Synthesis and characterization of tin oxide-multiwalled carbon nanotube composite material as carbon monoxide gas sensor

Gas sensor based on nano-structured tin oxide (SnO<inf>2</inf> ) and multi-walled carbon nanotube (MWCNT) composite material has successfully been synthesized. Reflux method was used to produce SnO<inf>2</inf>-MWCNT powder with various ratio 1:0, 4:1, 2:1, 1:1 and 0:1. The XRD result shows that the synthesized material comprises of the combination of carbon elements (MWCNT) and SnO<inf>2</inf> of the crystalite cassiterite phase. BET analysis shows that MWCNT particles increase the specific surface area of SnO<inf>2</inf> particles. SEM images show the morphology of the SnO<inf>2</inf> nanoparticle composite attached to the MWCNT wall with a diameter of 40-60 nm and dispersed around it. Gas sensor testing was carried out at room temperature, 50, 100, 150, 200, 250, 300, and 350^o C. All sensor samples were exposed to 30 ppm CO gas for 15 minutes. . It was found that sample with 1:0 ratio gives the best response with 98.91 at 350^o C. CO gas tests have also been carried out at various concentration 10, 30, 50 and 70 ppm to 4:1 SnO<inf>2</inf>-MWCNT sample at 150^o C. The higher the CO gas concentration, the greater the response. SnO<inf>2</inf>-MWCNT with 4:1 ratio at 50^o C has the fastest response time of 10 s and the fastest recovery time of 3 s. © 2019 Trans Tech Publications, Switzerland.