Tourmaline Modified BiFeO3 Based MEMS Sensor with Temperature-Dependent Dual Selectivity for Detecting Acetone and Hydrogen Sulfide

In recent years, design and synthesis of heterostructured nanomaterials with high gas-sensing performance for detection of flammable and toxic gases has attracted much research interest. In this paper, pristine and tourmaline-modified BiFeO3(BFO) nanomaterials were successfully synthesized via a sol-gel method. The BiFeO3 modified with tourmaline could remarkably enhance the gas response and exhibit some novel properties. The tourmaline/BiFeO3 3wt% (tourmaline/BiFeO3 composite with the 3wt% tourmaline) MEMS sensor exhibited temperature-dependent dual selectivity to CO at 150 °C and H2S at 225 °C. The tourmaline/BiFeO3 3wt% based MEMS sensor response toward 0.77 ppm of acetone (C3H6O) is 4.3 at 150 °C and toward 0.75 ppm of hydrogen sulfide (H2S) reaches 11.6 at 225 °C. Furthermore, the sensor possessed good repeatability and antihumidity interference. The dramatically improved sensing performance could be ascribed to the spontaneous polarity of tourmaline, the electron transfer was modulated by the heterojunction in the interface between the BiFeO3 and tourmaline nanostructure. The easy fabrication and good gas sensing performances make our sensors highly attractive for ultrasensitive C3H6O and H2S gas detection with less power consumption. Figure 1