| 초록 |
Highly ordered TiO2 nanotube arrays were prepared by anodization of Ti foil in aqueous electrolyte solution of 1 M Na2SO4 + 0.5 wt.% NH4F at a constant voltage of 50 V for 12 h using Ni sheet as a cathode, followed by calcined at various temperatures. The effect of calcination temperature on the microstructures, morphologies, and electrochemical properties of the as-prepared nanotube arrays was investigated. The results showed that the as-prepared nanotube arrays before being calcined were amorphous and could transform to anatase phase at a heat treatment temperature higher than 400°C. As the calcination temperatures increased, crystallization of anatase phase enhanced and rutile phase appeared at 600°C. However, further increasing the calcination temperature would cause the collapse of nanotube arrays due to intense phase transformation from anatase to rutile and directly from Ti to rutile. |
