Synthesis of SnO₂ nanoparticles for formaldehyde detection with high sensitivity and good selectivity

During the detection of industrial hazardous gases, like formaldehyde (HCHO), the selectivity is still a challenging issue. Herein, an alternative HCHO chemosensor that based on the tin oxide nanoparticles is proposed, which was obtained through a facile hydrothermal method. Gas sensing performances showed that the optimal working temperature located at only 180 °C, the response value of 79 via 50 ppm HCHO was much higher than that of 35 at 230 °C. However, the compromised test temperature was selected as 230 °C, taking into account the faster response/recovery speeds than 180 °C, named 20/23versus 53/60 s, respectively. The response (35) of the SnO₂ nanoparticles-based sensor to 50 ppm of HCHO is about 400% higher than that of bulk SnO₂ sensor (9), especially when the gas concentration is 1 ppm, SnO₂ nanoparticles also has a higher sensitivity which may possibly result from more exposed active sites and small size effect for nanoparticles than for bulk ones. The gas sensor based on SnO₂ nanoparticles can be utilized as a promising candidate for practical low-temperature detectors of HCHO due to its higher gas response, excellent response-recovery properties, and perfect selectivity.