. The results of field experiments showed that the antifungal index of 1.0%Ce 3+-TiO2 was more than that of P-25. The antifungal index of 1.0%Ce3+-TiO2 was (8 1.7±6.5)%, (67.5±4.7)%, (38.6±1.9)% for litchi downy blight, maize southern l eaf spot, and rice blast, respectively. It was concluded that TiO2 photocatalysi s technique should be an effective way for litchi fungal disease control in prac tice.