Nano-Ag particles doped TiO2 for efficient photodegradation of Direct azo dyes

Silver nanoparticles doped TiO2 has been prepared and characterised by surface analytical methods such as BET surface area, scanning electron micrographs (SEM), X-ray diffraction (XRD), energy dispersive X-ray micro analysis (EDX), electron spin resonance (ESR) and diffuse reflectance spectroscopy (DRS). We have investigated the photocatalytic degradation of two Direct diazo dyes, Direct red 23 (DR 23) and Direct blue 53 (DB 53) in the aqueous suspensions of TiO2 and Ag deposited TiO2 nanoparticles under UV-A light irradiation in order to evaluate the various effects of silver deposition on the photocatalytic activity of TiO2. The presence of silver in TiO2 was found to enhance the photodegradation of DR 23 and DB 53. The higher activity of silver doped TiO2 is due to the enhancement of electron–hole separation by the electron trapping of silver particles.

Graphical abstractPhotocatalytic degradation of two Direct diazo dyes, Direct red 23 (DR 23) and Direct blue 53 (DB 53) in the aqueous suspensions of TiO2 and Ag deposited TiO2 nanoparticles with UV-A light have been investigated. The enhancement of photocatalytic activity of Ag doped TiO2 is found to be due to the following mechanism. Ag nanoparticles be deposited on TiO2 act as electron traps, enhancing the electron–hole separation and the subsequent transfer of the trapped electron to the adsorbed O2 acting as an electron acceptor. Figure optionsDownload full-size imageDownload as PowerPoint slide