Self-assembly of carbon nanotube/graphitic-like flake/BiOBr nanocomposite with 1D/2D/3D heterojunctions for enhanced photocatalytic activity

A self-assembled nanocomposite of lamellar BiOBr covalently bonded with conductive network of dispersive one-dimensional carbon nanotubes (1D CNT) and two-dimensional reduced graphitic-like flakes (2D GF) had been in situ constructed using one-pot facile solvothermal technique. Through self-assembly, BiOBr/CNT/GF (BiOBr/CG) displayed three-dimensional architectures in which a strong interfacial contact interaction and covalent banding between BiOBr nanostructures and CNT/GF network appeared. Furthermore, visible-light-driven catalytic activity of BiOBr/CG for RhB dye degradation was superior to that of pure BiOBr or BiOBr/C. Interestingly, the photodegradation activity of the BiOBr/CG nanocomposite could be improved further by subsequent facile annealing treatment, in which the annealed BiOBr/CG-DS had degraded almost 97.9% of RhB dye within only 100 min of visible-light irradiation. Moreover, analysis of the photodegradation mechanism revealed that the repression of electron-hole recombination in the nanocomposites, with sufficient covalent interfacial contact with CNT/GF as effective electron collecting and transferring system, were responsible for the outstanding photocatalytic performance. This effect, in turn, led to the continuous generation of [rad]O²− and [rad]OH reactive oxygen species for the degradation of RhB dye, which was verified by active species trapping and ESR spectra.