Preparation And Performance Of ZnO Photocatalyst And Al₂O₃/ZnO Composite Photocatalyst

As a photocatalytic material, Zn O has the advantages of no pollution, high catalytic activity and stable performance, it is widely applied to the treatment of dye pollutants. Al2O3 has corrosion resistance, large surface area, strong adsorption, and the composites of Al2O3/Zn O would integrate strong adsorption property and degradation property into itself, which will helping to its photocatalytic performanc.In this paper, the synthesis of Zn O photocatalyst and Al2O3/Zn O composite photocatalyst were studied, and characterized by the means of FE-SEM, TEM, EDS, XRD, FT-IR, TG-DTA and low temperature N2 adsorption. Meanwhile, the photocatalytic properties of samples were envaluated by degradation of rhodamine B solution, the results are shown as follows:Zn O photocatalyst with wurtzite structure can be prepared by three different microemulsion system of DBS(CTAB or OP-10)/hexanol/cyclohexane/zinc nitrate solution, at the same time, identify the suitable systhetic conditions of three system. Zn O catalyst systhesized by anionic microemulsion system have regular shape, smaller particle size, large surface area, better thermal stability and the best degradation of rhodamine B solution relatively. The proper preparation conditions of Zn O catalyst by DBS/hexanol/cyclohexane/zinc nitrate solution are as follows: Zn2+ concentration is 0.75 mol/L, DBS concentration is 0.10 mol/L, hexyl alcohol consumption is 15 m L, crystallization temperature is 300 °C and crystallization time is 2 h. At this point, the decolorization rate of rhodamine B solution can up to 97%, and the prepared Zn O photocatalyst has better catalytic performance,A mixture of zinc nitrate and aluminum nitrate solution as the water phase, Al2O3/Zn O composite photocatalyst was prepared by DBS/hexanol/cyclohexane/water. The size of Al2O3/Zn O particles is small and distribute in range of 10-20 nm, the samples have both Al2O3 and Zn O crystal styles, with high crystal transformation temperature and good thermal stability. With the catalytic degradation of rhodamine B as the probe reaction, the optimum synthetic conditions of Al2O3/Zn O composite photocatalyst is determined as follows: hexanol as co-surfactant, molar ratio(Al/Zn) is 15%, calcination temperature is 500 ℃. Besides, the reaction conditions of Al2O3/Zn O composite photocatalyst is: the dosage of Al2O3/Zn O composite photocatalyst is 0.04 g, intial concentration of dye is 4 mg/L, selecting active rhodamine B solution, and the power of high pressure mercury lamp is 450 W. At this point, the decolorization rate of rhodamine B solution can up to 98%, and indicate that the prepared Al2O3/Zn O composite photocatalyst has better catalytic performance.