Photocatalysis with the Use of ZnO Nanostructures as a Method for the Purification of Aquatic Environments from Dyes

The papers devoted to the purification of aquatic environments from industrial contaminants with the use of ZnO based nanosized photocatalysts in the period of 2018–2020 are analyzed. The data published in these papers have made it possible to determine the dye (V) destruction rate used further as a photocatalytic activity criterion. As shown by the comparative analysis of the photocatalytic activity of the studies structures, the highest rates of water purification from industrial azodye contaminants are demonstrated by hybrid ZnO/Au structures. At a destruction rate of V = 10%/min, the ZnO/Au structures are much better than all the other considered types of catalysts due to their morphology, low recombination rate of photogenerated electron-hole pairs, and nanoparticles with an absorption spectrum close to the solar spectrum. The review of literature data shows that the greatest attention of researchers in the considered time period is focused on the problem of the purification of water sources from industrial contaminants and, first of all, azodyes. Essential attention is also paid to the technological approaches applied by the authors to increase the photocatalytic activity of ZnO based nanostructures.