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 (WO3-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 WO3-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 WO3 and P25, which could be ascribed to the coating of WO3 by amorphous carbon and the construction of defects (oxygen vacancy) in WO3. 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.