Selective carbon monoxide sensing properties of bismuth iron oxide

Among nitrogen oxide (NO2), methane (CH4), isobutane (i-C4H10) and carbon monoxide (CO) gases; selective CO sensing has been reported for perovskite p-type bismuth iron oxide (BFO) gas sensor at 200 degrees C. We have adopted glycine based auto-combustion route to synthesize phase pure BFO powders. For 100 ppm of CO, response% is reported to be 60% with response and recovery times of 85 s and 102 s respectively. BFO sensor yields high sensitivity (n similar to 1.27) and high selectivity with respect to NO2 (selectivity coefficient, kappa similar to 217.5), CH4 (kappa similar to 994.2) and i-C4H10 (kappa similar to 8.4). The sensor also exhibits excellent repeatability and long-term stability. The selective CO sensing characteristics of BFO sensor has been attributed to the catalytic nature of BFO surface towards efficient CO oxidation. Lower metal-oxygen binding energy, favorable 'd' orbital electron configuration of surface iron cations and nature of the surface adsorbed species are demonstrated to be the three dominant parameters in yielding superior catalytic activity towards CO oxidation in order to promote selective CO sensing.