Ag modified bismuth ferrite nanospheres as a chlorine gas sensor

Pure phase bismuth ferrite (BiFeO₃, BFO) nanospheres were synthesized via a sol-gel method, and Ag was loaded on the surface of BFO by photodeposition. The effects of the Ag-modification on the morphologies and microstructural characteristics were investigated using transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) analyses. Only BFO peaks but no Ag peaks were observed for all samples in the XRD patterns, which is related to the small size and low loading of Ag. The gas-sensing tests show that the response of 4 mg AgNO₃ modified BiFeO₃ (ABFO4) was 72.62 to 10 ppm Cl₂ at 240 °C, which was 2.5 times higher than that of the pristine BFO. Such outstanding gas sensing performances are attributed to the fact that the presence of Ag not only increases the density of holes and the amount of gas adsorption sites but also has a catalytic effect.