Preparation and gas-sensitive properties of hollow Zn2SnO4/SnO2 nano-cubes

Metal oxide semiconductors with porous or hollow heterostructures can significantly improve the gas sensing performance of materials by promoting the increase of free electron density and the diffusion of test gas. Firstly, ZnSn(OH)6 was synthesized by one-step hydrothermal method, then hollow Zn2SnO4/SnO2 nano-cubes with the n-n heterojunction between Zn2SnO4 and SnO2 grains was obtained by calcination in air. The Zn2SnO4/SnO2 sensor possesses good response (Ra/Rg) toward ethanol and formaldehyde compare to other volatile organic compound (VOC) gas. In detail, the Ra/Rg is 11.12 and 9.16 in 100 ppm 200 °C ethanol and formaldehyde, respectively. Moreover, the repeatability, stability and ambient humidity as well as enhancement mechanism of this sensor are systematically discussed. These results indicate that Zn2SnO4/SnO2 nano-cubes with hollow structure is a promising sensing material for VOC gas detection.