Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-018-0268-6 Efect of Ni 2+ doping on chemocatalytic and supercapacitor performance of biosynthesized nanostructured CuO Lija Arun 1,2  · C. Karthikeyan 3  · Daizy Philip 4  · M. Sasikumar 5  · Elaiyappillai Elanthamilan 6  · Johnson Princy Merlin 6  · C. Unni 7 Received: 26 June 2018 / Accepted: 21 October 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract The synthesis of metal oxide nanostructured materials derived from plant extract embraces the futuristic design of an eco friendly system by reducing the hazardous toxic chemicals. In the present work, copper oxide nanoparticles (CuO NPs) and Ni 2+ doped (0.003, 0.006 and 0.009 M) CuO NPs were prepared by green method using Azadirachta indica (A. indica) leaf extract. The XRD pattern reveals that the synthesized CuO NPs exhibits monoclinic structure. Nanofower like morphology is observed in FESEM and TEM analysis. The oxidation states of Cu (2p), Ni (2p) and O (1s) have been identifed in XPS spectra. The weight loss and thermal efects were investigated in TG–DSC analysis. The green synthesized materials efectively degrade the hazardous water pollutants like methylene blue, methyl orange and eosin yellow. The pseudocapacitive properties of CuO and Ni doped CuO NPs have been investigated through cyclic voltammetry and galvanostatic charge–discharge (GCD) studies. The Ni doped (0.009 M) CuO NPs exhibited high specifc capacitance of 511 F/g at a current density of 1 A/g, and good reversibility with cycling ef- ciency of 88% after 3000 GCD cycles for S4 electrode, suggesting its use as promising electrode material in supercapacitors. 1 Introduction Electronic circuits, solar cells, photodiodes and all such electronic devices are inevitable tools of our day to day life which gradually started to control our existence. The exist- ence of life has become dependent on the functionalities of such electronic equipment. The increased energy con- sumption in manufacturing processes resulted in an increase of electrical and electronic waste and in turn depletion of natural elements such as gallium and indium that are scarce in nature and their availability is assessed to be for about 20 years. Present situation demands need to curtail the resource depletion and to control the electronic waste dis- posal, thus minimizing the environmental risks in order to ensure a healthy-future life. In view of achieving the goal, eco-friendly materials named “Green materials” are being introduced. Avoiding the use of the toxic solvents and keep- ing the organic precursors at low cost will ensure the avail- ability of green materials. The methodology of low cost processing procedure features bio-degradability in mild degraded conditions at the end of life cycle is adopted [1]. Among the energy storage devices, supercapacitors have drawn substantial attention owing to high power density, wide range of operation, long duration of life times, environmental friendliness and fast charge/discharge rate, thus placing them between batteries and conventional capacitors [2–10]. Cur- rently, the ruthenium oxide, nickel hydroxide, cobalt oxide and manganese oxide are the most frequently used electrode materials and huge theoretical capacitances materials, which are attributed to several oxidation states, providing excellent electrochemical Faradaic reactions [11–14]. Nevertheless, these electrodes still have some drawbacks such as high cost, harmful to the environment, low conductivity and structural * Lija Arun lijababu12@gmail.com 1 Department of ECE, St Thomas Institute for Science and Technology, Thiruvananthapuram, Kerala 695584, India 2 LBS Centre for Science and Technology, Thiruvananthapuram, Kerala 695033, India 3 KIRND Institute of Research and Development PVT LTD, Tiruchirappalli, Tamil Nadu 620 020, India 4 Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India 5 PG and Research Department of Physics, Bishop Heber College, Tiruchirappalli, Tamil Nadu 620 017, India 6 PG and Research Department of Chemistry, Bishop Heber College, Tiruchirappalli, Tamil Nadu 620 017, India 7 Department of Electronics and Communication, T.K.M. College of Engineering, Kollam 691 005, India