S-doped SnO2 nanoparticles with a smaller grain size for highly efficient detection of greenhouse gas hexafluoroethane

Hexafluoroethane (CF3CF3) is a significant greenhouse gas and a potential threat to the environment as emissions increase. However, there is no simple and effective method to detect CF3CF3 yet. Hence, we first attempted to use metal oxide semiconductor (MOS) gas sensors for CF3CF3 detection. Pristine SnO2 and S-doped SnO2 (1–3, representing different S contents) nanoparticles were synthesized. S elements successfully doped into the crystal structure of SnO2. The optimized sensor (S-SnO2-2) shows excellent CF3CF3 sensing performance at 200 °C. The response value of the S-SnO2-2 sensor to 25 ppm CF3CF3 at 200 °C is 13.44, which is significantly higher than the pristine SnO2 response value of 4.45. The S-SnO2-2 sensor also exhibits a short response and recovery time (10 s and 148 s), reliable linear response, excellent selectivity, low limit of detection (0.5 ppm), satisfactory reparability, and good long-term stability. The sensing process of CF3CF3 has been investigated by means of gas chromatography-mass spectrometry (GC-MS). The excellent sensing performance of CF3CF3 in the S-SnO2-2 sensor can be attributed to the abundant active oxygen, excellent electron capture capability, and fast charge transfer of S-SnO2-2, which also benefits from its smaller grain size. This work is the first to report CF3CF3 sensing using MOS gas sensors and has developed a feasible way for CF3CF3 detection.