The preparation of Janus Cu(OH)2@Cu2O/Cu mesh and application in purification of oily wastewater

Abstract A Janus Cu(OH)2@Cu2O/Cu mesh has been synthesized by UV irradiation and in situ hydrazine vapor reduction of superhydrophobic Cu(OH)2/Cu mesh prepared by electrochemical anodization of Cu mesh followed by ODS modification. The Cu2O nanoparticles derived from partial reduction of Cu(OH)2 deposit on the Cu(OH)2 to form a core-shell heterostructure, which endows the as-prepared mesh with micro/nanoscale hierarchical morphology. The wettability of different sides of the mesh can be easily controlled by tuning irradiation time and subsequent reduction. As a result, a unidirectional water penetration phenomenon can be obtained. In addition, based on the asymmetric wettability as well as the photocatalytic activity of the Cu(OH)2@Cu2O nanoneedle decorated mesh, the ultrahigh permeation flux and high separation efficiency with excellent in situ photocatalytic ability can also be achieved. This work may provide a rational and convenient strategy to construct Janus mesh with visible light photocatalysis toward in situ dual-functional water purification.