Facile preparation of amorphous carbon-coated tungsten trioxide containing oxygen vacancies as photocatalysts for dye degradation

In this work, a simple strategy to fabricate amorphous carbon-coated tungsten oxide with oxygen vacancies (WO 3− x /C, 0 <  x  < 1) via pyrolysis of hybrid-polyoxometalates (hybrid-POMs) in nitrogen atmosphere is reported. TGA, XRD, Raman, FTIR, SEM, TEM, EDS, XPS and BET have been used to characterize the as-prepared products. The results showed that their compositions, microstructures and concentrations of oxygen vacancies were closely related with the species of organic amines in the hybrid-POMs. When the WO 3− x /C composites were used as catalysts for degradation of dyes such as methylene blue, methyl orange and Rhodamine B under visible light irradiation, they showed much enhanced photocatalytic abilities compared to that of WO 3 and P25, which could be ascribed to the coating of WO 3 by amorphous carbon and the construction of defects (oxygen vacancy) in WO 3 . The synthetic strategy presented in our work is simple and shows a great potential in fabricating efficient transition metal-based composites for photocatalysis applications and so on.