Hierarchical ZnO nanostructures: controlling the synthesis and photocatalytic decomposition of nitrogen monoxide

Abstract

Hierarchical metal oxide nanostructures that possess unique chemical and physical properties have attracted widespread interest recently because of their potential applications in catalysis, biological engineering, and photoelectronic devices. Herein, hierarchical ZnO nanostructures (ZONS) with unique structural features such as dumbbells, twin-prisms, whiskers, and nanorod bundles have been fabricated using a facile hydrothermal method with lysine as an in situ source of OH⁻ and structure-directing agent. The effect of the lysine amount on structural features was systematically investigated, in order to elucidate the roles of lysine in the growth process. It was found that lysine plays an important role in controlling the shape and assembly of the hierarchical structures of ZONS using its capping and chelating abilities. The photocatalytic activities of different ZONS were evaluated using the photocatalytic decomposition of nitrogen monoxide. The decomposition properties were found to be strongly dependent on the surface area and the assembled features of the structure.