Metal–Organic Framework-Derived Hierarchical Nanostructured Ni_0.7Zn_0.3O Hollow Porous Microspheres for Selective and Sensitive aniline Sensing

Bimetallic oxides are becoming a widely attended gas-sensing material in recent years for their good thermal and chemical stability, especially as their highly flexible composition allows for tunable properties. In this work, a hierarchical nanostructured rocksalt solid solution Ni 0.7 Zn 0.3 O with hollow porous microspheres has been first prepared by deriving the microspheres from Zn/Ni-based metal–organic frameworks. These nanostructured Ni 0.7 Zn 0.3 O spheres were constructed with a nanosized shell (about 100 nm), which consisted of 15–30 nm nanoparticles. This nanostructured morphology provided a high special surface area that is an advantage for enhancing gas-sensing properties. The gas sensor based on these nanostructured Ni 0.7 Zn 0.3 O hollow spheres has presented a high sensitivity and selectivity toward aniline at a low concentration of about 500 ppb ( S = 63%) at 300 °C, and the response/recovery speed is very fast (less than 15 s). This hierarchical nanostructured rocksalt Ni x Zn (1– x ) O solid solution proposes an excellent selective and sensitive gas-sensing material for detecting aniline. Moreover, this method for preparing rocksalt Ni x Zn (1– x ) O solid solution can be widely used to design and synthesize bimetallic oxides with hollow and hierarchical nanostructures.