Abstract
The preparation of catalysts supported by anodic alumina layers have been developed and practically applied in Japan. In order to reduce the cost of these catalyst supports, we tried to use rapid anodic alumina layers, but by the former method, the value of BET surface area of these layers was too small to use as a good catalyst support. As a solution of this problem, the purpose of this work is to develop the new method for increasing the BET surface area of rapid anodic alumina layers to improve activities of these alumina layers which used as catalyst supports. For preparing these layers, aluminum plates were rapidly anodized in sulfuric acid solution to obtain porous alumina layers with about 100µm of thickness. Then, these plates were soaked in sulfuric acid solution in order to widen the pore size of these alumina layers. After that, they were soaked in hot deionized water for hydration treatment. The experimental results showed that after pore widening treatment and hydration treatment, the value of BET surface area of rapid anodic alumina layers increased from 60 (by former method) to 200 m2.g -1-Al2O3 and, it was clarified that the alumina layer with bigger pore size has a bigger BET surface area after hydration treatment. The new method can be applied for not only rapid anodic alumina layers but also for other anodic alumina layers such as those formed in oxalic acid, chromic acid and so on.
