In situ growth of Ag/AgCl on the surface of CNT and the effect of CNT on the photoactivity of the composite

Abstract

CNT/Ag/AgCl was fabricated by a facile solvothermal method. The introduced carbon nanotube (CNT) was both in the interior and surface of the Ag/AgCl. The composites were characterized by X-ray diffraction (XRD), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), UV-vis absorption spectra, photoluminescence (PL), electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic abilities of Ag/AgCl and CNT/Ag/AgCl were valued by degradation of methyl orange (MO) dye, with results showing that the photocatalytic ability of CNT/Ag/AgCl (with trace carbon nanotube content) is much higher than that of pure Ag/AgCl. The photoactivity of the composite depends mainly on the amount of carbon nanotube. The SEM-EDS results suggest that the carbon nanotube and the Ag/AgCl combined well, with the carbon nanotube dispersing well over the whole of the Ag/AgCl particles (both the interior and surface). The formation process for CNT/Ag/AgCl is also proposed. The EIS result indicates that CNT/Ag/AgCl has much lower resistance than Ag/AgCl. The carbon nanotube is beneficial for electron transfer in the CNT/Ag/AgCl system. In particular, in the interior of the composite the carbon nanotube can transfer electrons generated in the Ag/AgCl to the surface, which could solve the problem of high electron–hole recombination in the Ag/AgCl system, therefore, the photoactivity of Ag/AgCl could be enhanced. A possible reaction mechanism is also proposed.