Radical macro spatial separation: a novel way to enhance the photocatalytic efficiency

Abstract

Radical macro spatial separation can be achieved via a new photocatalytic system separating electrons and holes into two reaction chambers which are connected by a salt bridge. In this system, ZnO single crystal was selected as a photocatalyst and Rhodamine B was employed as model pollutant. As a polarized single crystal, ZnO can separate photogenerated electrons and holes, as well as the radicals generated by two kinds of photogenerated carriers. Without direct irradiation, only ˙OH is found in the chamber that was in contact with the O polar plane. It shows that our system achieves a radical spatial separation which cannot be achieved in conventional photocatalytic systems, and thereby obtains higher photocatalytic efficiency. Spontaneous polarization electric field induced crystal plane selective photocorrosion in the ZnO single crystal is also found, which will help to design more efficient and more corrosion-resistant ZnO-based photocatalytic materials.