Bharathiar University

About: Bharathiar University is a education organization based out in Coimbatore, Tamil Nadu, India. It is known for research contribution in the topics: Thin film & Adsorption. The organization has 5812 authors who have published 8628 publications receiving 143934 citations. The organization is also known as: BU.

High visible light-driven photocatalytic activity of large surface area Cu doped SnO 2 nanorods synthesized by novel one-step microwave irradiation method

Abstract: The paper investigates the structural, optical and photocatalytic activity of large surface area single crystalline copper (Cu) doped SnO2 nanorods (NRs) synthesized by a novel one-step microwave irradiation method. Powder X-ray diffraction (XRD) analysis confirms that both pure and Cu doped SnO2 are tetragonal rutile type structure (space group P42/mnm) formed during the microwave process within 10 min without any post annealing treatment. Transmission electron microscopy (TEM) reveals that the as synthesized Cu doped SnO2 samples exhibited rod-like shape and the length was less than 80 nm and diameter was about few nanometers. Typical selected-area electron diffraction (SAED) pattern indicates that, the growth direction of Cu–SnO2 nanorod is along [110] direction. The variety of phonon interaction in the pure and Cu doped SnO2 is observed by Raman spectroscopy. Electron paramagnetic resonance and X-ray photoelectron spectroscopy (XPS) confirms that the presence of copper and tin as Cu2+ and Sn4+ in state, respectively. The photocatalytic activity was monitored via the degradation of methylene blue (MB) and Rhodamine B (RhB) dyes and the Cu–SnO2 showed better photocatalytic activity than that of pure SnO2. This could be attributed to the effective electron–hole separation by surface modification.

Mn2+ ion influenced optical and photocatalytic behaviour of Mn–ZnS quantum dots prepared by a microwave assisted technique

Abstract: Fluorescent zinc blende structured pure and Mn2+ ion doped ZnS (Mn–ZnS) quantum dots were prepared via a rapid microwave assisted technique without any surfactants and their photocatalytic activity was tested for the photodegradation of methyl orange dye under UV light irradiation. They were characterized by X-ray diffraction, FE-SEM, UV-Vis and photoluminescence spectroscopies, XRF and BET surface area analysis. The Mn–ZnS quantum dots possessed a cubic blende crystal structure without any impurity phases. The absorption maximum by UV-Vis spectroscopy showed a blue shift with increasing Mn2+ content. Photoluminescence of Mn–ZnS was obtained as a result of combined broad blue emission from sulfur vacancies existing in the ZnS host and orange emission from the 4T1–6A1 transition of Mn2+. The relative intensity of blue to orange emissions was found to be quenched with increasing Mn2+ ion concentration. Methyl orange dye was photodegraded by Mn–ZnS quantum dots effectively up to a doping level of 4.28% Mn2+ and further increase in Mn2+ decreased the photocatalytic activity. Detailed mechanisms of photoluminescence and photocatalytic activity were proposed and discussed. The results suggested that the Mn–ZnS material is a potential candidate for photocatalytic applications.