This invention belongs to the field of functional materials and gas sensing, specifically disclosing a method for preparing a
bismuth ferrite gas sensor and its application. The method employs gradient annealing, placing the
bismuth ferrite sample in a series of atmospheres with continuously increasing
oxygen partial pressures,
ranging from zero
oxygen partial pressure to 100%
oxygen partial pressure. The
oxygen vacancy concentration, ferroelectric domain order, and gas-sensing performance of the sample after annealing are measured, establishing a correlation between oxygen
partial pressure,
oxygen vacancy concentration, ferroelectric domain order, and gas-sensing performance, thereby improving the gas-sensing properties of the material. This invention also provides the application of this method in the preparation of
bismuth ferrite gas sensors. The above method can maximize the sensor's sensitivity.