Inorganic Chemistry Communications 145 (2022) 110031 Available online 1 October 2022 1387-7003/© 2022 Elsevier B.V. All rights reserved. Short communication Effect of cobalt incorporation on the photocatalytic degradation of brilliant green using SnO 2 nanoparticles under visible light irradiation K. Sathishkumar a, 1 , S. Ragupathy b, * , Margandan Karunanithi c , M. Krishnakumar d , Durai Mani e, 1 , Young-Ho Ahn e, * a Department of Physics, Annai College of Arts and Science (Affliated to Bharathidasan University, Trichy), Kovilacheri, Kumbakonam 612503, Tamil Nadu, India b Department of Physics, E.R.K. Arts and Science College, Erumiyampatti, Dharmapuri 636 905, Tamil Nadu, India c Department of Chemistry, IFET College of Engineering, Villupuram 605 108, Tamil Nadu, India d Department of Physics, University College of Engineering, Dindigul 624 622, Tamil Nadu, India e Environmental Science and Engineering Laboratory, Department of Civil Engineering, Yeungnam University, Geongsan 38541, Republic of Korea A R T I C L E INFO Keywords: Co-doped SnO 2 NPs Brilliant green Photocatalysis ABSTRACT Suggested here are a simple chemical precipitation method in order to synthesize bare and various levels of Co doping samples. The harvested samples were tested for their structural, optical, morphological and photo- catalytic properties. The optical study shows a decline in the band gap of SnO 2 on 0.075 M of cobalt doping. The tuned band gap of SnO 2 on doping utilizes the visible light for the photodegradation of brilliant green (BG) and recommends the usage of the optimum level of Co-doped SnO 2 in environmental remediation applications. 1. Introduction The effuents released from the dye industries pose a major threat to the environment. To address this major issue, there is need for cost effective technique. The usage of a prompt catalyst is one of the avail- able techniques in order to degradation of organic pollutants [1–3]. The many metal oxide photocatalysts, SnO 2 is known to have high catalytic activity in the UV region. However, the natural source sunlight has 45 % visible light and 5 % UV light [4,5]. Therefore, to utilize visible radia- tion, the band gap of SnO 2 should be reduced. The transition metal ions doping on the electronic structures of semiconductor nanostructures has gained great attention for solar energy utilization [6]. Doping transition metals in metal oxides can generate new energy levels in the forbidden gap from the host material and result in band gap energy reduction, thereby increasing in the visible light absorption. In the present work, we have taken more efforts to reduce the band gap of SnO 2 by doping it with different concentrations (0.025–0.125 M) of cobalt ions. As a doping material, cobalt is well-known to hinder the growth of crystal- lites and make an important contribution to its optical properties. Since the ionic radius of Co 2+ (0.58 Å) is lower than Sn 4+ (0.69 Å), cobalt ions could well substitute the Sn 4+ ions in the tin oxide matrix, which can tailor the band gap of the host material [7]. Recently, several researchers have focused on improving the photocatalytic of SnO 2 . Furthermore, increasing in the removal effciency is due to metal ions doping [8]. Among these, the highest removal of organic dye is due to the cobalt doping sample as compared to the tin oxide sample [9]. The different cobalt doping concentrations of tin oxide they observed an enhanced removal of dye [10]. Furthermore, synthesized tin oxide shows the en- ergy gap is decreased with cobalt doping and they observed an enhanced removal of organic dye [11]. Asaithambi et al. [12] reported that Co doped SnO 2 successfully synthesized by simple co-precipitation method, and then, enhanced removal of brilliant green dye solution. In this paper, we have synthesized bare and various mole percentages of cobalt doped SnO 2 NPs and their products were characterized by XRD, DRS, PL, FT-IR, SEM with EDS and TEM techniques. Study on physico-chemical properties and photocatalytic effect toward to brilliant green under visible light radiation was evaluated. 2. Experimental procedure Chemicals such as tin (II) chloride dehydrate (SnCl 2 H 2 O), oxalic acid dehydrate (C 2 H 2 O 4 2H 2 O), cobalt (II) nitrate hexahydrate (Co (NO 3 ) 2 6H 2 O) and brilliant green (C 27 H 34 N 2 O 4 S) were purchased from merck chemicals. Various mole concentrations of 0.025–0.125 M Co-doped * Corresponding authors. E-mail addresses: ragupathymsc@gmail.com (S. Ragupathy), yhahn@ynu.ac.kr (Y.-H. Ahn). 1 These author contributed equally for this work. Contents lists available at ScienceDirect Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche https://doi.org/10.1016/j.inoche.2022.110031 Received 20 July 2022; Received in revised form 19 September 2022; Accepted 25 September 2022