Enhanced low temperature NO2 detection by SnO2 nanonets: Oxygen vacancy and open hierarchical structures synergize effect

In the light of the increasingly serious air pollution problem, there is an urgent need for effective detection of the toxic and harmful NO2 gas. However, the development of advanced low power consumption, ultra-sensitive, and high stability NO2 sensors is one of the important challenges that urgently needs to be addressed in the field of gas sensing. Here, we propose to utilize the self-assembled view of biological systems for the synthesis of open hierarchical porous and rich oxygen vacancy SnO2 nanonets. The SnO2 nanonets sensor has high selectivity for NO2 gas at 50 degrees C with response up to 18 for 2 ppm NO2. The excellent low temperature NO2 sensing properties are mainly attributed to its specific structure and rich oxygen vacancy. The open surface structure facilitates the flow of gases, while the internal hierarchical porous structure facilitates the diffusion of gases within the material. Meanwhile, a large number of oxygen vacancies provide abundant reactive sites for reactions. This work provides new ideas for the structural design of advanced gas sensing materials.