La

0.8

Ba

0.2

FeO

3

(LBFO)nanopowders are prepared by the sol-gel method.Then the powders are sintered in air and vacuum at temperature of 200℃

respectively

and combined with an oxygen-enriched pressure-holding treatment to fabricate three kinds of LBFO gas-sensing devices.The crystalline phase

micromorphology and composition of the devices are characterized by X-ray diffraction(XRD)

scanning electron microscopy

(SEM) and X-ray photoelectron spectrosscopy(XPS)

and the gas-sensing characteristics of these three gas-sensing devices to carbon dioxide(CO

2

) gas are tested.The results show that the response of the LBFO device after the oxygen-enriched pressure-holding to 500×10

-6

CO

2

gas reaches 1.35 at the optimal operating temperature of 70℃

and the response-recovery time is shortened to 13s.This is because vacuum annealing greatly increases the number of oxygen vacancies on the surface of the material

which significantly increases the proportion of adsorbed oxygen on the surface of material in an oxygen-enriched environment

thereby optimizing the gas-sensing performance of LBFO.This study provides a reference for the fabrication and application of low-cost

simple-process

and high-performance resistive gas sensors.