Synthesis and characterization of Al-doped ZnO/CdO heterostructured nanocomposites for enhancing NO2 gas sensing performance

In this study, both petal-shaped Al-doped (1 at%) ZnO (Al-ZnO) and Al-ZnO/CdO heterostructured nanomaterials were successfully designed and synthesized via a facile two-step hydrothermal method. Characterizations of crystallinity, morphology and composition were performed by XRD, HR-TEM, FE-SEM, EDS, XPS, and Raman. The results of XRD, HR-TEM, and XPS reveal that Al-ZnO/CdO materials grew well together and coexisted. The petal shaped Al-ZnO/CdO heterostructured nanocomposite with 2 mol% of CdO was exposed to NO2, NH3, CH3COCH3, C2H5OH, and H2 at an optimal operating temperature of 200 °C. Compared with pure ZnO and Al-ZnO, the petal-shaped Al-ZnO/CdO heterostructured nanocomposite exhibited specifically high enhanced performances in response and selectivity for the NO2 gas sensing. Moreover, the sensitivity to NO2 displayed excellent linear dependence in the range of 0.5 ∼ 5 ppm, which shows promise in the detection of NO2 using a petal-shaped Al-ZnO/CdO heterostructured nanocomposite-based sensor.