By reducing the aqueous mixture of electrostatically modified multi-walled carbon nanotubes (f-MWCNT) and palladium (Pd) using NaBH4, a nanocomposite was synthesized. The syllable structure of the f-MWCNT and f-MWCNT/ Pd nanocomposite was investigated by analytical tools FESEM and TEM respectively. f-MWCNTs matrix reinforced with Pd nanoparticles are utilized for sensing
CH4 with its dilution varying from 0.5-100 ppm in air at room temperature (RT=27°C). The f-MWNT/Pd nanocomposite-based sensor for CH4 gas show several merits over conventional catalytic beads and MOS based sensors in context of reduced size, reduced power consumption and ease of fabrication. At room temperature, the nanocomposite's temporal electrical responses to CH4 were measured. It exhibited a response magnitude of ∼20-45.71% with a small variation of ±2% towards 0.5-100 ppm CH4. Furthermore, the responses were extremely reversible and repeatable, implying that it may be used to detect CH4 at ambient temperature. It has also been demonstrated experimentally that an excellent response time (≈ 20 s) and the recovery time (≈ 25 s) for these devices were recorded for CH4. The influence of external temperature and humidity on the CH4 sensor was also investigated in order to assess its long-term stability and self-life. The results showed that very small change is observed over a wide of temperature from 25-70oC and that for %Rh from 20-90%. Therefore, the reported CH4 sensor absolutely demonstrated long-term stability at ambient conditions and hence, these devices can prove to be ideal for CH4 leakage detection for practical real time applications. A sensing mechanism by which CH4 is detected by f-MWCNT/Pd nanocomposite is also elaborately discussed.