Photocatalytic Reduction of Cr ^VI by TiO ₂ /GO Nanocomposite

Abstract

Abstract Graphene Oxide (GO) was successfully deposited on TiO 2 NPs through sol‐gel process. The fabricated TiO 2 /GO (T/G) nanocomposite was used for reduction of Cr VI under simulated solar light illumination. 10 wt. % GO was used for the preparation of T/ G nanocomposite. Several analytical methods such as powder X‐ray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and UV‐visible diffuse reflectance spectra (DRS) spectrophotometer was used to characterize the samples. The PXRD revealed the formation of the anatase phase of TiO 2 NPs and T/G nanocomposites, as per literature more favourable form of TiO 2 for photocatalytic activity. The average crystallite size was found 5.1 nm and 23 nm for TiO 2 NPs and T/G nanocomposite respectively. Under the simulated sunlight illumination, the TiO 2 NPs was excited to generate the electron‐hole pairs and then the photo‐generated electron transferred by the GO to the Cr VI which further converted into Cr III . The band gap for T/G nanocomposite was calculated 2.92 eV. Under visible light,27.3 % photoreduction of (10 mg/L) Cr VI solution at λ max= 347 nm was achieved within 90 min on the T/G sample at the pH 5–6 while overall reduction was 48 % including adsorption. The rate of reaction was found 0.00305 min −1 and the order of reaction was pseudo first order.