ZnO nanoplate clusters with numerous enlarged catalytic interface exposures via a hydrothermal method for improved and recyclable photocatalytic activity

Abstract

To promote the photodegradation rate of hazardous pollutants in aqueous solution, enlarging the effective catalytic interface of the photocatalysts is one of the efficient ways for environmental purification. However, the photocatalysts could not exhibit superior photocatalytic performances unless the exposing extent to the environment of the enlarged catalytic interfaces was taken into account. Here, a facile hydrothermal synthesis of a large-scale and highly efficient photocatalyst composed of ZnO nanoplate clusters with steric exposing catalytic interfaces of (001) planes is demonstrated. The aluminum ions are used as the capping agent to suppress the familiar preferred c-axis orientation and facilitate the polar surface growth of ZnO. The steric exposing structure is related to the suppressed effect of the aluminum ions on the double nucleation and growth process which occur both on substrate and in solution. Large-scale nanoplates aggregated in clusters are successfully prepared on a zinc substrate, permitting easy recycle of the photocatalysts. Surprisingly, ZnO nanoplate clusters exhibit a fourfold enhanced photodegradation rate than that recorded for the pure ZnO nanorod arrays under UV irradiation. The demonstrated higher photodegradation rates and recyclability indicate that ZnO nanoplate clusters are candidates for efficient photocatalysts, replacing the traditional nanoparticle photocatalysts.