Abstract
Constructing core-shell heterostructures can effectively improve the hindered issues such as decreased sensitivity and poor selectivity from the chemoresistive gas sensors in the complex atmosphere. Herein, an effective hydrothermal-water bath treatment combined strategy was designed to obtain the unique ethanol adsorption preferred ZnIn_2S_4 sheet shell/In_2O_3 sphere core (ZnIn_2S_4 @In_2O_3) nanosphere (NS) heterostructures. Particularly, according to the characterization and gas sensing test results, the chemoresistive sensor of ZnIn_2S_4 @In_2O_3 NS-2 with the highest chemisorbed oxygen concentration shows satisfactory selectivity to ethanol vapor, and the response is the highest (54) compared to other composite controls, which is almost 4-fold of that of the pure In_2O_3 NS reference. Besides, the relatively lower working temperature (220 °C), low limit of detection (LOD, 30 ppb) and long-term stability were also obtained. The enhanced performance of the core-shell ZnIn_2S_4 @In_2O_3 NS-2 based sensor may be due to the synergistic effect between ZnIn_2S_4 sheets and In_2O_3 sphere moieties. Meanwhile, the large specific surface area from the outer shell of ZnIn_2S_4 sheets is also another contribution factor, which supplies the most chemisorbed oxygen sites and transportation channels to promote the interfacial gas diffusion, catalytic oxidation and product desorption.
NSTL
Elsevier