Preparation method of lanthanum doped bismuth phosphate photocatalyst

The invention discloses a preparation method of a lanthanum doped bismuth phosphate photocatalyst. The method comprises the steps that bismuth phosphate pentahydrate is dissolved in an aqueous nitric acid solution, and a solution A is obtained; lanthanum nitrate hexahydrate is dissolved in water, and a solution B is obtained; a phosphorus source compound is added to the solution B, and a solution C is obtained; the solution A is added dropwise to the solution C and stirred continuously, and a solution E is obtained; the solution E is transferred to a reaction kettle for a hydrothermal reaction, and a product is cooled to the room temperature after the reaction is finished; a product is subjected to filtering and separation, a precipitation product is washed with distilled water and ethyl alcohol and dried, and the lanthanum doped bismuth phosphate photocatalyst is obtained. The lanthanum doped bismuth phosphate photocatalyst is prepared by one step on the basis of the low-temperature hydrothermal reaction. Th