Fabrication of 3D Multi-Edges Cube Porous SnO2/ZnO Composites as High-Performance NOx Gas Sensor

In this study, a kind of novel porous 3D multi-edges cube SnO₂/ZnO composite with n-n heterojunctions was prepared through a facile hydrothermal route. A kind of ordered mesoporous ZnO must be used as precursor in the hydrothermal reaction which was fabricated by soft-template method. The surfaces of the 3D multi-edges cube SnO₂/ZnO composite were distributed with ordered mesoporous of 10.2 nm. The grain refinement effect was happen by SnO₂, it led to the specific surface area of the material reached to 135.641 $\text{m}^{\textsf {2}}\cdot \text{g}^{\textsf {-1}}$ , which was nearly 3.9 times of ZnO matrix. At room temperature (25°), the 3D multi-edges cube SnO₂/ZnO nanomaterial showed excellent gas response to NO_x, whose response to 100 ppm NO_x reached 60.41±0.5%, the response time was only 2 s, and the detection limit was 0.2 ppm. It broke the tradition that SnO₂/ZnO composite showed gas response to NO_x only in relatively high temperatures.