A three-dimensional hierarchical CdO nanostructure: Preparation and its improved gas-diffusing performance in gas sensor

In order to develop a gas sensor with improved gas-diffusing performance, a three-dimensional (3D) hierarchical CdO nanostructure with a novel bio-inspired morphology was reported. The CdO nanostructures which exhibit a profile of natural leaveleaf were synthesized via a solvothermal approach combining with an annealing process. The solvothermally synthesized CdS precursors were converted into CdO under an optimal annealing condition. In gas-sensing measurements, acetone and diethyl ether were employed as target gases. The results show that the as-fabricated gas sensor exhibits fast response and recovery speeds toward analytes. The mechanism for the improved performance was demonstrated from the gas diffusion through the 3D hierarchical nanostructure. The kinetic processes of gas adsorption and desorption show that the 3D leaveleaf-shaped structure is significant to achieve an enhanced diffusing property. Additionally, a principal component analysis method was used to investigate the recognizable ability of the presented sensor. It is found that acetone and diethyl ether can be distinguished clearly. These findings indicate that the bio-inspired CdO nanostructure can be a promising candidate for the development of fast-responding gas sensors. Moreover, such bio-inspired structure would be also valuable for the design of some other novel nanomaterials.