TiO2@NbSe2 decorated nanocomposites for efficient visible-light photocatalysis

Abstract

In this article, 2D NbSe2 nanosheets are combined with TiO2 nanoparticles to prepare visible-light active composite photocatalysts using sol gel reflux synthesis. The concentration of NbSe2 is varied as 0.5, 1, 2 and 3 weight percent with respect to TiO2. The prepared samples are characterized via scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), UV–Vis spectroscopy and Brunauer–Emmett–Teller (BET) surface area measurement techniques to determine morphology, dimensional aspects of nanosheets, phase, optical properties and surface area of the nanocomposites, respectively. From SEM images TiO2 nanoparticles are observed on the surface of NbSe2 sheets in all the samples. AFM gives an estimate of thickness of NbSe2 nanosheets ranging from 25 to 40 nm corresponding to 30–50 layers. XRD confirms the presence of both components in nanocomposites. UV–Vis spectrum of NbSe2 nanosheets reveals its visible-light absorption capability and a narrow band gap. The surface area values as obtained from BET technique vary from 120 m2/g for TiO2 NPs alone to 162 m2/g for 2 wt% NbSe2 in TiO2 nanocomposites. To study the visible-light photocatalytic behavior the composites are employed for the photodegradation of rhodamine B (RhB) dye under visible-light irradiation. The prepared nanocomposites substantiate to be highly effective photocatalysts for degradation of organic dye due to visible-light absorption offered by NbSe2 together with increased surface area. The sample having 2 wt% NbSe2 shows best performance with almost complete (i.e., 98%) RhB degradation in just 60 min of visible-light irradiation. NbSe2 can facilitate the increased induction of electrons into the CB of TiO2 by visible-light absorption and higher surface area in composites also adds to substantially improved photocatalytic activity exhibited by the nanocomposites.