The Gas Sensor Based on Novel Hierarchical Ni_(0.7)Zn_(0.3)o Hollow Porous Microspheres for VOCs Detection

摘要

Bimetallic oxides have attracted substantial interest for gas sensing since their high compositional flexibility allows for tunable properties. In this work, we design and constructed a rocksalt solid solution Ni_(0.7)Zn_(0.3)O with hierarchical and hollow porous microspheres by deriving from bimetallic Zn/Ni-based metal-organic frameworks for the first time. This hollow spheres are constructed with a thin shell (100 nm) that assembled with smaller nanoparticles (15～30 nm). This unique morphology would provide a high special surface area that is very advantageous for gas sensing. The gas sensing performance of this rocksalt solid solution were investigated for the first time. The gas sensor based on these Ni_(0.7)Zn_(0.3)O microspheres exhibits a highly sensitivity toward to low concentration about 500 parts per billion (ppb) of acetone (S=1.21), aniline (S=1.44) and TEA (S=1.34) at 350°C, the response/recovery speed is extremely fast (less than 15 s) and selectivity is good (its responses to 5 ppm of other VOCs, such as ethanol, benzene, xylene, formaldehyde, ammonia, methylbenzene, formamide and ethanamide are less than 1.05). Even at low temperature (～200°C), the sensor still shows a good gas sensing performance. Moreover, a special response mode has been found in this work. This hierarchical nanostructured rocksalt Ni_(0.7)Zn_(0.3)O solid solution proposes a novel gas sensing material for achieving highly selective and sensitive gas sensing performance.