Photocatalytic Degradation of Carbaryl over Novel MWNT-TiO2 Nanocomposite under Visible Light Irradiation

The MWNT-TiO2 nanocomposite was synthesized via direct growth of TiO2 nanoparticles on the surface of the functionalized MWNTs by the hydrothermal treatment and utilized as the photocatalyst in the carbaryl degradation under both visible light and UV light irradiation. Visible-light-driven activity and enhanced UV-light-driven activity are both achieved as the composite MWNTs with TiO2 can efficiently enhance the light absorption and charge separation and then photocatalytic activity. The photodegradation efficiency of carbaryl was examined by HPLC and IC techniques, which demonstrates that carbaryl can be readily degraded under visible light irradiation. Based on the obtained experimental results, assisted with the computer simulation of carbaryl molecule on PM3 level, it is presumed that the degradation of carbaryl starts with the break of N21-C23 and C19-N21 bonds and ends in the generation of naphthalen-1-ol before the ring-opening reaction.