Hierarchical kiwifruit-like ZnO/ZnFe2O4 heterostructure for high-sensitive triethylamine gaseous sensor

Hierarchical kiwifruit-like ZnO/ZnFe2O4 heterostructures were prepared using Fe-doped Zn-based metal organic framework as a precursor combined with a subsequent thermolysis strategy. The hierarchical ZnO/ZnFe2O4 composites featured well-organized nanosheet-like surface morphology assembled from interpenetrated ZnO and ZnFe2O4 nanoparticles, facilitating the diffusion and surface reaction of specific gas molecules in gas sensing applications. As expected, a comparative study of triethylamine gas sensing performance between the kiwifruit-like ZnO/ZnFe2O4 heterostructures and single-component ZnO proved that the former composites showed improved triethylamine gas sensitivity with Ra/Rg = 40.5 at an operating temperature of 200 °C. Specifically, the ZnO/ZnFe2O4 heterostructure exhibited a fast response/recovery time of 32 s/41 s and excellent long-term stability of up to one month towards gaseous triethylamine. The enhanced trimethylamine gas sensing mechanism is ascribed to the intriguing kiwifruit-like hierarchical architecture of ZnO/ZnFe2O4 heterojunction with ultrathin nanosheets on its surface and abundant accessible reactive sites interacting with the target gas molecules. This work offers new opportunities for rationally designing gas sensing materials by assembling the multi-component architectures.