Design of Ag-decorated ZnO concave nanocubes using ZIF-8 with dual functional catalytic ability for decoloring dyes

Abstract

By using ZIF-8 as a precursor, ZnO and Ag/ZnO concave nanocubes (CNCs) were obtained by calcination of ZIF-8 and Ag(NH₃)₂NO₃/ZIF-8 in air, respectively. The Ag/ZnO CNCs were characterized well and due to the suppression of the electron–hole recombination by Ag nanoparticles as well as the electron transfer from ZnO to Ag nanoparticles, the Ag/ZnO CNCs displayed efficient catalytic abilities in the photodegradation of rhodamine B and methyl orange, which were more active than commercial TiO₂ under UV light. On the other hand, the Ag/ZnO CNCs also demonstrated an efficient ability for the hydrogenation of methyl orange in the presence of sodium borohydride by the formation of surface hydrogen species between Ag nanoparticles and borohydride ions; however, under the same conditions, ZnO had no catalytic effect. The results suggest that the Ag/ZnO CNCs could be employed as dual functional catalysts in environmental remediation. Finally, the present work provided an example for the synthesis of metal–metal oxide catalysts in a relatively facile way with multiple functions.