Platinum-supported tungsten trioxide composite photocatalyst as well as preparation method and application

The invention discloses a platinum-supported tungsten trioxide composite photocatalyst as well as a preparation method and an application. The catalyst consists of sodium tungstate and lead acetate ina ratio being 1:1. The preparation method comprises the following steps: (1) dissolving 1.6 mmol of sodium tungstate dihydrate and lead acetate trihydrate in ultrapure water, adding 1 ml of a surfactant to lead acetate trihydrate, slowly dropwise adding lead acetate trihydrate to a sodium tungstate dihydrate solution, and performing stirring to obtain a uniform mixed solution; (2) pouring the mixed solution in a hydrothermal kettle, placing the hydrothermal kettle in a blast drying oven for heat treatment, after the reaction ends, naturally cooling the hydrothermal kettle to room temperature,and performing repeated washing to obtain a primary product; (3) adding 20 ml of a saltpeter solution to the primary product, and carrying out stirring, hydrothermal treatment, washing and drying toobtain an intermediate prod