Hexylresorcinol calix[4]arene-assisted synthesis of ZnO–Au micro–nano materials with enhanced photodegradation performance to degrade harmful organic compounds

In this study, hexylresorcinol calix[4]arene-ZnO-Au (HRCA-ZnO-Au) micro–nano materials are synthesized by a simple atmospheric reflux. AuCl4− ions are in situ reduced to Au by the phenolic hydroxyl groups of amphiphilic HRCA and deposited on the primarily formed ZnO sheets, which prevents Zn2+ ions in the solution from depositing at this position. Finally, the flake sample is obtained. HRCA and chloroauric acid effectively shape the morphology of ZnO from micron-sized flowers to nanometer sheets, and they significantly increase the specific surface area of the sample. Low temperature calcination of the HRCA-ZnO-Au composite micro–nano materials partially removes calixarene molecules and exposes the surface of ZnO–Au. Thus, the photocatalytic activity of ZnO–Au is significantly improved due to the synergistic effect between ZnO and Au.