ZnFe2O4/ZnO nanosheets assembled microspheres for high performance trimethylamine gas sensing

ZnFe 2 O 4 /ZnO nanosheets assembled microspheres (ZnFe 2 O 4 /ZnO SAS) were successfully constructed by hydrothermal synthesis of ZnO nanosheets assembled microsphere and subsequent growth of ZnFe 2 O 4 nanoparticles on it via a facile solution method. The morphologies and components of as-synthesized ZnFe 2 O 4 /ZnO SAS composites were varied with growth time, and ZnFe 2 O 4 /ZnO SAS composite with the growth time of 30 min (ZnFe 2 O 4 /ZnO SAS30) consisted of porous nanosheets assembled by small ZnFe 2 O 4 and ZnO nanoparticles. The composites were applied as sensing film for trimethylamine (TMA) sensing. ZnFe 2 O 4 /ZnO SAS30 based sensor exhibited good selectivity and higher response to TMA than that of sensors based on bare ZnO microspheres precursor, ZnO/ZnFe 2 O 4 nanoparticle composite and other ZnFe 2 O 4 /ZnO SAS composites, respectively. At 240 °C, the ZnFe 2 O 4 /ZnO SAS30 based sensor exhibited 31.5–100 ppm TMA with a quick response and recovery time of 3.1 s and 5.7 s, respectively, and even as low as 0.1 ppm TMA can be detected. Meanwhile, the corresponding cycling performance and stability was also checked. Such favorable comprehensive sensing performance of ZnFe 2 O 4 /ZnO SAS30 to TMA was attributed to its unique hierarchical structure and ZnO/ZnFe 2 O 4 heterojunctions . All results enabled potential applications of ZnFe 2 O 4 /ZnO SAS30 composite in TMA sensing.