纵向多孔及实心ZnO微纳米棒的制备、表征及其光催化性能研究

以硝酸锌和六次甲基四胺为原料,水为溶剂,采用低温水热法制备出具有优异光催化性能的六方纤锌矿结构ZnO微纳米棒,并研究了合成过程中磁力搅拌及原料溶液浓度对制备产物形貌及光催化性能的影响,建立了其光催化降解甲基橙的动力学方程。结果表明,搅拌条件下制备的产物为纵向多孔的棒状ZnO,无搅拌条件下制备的产物为实心ZnO纳米棒.优选出的硝酸锌和六次甲基四胺浓度均为0.025mol/L。相比于实心ZnO纳米棒,纵向多孔的棒状ZnO具有更优异的光催化性能,在紫外光照射20min后,对甲基橙的降解率达到100%。通过动力学模型拟合发现,纵向多孔的棒状ZnO具有更大的催化速率常数(0.2942 min~(-1)),是实心ZnO纳米棒催化速率常数(0.1306min~(-1))的2.25倍。

The Axially Porous and Solid ZnO Micro-nanorods:Preparation, Characterization and Photocatalytic Properties

Hexagonal wurtzite structured ZnO micro-nanorods with excellent photocatalytic performance were synthesized by a low temperature hydrothermal method using zinc nitrate and hexamethylene tetramine as raw mate-rials and water as solvent.The influence of the magnetic stirring and hydrothermal solution concentration of the raw materials on the product morphology and the photocatalytic performance were investigated in detail,and the dynamics equation of the photocatalytic degrading methyl orange was established.The results showed that the as-prepared pro-duct was axially porous rod-like ZnO or solid ZnO nanorods when the magnetic stirring was or was not carried out,re-spectively.The optimal concentrations of zinc nitrate and hexamethylene tetramine are both 0.025 mol/L.Compared to solid ZnO nanorods,the axially porous rod-like ZnO has more excellent photocatalytic performance,and the degra-dation rate of MO solutions over it could reach 100% under UV light irradiation for 20 min.The result of the kinetics model fitting showed that the catalytic rate constant (0.2942 min-1 )of the axially porous rod-like ZnO is 2.25 times as much as that of solid ZnO nanorods (0.1306 min-1 ).