Enhancement of the NH3 gas sensitivity by using the WO3/MWCNT composite-based sensors*

Multi-walled carbon nanotubes (MWCNTs) were prepared by thermal chemical vapor deposition at 750 °C, and WO3nanobricks with an average size of 80 nm were synthesized by a hydrothermal route. MWCNTs and WO3 were mixed at different mass ratios in dimethylformamide solution to obtain composite materials. The WO3/MWCNT composite-based sensors were used for detection of NH3 gas. The gas-sensitive properties of the sensors were compared with those of pure CNT- and WO3-based sensors. The fabricated WO3/CNT composite sensors exhibited higher response, and faster response/recovery time than the other sensors at room temperature. In this work a possible mechanism conducting to the improvement of the hybrid sensors performance is proposed