The invention discloses a preparation method of a
lanthanum ferrite /
zinc oxide composite material, which comprises the following steps: preparing
lanthanum ferrite LFO, ultrasonically stirring
ferric nitrate nonahydrate,
lanthanum nitrate hexahydrate and a dispersing agent in a hydrothermal
solvent to obtain a
mixed solution, preparing an LFO / ZnO
composite material, dispersing the LFO prepared in the step S1 and
zinc acetate in
ethanol, performing ultrasonic treatment, heating and stirring, and condensing and refluxing to obtain the LFO / ZnO
composite material. Cooling, and continuously stirring in an ice-water bath; dropwise adding a NaOH
ethanol solution at the temperature of 0 DEG C, and stirring for 2 hours; adding deionized water, stirring, centrifuging to remove the supernatant, dispersing the precipitate
powder in
ethanol, and carrying out
hydrothermal reaction; after the
hydrothermal reaction is finished, centrifuging the solution, and after
centrifugation is finished, pouring out the solution to obtain a precipitate; washing with deionized water and an ethanol solution,
drying the precipitate, and calcining the dried
powder in a
muffle furnace to obtain a p-n type LFO / ZnO composite material; according to the method, the size of lanthanum ferrite can be accurately regulated and controlled through a cooperative regulation strategy of the
solvent proportion and the ligand size, and different types of gases can be accurately distinguished.