Effect of multi-walled carbon nanotubes properties on the photocatalytic activity of bismuth-based composites synthesised via an imidazolium ionic liquid

The use of various types of multi-walled carbon nanotubes in the synthesis of bismuth oxybromide semiconductors via imidazolium ionic liquid was studied in detail. The effect of the MWCNT shape, specific surface area, and various diameters on the morphology, surface properties and photoactivity of the Bi-based composites has been investigated for the first time. So far, the literature has only shown the enhancement of photocatalytic activity of composites containing MWCNT; however, our research shows a broader view of the issue. The photocatalytic activity of the individual composites under UV–Vis irradiation was assessed by the degradation of various micropollutants, showing the diversity of properties of the obtained composites. It is also significant that in the composite system, the imidazolium ionic liquid played a crucial role in the formation of microspheres and acted as a dispersing agent, leading to an even distribution of MWCNTs on the surface of the spherical bismuth oxybromide.