ZnO纳米晶的光催化还原性能研究

Photocatalysed Reduction Nature of Nano ZnO

用直接沉淀法合成粒径小于20 nm的氧化锌颗粒,采用XRD和TEM等技术对其进行表征。在其悬浮体系中对CO32-进行光催化还原实验,以光谱分析法测定还原产物甲酸、甲醛和甲醇的含量,研究催化剂的浓度、CO32-浓度、pH值等因素对还原产物产率的影响。结果表明,纳米氧化锌具有较强的光催化还原活性,光激发生成的电子可将 CO2转化为甲酸、甲醛及甲醇等基本有机原料。

Zinc oxide with its particle size of 20 - 30 nm was prepared by direct precipitate method and characterized with XRD and TEM technologies. The heterogenous photocatalysed reduction of aqueous Na2CO3 was carried out by using nano ZnO semiconductor powders. The formic acid, formaldehyde and methyl alcohol were identified as photoproducts, and were measured spectrophotometrically. The effect of parameters such as sodium carbonate concentration, amount of photocatalyst and different light sources on the yield of photoproducts was also investigated. It shows that nano ZnO has photocatalytic activity. The irradiation leads to the production of electrons in the conduction band of the ZnO semiconductor. It is likely that the photoproduced electrons reduce CO3^2- initially to form HCOO^-, and then to transform into HCHO and CH3OH.