The invention discloses a preparation method of a
metal oxide SnO2 and
halide perovskite quantum dot Cs3Bi2I9
heterojunction visible-light-driven photocatalyst, which comprises the following steps of (1) preparing a
tin tetrachloride pentahydrate solution and a
sodium hydroxide solution, dropwise adding the
sodium hydroxide solution into the
tin tetrachloride pentahydrate solution, stirring, dropwise adding absolute ethyl
alcohol, stirring, heating, reacting, then washing,
drying and
grinding, (2) adding
cesium iodide and
bismuth iodide into N, N-
dimethylformamide, and performing ultrasonic treatment to obtain a precursor solution, then adding the solution into
toluene for reaction, and then centrifuging,
drying and
grinding, and (3) adding the two kinds of
powder into isopropanol liquid for ultrasonic treatment, then stirring and centrifuging,
drying and
grinding to obtain the
heterojunction visible-light-driven photocatalyst. The method for preparing the
heterojunction photocatalyst is easy to operate, mild in reaction condition, low in
equipment requirement and free of a complex synthesis device, and the catalyst is applied to
nitrogen oxide degradation and can remarkably improve the
nitrogen oxide removal efficiency.