Enhancement of Photocatalytic Degradation of Methyl Orange by Supported Zinc Oxide Nanorods/Zinc Stannate (ZnO/ZTO) on Porous Substrates

Dye wastewater from textile industries is reported to be a major river pollutant. Zinc stannate (ZTO) was grown directly on zinc oxide (ZnO) nanorod-coated polyester fiber membranes and porous ceramic substrates by a mild hydrothermal method, where the nanorods supplied zinc ions for ZTO growth. Photocatalytic degradation of a methyl orange aqueous solution under UV-light irradiation was monitored for up to 3 h duration. The higher photocatalytic activity of ZnO/ZTO catalysts on ceramic substrates was attributed to the large surface area of the nanocomposites. 50% methyl orange and ∼95% methyl orange could be degraded within 1 and 3 h of UV-light irradiation, respectively, by using the porous-ceramic-supported catalysts (C-ZnO/10ZTO), because of efficient charge separation. Moreover, the formation of ZTO islands on ZnO nanorods led to an enhancement in the photocatalytic activity in the exposed areas of electron-rich ZnO nanorods.