Synthesis and comparison of the photocatalytic activities of flame spray pyrolysis and sol–gel derived magnesium oxide nano-scale particles S. Demirci a,b,n , B. Öztürk a,b , S. Yildirim a,b , F. Bakal a,b , M. Erol c , O. Sancakoğlu b , R. Yigit d,e , E. Celik b,d,e , T. Batar f a Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Buca 35160, Izmir, Turkey b Dokuz Eylul University, Department of Metallurgical and Materials Engineering, Buca 35160, Izmir, Turkey c Katip Çelebi University, Department of Metallurgical and Materials Engineering, Çiğli 35620, Izmir, Turkey d Dokuz Eylul University, Center for Fabrication and Appl. of Electronic Materials (EMUM), Buca 35160, Izmir, Turkey e Dokuz Eylul University, Department of Nanoscience and Nanoengineering, Buca 35160, İzmir, Turkey f Gediz University, Department of Mechanical Engineering, Seyrek 35665, Izmir, Turkey article info Keywords: Magnesium oxide Flame spray pyrolysis Sol–gel process Photocatalysis Methylene blue abstract In this study, nano-scale magnesium oxide particles were synthesized by means of flame spray pyrolysis and sol–gel techniques. Phase structures, morphologies, particle size, specific surface area and optical band gap were determined using an X-ray diffractometer (XRD), scanning electron microscope (SEM), particle size analyzer, Brunauer–Emmett– Teller (BET) specific surface area analyzer and UV diffused reflectance spectroscopy (UV DRS), respectively. In order to determine photocatalytic activity of the nano-scale particles, aqueous methylene blue (MB) solutions were employed. The photocatalytical degradation rates of MB solutions were determined through absorbance measurements performed via UV–vis spectrophotometer. Fourier transform infrared spectroscopy (FTIR) studies confirmed the formation –OH hydroxyl and other groups provide by MB solutions, after photocatalytic studies. It was found that both flame spray pyrolysis and sol–gel synthesized MgO nano-scale particles exhibited appreciable photocatalytic activity for the degradation of MB dye under UV light irradiation with small differences. Moreover, the effects of particle size and surface area on the photocatalytic properties were investigated in detail. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction Magnesium oxide (MgO) is a versatile oxide material with respect to its wide range of utilization, such as in catalysis, hazardous waste treatment, antimicrobial materi- als and refractory materials [1]. Recently, MgO has attracted tremendous attention on account of these immense app- lications. Particularly, in the field of catalysis, MgO has become a promising material in the roles of both catalyst and catalyst support in many organic reactions [2]. Over the past several years, numerous semiconductor metal oxides such as TiO 2 , ZnO, WO 3 , Fe 2 O 3 and CuO were used as photocatalyst materials for the degradation of organic pollutants in water or air [3]. Among these oxides, MgO has received considerable attention about its photo- degradation efficiency, thanks to its electronic structure and chemical properties [3,4]. Photocatalysis is a surface Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/mssp Materials Science in Semiconductor Processing http://dx.doi.org/10.1016/j.mssp.2015.02.029 1369-8001/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author at: Dokuz Eylul University, Department of Metallurgical and Materials Engineering, Buca 35160, Izmir, Turkey. Tel.: þ90 232 301 90 01. E-mail address: selim.demirci08@hotmail.com (S. Demirci). Materials Science in Semiconductor Processing 34 (2015) 154–161