Synthesis Of Low-dimensional Materials From AAO And Their Applications In Environmental Catalysis

Catalysis is one of the fields which have initiated the use of low dimension materials for a long time. The paper herein reports the synthesis of a variety of ultra-fine materials grounded on anodic aluminum oxide (AAO) by hydrothermal method, sol-gel method and chemically modification method. Potential applications in environmental catalysis of these ultra-fine materials prepared in the work have also been studied in the paper:(1) Nano-particles, nano-rods and sub-micron tubes of TiO₂ were synthesized with the template of AAO by sol-gel method. The diameters of the tubes are in the ranges of 100-150 nm when pH values 1.6-2.4. It is confirmed that there are mesopores around 10 nm in the walls of the tubes.(2) Without any other support during etching in dilute phosphoric acid aqueous solutions (6 wt %), alumina nano-tubes, nano-belts and nano-wires were fabricated from AAO under different etching times. Besides the etching effect of phosphoric acid on the structure, a loosening effect also occurs along the boundaries of the colloid bundles. Because of the incorporation of acid anions during anodization, the composition of the individual cell wall is affected and three different layers formed. Therefore, the etching rates of different layers of the cell wall are influenced, which leads to the formation of various nano-structures.(3) The surface acidity (resulted from anion incorporated during anodization) of alumina got from AAO and its ordered orientation are believed to be the reasons to explain its catalytic effects in pyridine...