Effect of multi-walled carbon nanotubes loaded with Ag nanoparticles on the photocatalytic degradation of rhodamine B under visible light irradiation

Multi-walled carbon nanotubes loaded with Ag nanoparticles (Ag/MWNTs) were prepared by two methods (direct photoreduction and thermal decomposition). The photocatalytic activity of Ag/MWNTs for the degradation of rhodamine B (RhB) under visible light irradiation was investigated in detail. The adsorption and photocatalytic activity tests indicated that the MWNTs served as both an adsorbent and a visible light photocatalyst. The photocatalytic activity of MWNTs was remarkably enhanced when the Ag nanoparticles were loaded on the surface of MWNTs. Moreover, the visible light photocatalytic activity of Ag/MWNTs depended on the synthetic route. On the basis of the experimental results, a possible visible light photocatalytic degradation mechanism was discussed.

Research highlights▶ The visible light photocatalytic activity of Ag/MWNTs was explored. ▶ Electrochemical impedance spectroscopy (EIS) was applied to characterize the electron transfer rate of Ag/MWNTs. ▶ Ag/MWNTs was found to be an ideal alternative to Pt/MWNTs for the rhodamine B degradation due to its low cost and high visible light photocatalytic activity.