Enhanced photocatalytic activity of Bi12O17Cl2 nano-sheets via surface modification of carbon nanotubes as electron carriers.

A novel carbon nanotubes modified Bi12O17Cl2 composite (CNTs/Bi12O17Cl2) was prepared via hydrothermal method. The chemical structures, morphologies, optical properties of the synthesized samples were revealed by XRD, XPS, SEM, TEM, BET and UV-vis DRS measurements. The photocatalytic activity of the CNTs/Bi12O17Cl2 composite was evaluated with degradation reaction of rhodamine B (RhB) under visible light. CNTs/Bi12O17Cl2 exhibited improved photocatalytic activity in comparison with pure Bi12O17Cl2, and kept favorable stability and recyclability in the reaction. The relatively high photocatalytic activity of CNTs/Bi12O17Cl2 resulted from the enhanced separation efficiency of photo-induced charges, which were revealed by the photoluminescence spectra and transient photocurrent measurements. CNTs loaded at the surface of Bi12O17Cl2 sheets acted as electron carriers to efficiently transfer the photoinduced electrons, namely to promote the separation of photoinduced electrons and holes, thus improving the photocatalytic activity of the composite materials. At last, a possible photocatalytic reaction mechanism over the CNTs/Bi12O17Cl2 composite was proposed based on the results of trapping experiment, ESR measurements and the band energy analysis.