Nano-Structures & Nano-Objects 18 (2019) 100292 Contents lists available at ScienceDirect Nano-Structures & Nano-Objects journal homepage: www.elsevier.com/locate/nanoso Synthesis of biphasic nanomaterials based on ZnO and SnO 2 : Application towards photocatalytic degradation of acid red dye Pradeep Dammala a , Joel Machado b , Barkha Rani a , Sudha Murali a , Suman Devi c , Meitram Niraj Luwang b,∗ , Niroj Kumar Sahu a,∗ a Centre for Nanotechnology Research, Vellore Institute of Technology, Vellore 632014, TamilNadu, India b Chemical Engineering and Process Development Division, National Chemical Laboratory, Pune 411008, India c Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, RafiMarg, New Delhi 110001, India highlights • Specific formulation of Zn 2 SnO 4 /SnO 2 and ZnO/SnO 2 heterostructures were made in solvothermal method. • pH and sequence of precursor’s ad- dition during reaction significantly impact on the final heterostructures. • Different heterostructures show dif- ferent extent of photocatalytic ac- tivity. • ZTO/SnO 2 possess superior activity towards the degradation of AR-183 dye under UV-irradiation. graphical abstract article info Article history: Received 29 October 2018 Received in revised form 5 March 2019 Accepted 22 March 2019 Keywords: Biphasic Nanocomposites ZnO/SnO 2 Zn 2 SnO 4 /SnO 2 AR-183 Photocatalysis abstract Zn 2 SnO 4 /SnO 2 and ZnO/SnO 2 biphasic nanocatalysts have been synthesized by a facile solvothermal method using ethylene glycol (EG) as solvent in three different ways maintaining the pH of the solution at either 3 or 9 followed by calcination at 700 ◦ C. The nanocatalysts are characterized by different techniques to investigate their structure, composition, morphology and optical properties. The XRD results indicate the formation of pristine biphasic composites. The UV-absorbance and photoluminescence spectra confirms the formation of biphasic composites as well as presence of large number of defects in the prepared nanocatalysts. The biphasic nanocomposites possess better photocatalytic activity towards the degradation of Acid Red-183 (AR-183) dye than pristine SnO 2 and ZnO nanoparticles. This is mainly due to better charge separation, minimal recombination rate of charge carriers and defect-riched structures of nanocatalysts. © 2019 Published by Elsevier B.V. 1. Introduction Wastewater treatment from industries became important due to rapid increase of industries. Many techniques have been intro- duced for the treatment but ended up in generation of secondary ∗ Corresponding authors. E-mail addresses: mn.luwang@ncl.res.in (M.N. Luwang), nirojs@vit.ac.in (N.K. Sahu). pollutants as a result. In this aspect, advanced oxidation process (AOP) became an important influential process to fossilize these organic pollutants by creating reactive species (OH . radicals). Semiconductor metal oxide (SMO) photocatalysts is an outmost AOP’s technique in complete fossilization of harmful organic pol- lutants to harmless smaller compounds (CO 2 and H 2 O) [1,2]. Among the toxic organic pollutants, AR-183 dye is very harmful and causes eye, skin and digestive tract irritation. Further, its inhalation may cause respiratory tract infection [3,4]. Numerous https://doi.org/10.1016/j.nanoso.2019.100292 2352-507X/© 2019 Published by Elsevier B.V.