Preparation Of YFeO₃ Nanofibers By Electrospinning And Its Application In Sensors

In recent years,the perovskite-type metal oxide YFeO3 has received attention.As a stable narrow bandgap P-style semiconductor material,YFeO3 has excellent photocatalytic activity and magnetooptical characteristics,and widely used in the field of the photocatalyst.In this study,one-dimensional YFeO3 nanofibers were prepared by electro spinning.The phase structure,microstructure and thermal stability were characterized by XRD,SEM,and TG-DSC.The influence of the parameters in the electrospinning process on the diameter of nanofibers was investigated.YFeO3 nanofibers were applied to gas sensors,and the effects of temperature,gas type and concentration on their gas sensitivity were studied.The results show that air humidity?solution viscosity and the voltage are the main influence factors of the nano-fiber diameter in the process of electrospinning and the diameter grows up with the air humidity?solution viscosity and the voltage.And the influence of advance speed and distance on diameter is not obvious.The nano-fiber diameter decreases with the increase of calcining temperature,and the surface becomes smoother.In the calcining temperature rage 700-800?,the result is a stable orthorhombic phase and less hexagonal phase.When the temperature is 800-850?,the hexagonal phase gradually disappears and transforms into an orthogonal phase.When the calcination temperature is higher than 850?,the hexagonal phase disappears and completely transforms into an orthogonal phase.YFeO3 has a higher response to reducing gases CO and H2,but less responsive to O2 and SO2.The peak response of YFeO3 calcined at 800? to CO and H2 was 420 and 480?,respectively,and the peak of YFeO3 calcined at 850? was 400 and 460? respectively,for two gases.The response of YFeO3 to different concentrations of the two gases showed a linear relationship.The increase in test temperature has no significant effect on response time,but after exceeding the response peak temperature,the recovery time decreases with the temperature rise.When the reducing gas is adsorbed on the surface of YFeO3,electrons are released into the semiconductor to form cations,electrons enter the valence band and combined with holes,the hole concentration is decreased,the electrical conductivity is decreased,and the electric resistance is increased;when the oxidizing gas is adsorbed on the surface of YFeO3.The valence band electron moves to the conduction band and combines with gas to form anions.the number of holes in the valence band increases,the electrical conductivity increases,and the electrical resistance decreases.As the gas concentration decreases,the above process proceeds in reverse and the conductivity returns to its original size.