The photocatalytic degradation of congo red dye (CR) using nanocomposites materials of multi-walled carbon nanotubes combined with some transition metal oxide under visible light irradiation was studied.Multi-walled carbon nanotubes were prepared via chemical vapour synthesis (CVS) and loaded with some transition elements as Cu, Zn, and Cu0.1Zn0.9Onanoparticles, where the ratio of metal was kept c...