Triple-shelled ZnO/ZnFe2O4 heterojunctional hollow microspheres derived from Prussian Blue analogue as high-performance acetone sensors

Abstract

Semiconductor oxides with hierarchically hollow architecture can provide significant advantages as sensing materials for gas sensing by facilitating the diffusion of target gases and the surface reaction. A cost-efficient and facile strategy is developed to scalably fabricate triple-shelled hollow binary ZnO/ZnFe2O4 (ZZFO) metal oxides microspheres with excellent intimate heterojunctions through a morphology-inherited annealing treatment of single-resource Prussian Blue analogue of Zn3[Fe(CN)6]2·xH2O solid microspheres as self-sacrificial templates. The porous hybrid ZZFO triple-shelled hollow microspheres (TSHMSs) are demonstrated to be composed of crystalline ZnO and ZnFe2O4 nano-domains with well homogeneous dispersion at the nanoscale and large void spaces between adjacent shells. When evaluated as sensors towards acetone vapor, benefiting from the striking synergy and interplay between active bicomponents and the intrinsic structural advantages, the as-fabricated ZZFO TSHMSs sensor exhibited high performances, including excellent sensitivity, good selectivity and high reversibility, rapid response ability at ultralow working temperature (140°C). Of great significance, these prominent findings may pave the way towards optimizational design and efficient fabrication of mixed metal oxides derived from other PBAs or even other MOFs as high-performance gas sensors in the future.