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

Vu Truong Duong, Cong Tu Nguyen, Huu Bac Luong, Lan Anh Luu, Duc Chien Nguyen and Huu Lam Nguyen

Abstract

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