Unequivocal evidence of enhanced room temperature sensing properties of clad modified Nd doped mullite Bi2Fe4O9 in fiber optic gas sensor

Multiferroic systems are widely evaluated in gas sensing applications recently due to its multifunctional properties and cost effectiveness. In this study, pristine Bi2Fe4O9 (BFO) and 3% of Neodymium (Nd) doped mullite Bi2Fe4O9 (BNFO3) was synthesized using conventional solid state route. Further, energy dispersive spectroscopy (EDS) and X-ray photo electron spectroscopic (XPS) analysis, confirms the incorporation of Nd in BFO without any undesired chemical contamination. In addition, X-ray diffraction (XRD) studies revealed polycrystalline orthorhombic mullite structure of BFO with traces of mixed phases. Also, lattice distortion in BNFO3 was observed as a consequence of Nd doping, which is further confirmed by Raman spectra phonon modes. The gas sensing potential of BFO and BNFO3 samples were studied using clad modified fiber optic gas sensing setup with 4 different volatile gases (ammonia, ethanol, acetone and methanol) at varying concentrations (0–500 ppm). BNFO3 sensor showed highest sensitivity to ammonia gas with percentage sensitivity of about 20% for 500 ppm at room temperature. In addition, the sensor exhibited rapid response and recovery time of about 40 s and 48 s respectively compared to BFO. In brief, BNFO3 clad modified fiber optic sensor can potentially be utilized in sensing ammonia for industrial applications.