MOF-derived hierarchical ZnO/ZnFe2O4 hollow cubes for enhanced acetone gas-sensing performance

ZnO/ZnFe2O4 hollow cube composites with heterogeneous structure are synthesized by a facile strategy through simple and direct pyrolysis of FeIII-modified Zn-based metal–organic frameworks. The as-synthesized ZnO/ZnFe2O4 hollow cubes have well-defined cube morphology with an ∼2 μm and multiple porous shell constructed from interpenetrated ZnO and ZnFe2O4 heterogeneous nanoparticles, providing structurally combined mesoporous channels for facilitating the diffusion and surface reaction of gas molecules. In addition, a comparative sensing performance investigation between ZnO/ZnFe2O4 hollow cubes and singular ZnO demonstrates that, in contrast with ZnO, the ZnO/ZnFe2O4 hollow cubes show significantly enhanced chemical sensing sensitivity towards low-concentration acetone. Furthermore, the ZnO/ZnFe2O4 hollow cubes exhibit good reproducibility and selectivity towards gaseous acetone. The enhanced sensing performance of the MOF-derived ZnO/ZnFe2O4 hollow cubes is ascribed to the unique hierarchical structure with high specific surface area, abundant exposed active sites with surface-adsorbed oxygen species and heterojunctions formed at the interfaces between ZnO and ZnFe2O4.