Highly efficient SnO2-Carbon nanosphere heterojunctions decorated with Ag for detecting isopropanol at low operating temperatures

The design of a sensing material for detecting isopropanol gas with low operating temperature is extremely important for miniaturization and wearability of gas sensors. Herein, a novel gas sensor based on SnO 2 -Carbon nanosphere heterojunctions decorated with Ag nanoparticles (SCA) was fabricated and its gas sensing performance was evaluated and compared systematically. The measurement results indicated that the sensing performance was influenced by the ratio of Sn/C and the length of Ag plating, and the SCA sensor provided the best response. For 100 ppm isopropanol at 100 °C, the SCA sensor exhibited a response value of 50.51, a response time of 7 s and a recovery time of 60 s. The enhanced sensing performance and reduced operating temperature of the SCA could be attributed to the synergistic effect of the SnO 2 -Carbon nanosphere heterojunctions and the significant catalytic performance of the decorated Ag nanoparticles. In addition, the density functional theory calculation method based on the first-principles theory was used to study the adsorption performance and electronic behavior, as well as   the influence of Ag decoration on SnO 2 for isopropanol detection. The calculated results were consistent with the experimental results.