Catalyst composition for degrading methylene blue dye in wastewater, preparation method and application thereof

The invention discloses a catalyst composition for degrading a methylene blue dye in wastewater, a preparation method and application thereof. The catalyst composition comprises a ternary composite oxide with a general formula of M2O.Cr2O3. xWO3, wherein M is a sodium element or a potassium element, and x is equal to 1-8; the catalyst composition is prepared by the following steps: sequentially adding an M-element compound, a chromium salt, tungstate and citrate to water, stirring and dissolving the substances, adding ethylene glycol to the solution, stirring for 5-15 minutes, heating the solution to 100-130 DEG C, continuing stirring to form gel, calcining the gel at 500-1100 DEG C for 5-15 hours, and obtaining the finished product. The catalyst composition disclosed by the invention can effectively treat the methylene blue dye wastewater without an oxidizing agent or light exposure at the normal temperature and the normal pressure, and is high in catalytic degradation, simple in technological process, and free of secondary pollution.