Co1−xBaxFe2O4 (x = 0, 0.25, 0.5, 0.75 and 1) nanoferrites as gas sensor towards NO2 and NH3 gases

• Published in: RSC advances 2020-09, Vol.10 (58), p.35265-35272
• Main Authors: Pawar, Hariom, Khan, Meenu, Mitharwal, Chhavi, Dwivedi, U K, Mitra, Supratim, Rathore, Deepshikha
• Format: Article
• Language: English
• Subjects: Ammonia; Chemical precipitation; Chemical synthesis; Chemistry; Dielectric properties; Dissipation factor; Electric polarization; Gas sensors; Gases; Nitrogen dioxide; Optical properties; Spectrum analysis
• ISSN: 2046-2069
• DOI: 10.1039/d0ra04303f

Co1−xBaxFe2O4 (x = 0, 0.25, 0.5, 0.75 and 1) nanoferrites were synthesized using a controlled chemical co-precipitation technique. Their structural, optical, dielectric and gas sensing properties were characterized by X-ray diffractometry, UV-Vis spectroscopy and an LCR meter with a gas sensing unit. The crystalline sizes were estimated using the Scherrer formula and were found to be 7.8 nm, 14.4 nm, 21.8 nm, 16.5 nm and 30.3 nm for x = 0, 0.25, 0.5, 0.75 and 1, respectively. The fundamental optical band gaps were calculated by extrapolating the linear part of (αhυ)2vs. hυ of the synthesized nanoferrites. The SEM and EDX spectra also confirmed the formation of nanoferrites. Dramatic behavior was observed in the dielectric constant and dissipation factor with varying temperature, which provides a substantial amount of information about electric polarization. The synthesized nanoferrites were tested towards NO2 and NH3 gases. The order of sensitivity (%) towards NH3 was analyzed as x = 0.75 > x = 0.5 > x = 0.25 > x = 0 > x = 1, while the order was x = 0 > 0.75 > 1 > 0.5 > 0.25 for NO2 gas.