Sonochemically prepared nanosized BiFeO3 as novel SO2 sensor

Bismuth ferrite (BiFeO3) without any co-formed impurity phase was synthesized by sonochemical method. The average crystallite sizes of synthesized BiFeO3 for two sonication times of 40 min and 2 h were found to be 38 and 32 nm and the corresponding band gaps were 2.1 and 2.2 eV, respectively. In contrast to BiFeO3 synthesized by conventional precipitation route which gives rise to co-formed impurity phases, the sonochemically prepared phase-pure BiFeO3 nanoparticles exhibited an excellent low-ppm SO2 sensing behaviour with fast response and recovery. Also the sonochemically synthesized BiFeO3 was selective to SO2 in presence of carbon monoxide and butane and may turn out to be a potential functional material for SO2 leak alarms.