Nanometer iron oxide photocatalyst and preparation method thereof

The invention discloses a nanometer iron oxide photocatalyst and a preparation method thereof. The preparation method comprises the following steps: A, putting 20 to 30 parts of ferric chloride and 1 to 2 parts of titanium dioxide into a hydrochloric acid solution, performing heating and stirring to prepare a precursor; B, putting the precursor into a reaction kettle, heating to 200-210 DEG C, and keeping the temperature for 2-3 hours; C, adding pure water with the temperature of 80-90 DEG C into a product in the reaction kettle, and performing stirring and crystallizing; D, performing suction filtration and washing on a product in the step C; E, putting the product in the step D into a muffle furnace, heating to 850-950 DEG C, and performing calcining; and F, reducing the temperature of the muffle furnace at the speed of 150 DEG C / h, when the temperature of the muffle furnace is reduced to 350 DEG C, carrying out heat preservation on the muffle furnace for 1 h, then, rising the temperature of the muffle furnace to 500 DEG C, performing heat preservation for 3 h, and then, taking out a product in the muffle furnace and putting the product into pure water to be cooled to the room temperature. The defects in the prior art can be overcome, and the reduction speed of the activity of the iron oxide photocatalyst is reduced.