Synthesis, characterization and gas sensing properties of ZnO-decorated MWCNTs

In this work, ZnO-decorated multi-walled carbon nanotube (MWCNT) nanocomposites prepared using an in-situ method involving the thermal evaporation of Zn powders in the presence of MWCNTs. The gas sensing characteristics of the MWCNT/ZnO nanocomposites are studied, and results for the material characterizations for the synthesized nanocomposites confirm the formation of well-distributed ZnO nanoparticles onto MWCNTs, creating MWCNT/ZnO nanocomposites. The gas sensing properties of the MWCNT/ZnO nanocomposite gas sensor, such as response, cross-sensitivity, and response-recovery time, are investigated and compared with a bare MWCNT sensor. The decoration of ZnO nanoparticles greatly improves the gas sensing properties of bare MWCNTs. We discussed the possible mechanisms for the enhancement of sensing capabilities. The results suggest that decoration of n-type semiconducting oxide materials, such as ZnO in the form of nanoparticles, is a promising strategy for improvement of gas sensing properties of p-MWCNTs.