Facile preparation of CNT/Ag2S nanocomposites with improved visible and NIR light photocatalytic degradation activity and their catalytic mechanism

Abstract

In this work, a series of carbon nanotubes (CNT)/Ag2S hybrid nanocomposites were successfully prepared by a facile precipitation method. Transmission electron microscope (TEM) observation indicates that Ag2S nanoparticles with an average particle size of ~25 nm are uniformly anchored on the surface of CNT. The photocatalytic activities of the CNT/Ag2S nanocomposites were investigated toward the degradation of rhodamine B (RhB) under visible and near-infrared (NIR) light irradiation. It is shown that the nanocomposites exhibit obviously enhanced visible and NIR light photocatalytic activities compared with bare Ag2S nanoparticles. Moreover, the recycling photocatalytic experiment demonstrates that the CNT/Ag2S nanocomposites possess excellent photocatalytic stability. The photoelectrochemical and photoluminescence measurements reveal the efficient separation of photogenerated charges in the CNT/Ag2S nanocomposites. This is the dominant reason behind the improvement of the photocatalytic activity. Based on active species trapping experiments, the possible photocatalytic mechanism of CNT/Ag2S nanocomposites for dye degradation under visible and NIR light irradiation was proposed.