Self-assembly tourmaline@BiFeO3 composites with enhanced polarization for dual-selective C3H6O and H2S detection

Ferroelectric oxides with great polarization have attracted much attention due to the polarization modulated carrier behaviors causing high gas sensitivity in detecting hazardous toxic gases. In this work, tourmaline@BiFeO 3 (T@BFO) composites were fabricated by the sol-gel method based on the electrostatic self-assembly strategy for the C 3 H 6 O and H 2 S detection. It is found that BFO nanoparticles are uniformly distributed on tourmaline due to the strong electrostatic field of tourmaline. In comparison with pure BFO, the T@BFO composites showed an improved gas sensitivity. More importantly, the sensor based on 3.0-T@BFO can effectively detect C 3 H 6 O at 150 °C and H 2 S at 210 °C in limits of detection as low as 50 and 7 ppb, respectively. The results exhibit that 3.0-T@BFO composites have lower activation energies (E act ) of C 3 H 6 O at 150 °C and H 2 S at 210 °C, which endow 3.0-T@BFO with dual-selectivity for C 3 H 6 O and H 2 S. The Ex-situ XPS and density functional theory calculations further reveal that tourmaline activates the sensing site of BFO to achieve selective adsorption of C 3 H 6 O at Bi, Fe, and oxygen vacancies sites and H 2 S at surface lattice oxygens, Fe and oxygen vacancies sites. These results provide an efficient strategy to design practice multifunctional and highly sensitive gas sensors for detecting hazardous toxic gases.