Design and fabrication of Sm2O3/multi-walled carbon nanotube hybrid sensors for detection of LPG and ethanol gases

Hybridizing hierarchically structured Sm 2 O 3 with multi-walled carbon nanotube (MWCNTs) is highly desirable for improving the performance of Sm 2 O 3 -based gas sensors. In this work, we developed a simple solvothermal method combined with heat treatment for the preparation of flower-like Sm 2 O 3 /MWCNTs nanocomposites with a flexible three-dimensional nanostructure. The characterization results showed that 4–8 μm Sm 2 O 3 flower-like structures, formed by Sm 2 O 3 nanosheets, were attached to the MWCNTs surface. The Sm 2 O 3 -MWCNTs composite possesses a SBET of 212.5 m 2 g −1 and higher V Tot of 0.756 cm 3 g −1 . Gas sensors based on the Sm 2 O 3 /MWCNTs nanocomposites exhibited a greater response, better selectivity, lower operating temperature, and good recovery towards acetone compared with pure Sm 2 O 3 . Additionally, the sensors show a total recovery of their baseline resistance and reasonable response and recovery times. 5.0 wt% MWCNT-doped Sm 2 O 3 sample is the most sensitive sensor towards LPG and ethanol and the related response value are 18.2 and 14.3. Moreover, the Sm 2 O 3 /MWCNT hybrid sensor delivers a response and recovery time of 7 and 10 s, respectively. In addition, the fabricated sensor showed high stability, which is conducted by long period (60 days) sensing response for both gases. The improved mechanism of the fabricated sensor was also discussed in detail.