Core-shell Au@ZnO nanoparticles derived from Au@MOF and their sub-ppm level acetone gas-sensing performance

Noble metal@metal oxides have attracted extensive attention as gas-sensing materials due to the formation of Schottky junction, modulating surface physicochemical properties of oxide nanomaterials. Herein, a facile way was developed to construct core-shell Au@ZnO nanoparticles through direct pyrolysis of Au@Zn-based metal-organic framework (MOF). The obtained Au@ZnO nanoparticles have -50 nm Au nanoparticles as cores and interpenetrated ZnO nanoparticles (-20 nm) as porous shells. When applied as gas-sensing materials, the unique core-shell Au@ZnO nanoparticles exhibited significantly enhanced gas-sensing response and selectivity towards sub-ppm level acetone at 300 degrees C. The response value of Au@ZnO nanoparticles was 11 times higher than that of singular ZnO nanopartides towards 1 ppm of acetone. The enhanced gas-sensing properties are ascribed to the electronic and chemical sensitization of Au nanoparticles, due to the formation of Schottky junction within AuZnO hetero-interface of core-shell nanoparticles. (C) 2016 Elsevier B.V. All rights reserved.