TiO_2胶粒在铝合金表面的电泳沉积及所制薄膜的光催化性能研究

Electrophoretic Deposition of TiO_2 Colloid Particles on Aluminum Alloy Surface and the Photocatalytic Property of the Resulted TiO_2 Membrane

TiO2 membranes were prepared on aluminum-alloy thin plates by electrophoretic deposition and dip coating in a colloid solution of TiO2, respectively. The photocatalytic activity of TiO2 membrane was compared using ethylene as reactant, and the crystal and morphological structure of the membrane were characterized by XRD and SEM. The results showed that a more compact membrane with high loading of TiO2 but lower photocatalytic activity of unit TiO2 mass was obtained by electrophoresis compared with dip coating method. The addition of polyethylene glycol (PEG) to the sol of TiO2 could improve the specific photocatalytic activity (ethylene conversion per unit mass TiO2 and unit area of membrane piece) of the electrophoresis-membrane prepared from the sol, but could not change the specific photocatalytic activity of the dip-coating membrane from the sol. The ethylene conversion on the electrophoresis membrane prepared from the sol containing PEG (50 g·L-1) was 9 times of that on the dip coating membrane. The effect of PEG on the properties of electrophoresis-membrane of TiO2 was attributed to the change of electrokinetic properties of sol. Addition of PEG decreased of colloid particles and the electroosmosis velocity of diffuse layer of colloid particles. These favored the formation of a low compact and porous membrane on the electrode in electric field, and thus increasing the availability of TiO2 in photocatalytic process.

TiO2 membranes were prepared on aluminum-alloy thin plates by electrophoretic deposition and dip coating in a colloid solution of TiO2 respectively. The photocatalytic activity of TiO2 membrane was compared using ethylene as reactant, and the crystal and morphological structure of the membrane were characterized by XRD and SEM. The results showed that a more compact membrane with high loading of TiO2 but lower photocatalytic activity of unit TiO2 mass was obtained by electrophoresis compared with dip coating method. The addition of polyethylene glycol (PEG) to the sol of TiO2 could improve the specific photocatalytic activity (ethylene conversion per unit mass TiO2 and unit area of membrane piece) of the electrophoresis-membrane prepared from the sol, but could not change the specific photocatalytic activity of the dip-coating membrane from the sol. The ethylene conversion on the electrophoresis membrane prepared from the sol containing PEG (50 g(.)L(-1)) was 9 times of that on the dip coating membrane. The effect of PEG on the properties of electrophoresis-membrane of TiO2 was attributed to the change of electrokinetic properties of sol. Addition of PEG decreased potential value of the sol and the mobility of the sol particle, increased viscidity of the colloid, thus decreasing both the electrophoresis deposition velocity of colloid particles and the electroosmosis velocity of diffuse layer of colloid particles. These favored the formation of a low compact and porous membrane on the electrode in electric field, and thus increasing the availability of TiO2 in photocatalytic process.