Enhanced selective acetone gas sensing performance by fabricating ZnSnO3/SnO2 concave microcube

Unique ZnSnO3/SnO2 concave microcubes with different doping amount of SnO2 (5 wt%, 10 wt%, 15 wt%) were obtained by a simple hydrothermal reaction. A sequence of experiments based on different ratios of Na3C6H5O7·2H2O and SnCl4·5H2O were carried out, exploring the reason for the formation of concave microcube. Many SnO2 nanoparticles were densely anchored on the rough surface of the as-obtained concave microcubes, which further increased the specific surface area and provided more active sites for the adsorption-desorption of gas molecules, delivering outstanding gas sensing performances. A high gas sensing response value (18.3), fast response/recovery time (5/6 s), good reproducibility and selectivity as well as extraordinary stability have been recorded in the case of ZnSnO3/10 wt%SnO2 composites. In comparison with the pure ZnSnO3 and ZnSnO3/SnO2 sensors with other ratios (5 wt%, 15 wt%), the ZnSnO3/10 wt%SnO2 sensor displayed a distinct enhancement in gas sensing properties toward acetone, which can be owed mainly to increased high surface to volume ratios, the presence of oxygen vacancies and the synergistic effect between ZnSnO3 and SnO2.