Facile synthesis of in situ CNT/WO3 center dot H2O nanoplate composites for adsorption and photocatalytic applications under visible light irradiation

Composites of refluxed carbon nanotubes (CNTs) at different contents and orthorhombic tungsten oxide hydrate (WO3 center dot H2O) were prepared via acid precipitation at room temperature. The CNTs produced a new phase of monoclinic tungsten oxide dihydrate WO3 center dot 2H(2)O, caused the breakage of WO3 center dot H2O nanoplates, and affected the microstrain in the nanocomposites. The CNTs also enhanced the absorbance in the visible range and increased the specific surface area and pore volume but abnormally enlarged the optical bandgap, which was assigned to the emerging monoclinic WO3 center dot 2H(2)O phase. The adsorptivity and photocatalytic activity of the nanocomposites increased remarkably with CNT content. H2O2 strongly enhanced the photocatalytic activity of the pristine and nanocomposite samples, implying the vital role of photogenerated electrons in the photocatalytic process. Among the synthesized samples, the sample with 20 wt.% CNTs showed the highest adsorptivity and photocatalytic efficiency under visible light irradiation. It also exhibited good reusability in methylene blue degradation and applicability in degrading different organic dyes. This study presents a simple method to prepare CNT@WO3 center dot H2O nanocomposites with a large surface area, a high adsorptivity, and a high photocatalytic activity under visible light irradiation.