Synthesis of NiO nanoparticles loaded fly ash catalyst via microwave assisted solution combustion method and application in hydrogen peroxide decomposition Renu Hada a , Deepti Goyal b , Vishwajeet Singh Yadav a , Nayma Siddiqui c , Ashu Rani d,⇑ a Department of Chemistry, Ganpat University, Kherva, Mahesana, Gujarat, India b Department of Applied Chemistry, Gautam Buddha University, Gautam Budh Nagar, UP, India c Department of Chemistry, Govt. Madhav Science P.G. College, Ujjain, MP, India d Department of Pure and Applied Chemistry, University of Kota, Kota, Rajasthan, India article info Article history: Received 18 December 2019 Received in revised form 20 January 2020 Accepted 23 January 2020 Available online xxxx Keywords: Fly ash Microwave Nickel oxide Solution combustion Thermal activation Chemical activation Reactive oxygen species Advanced oxidation process abstract An efficient nickel oxide nanoparticles loaded fly ash catalyst (NiFA k ) has been synthesized via microwave assisted solution combustion synthesis (MWSCS) method by using urea as a fuel and nickel nitrate as oxi- dizer. Fly ash was thermally and chemically activated prior to being used as support material for catalyst synthesis to intensify bonding and dispersion of NiO nanoparticles over fly ash surface. The surface char- acteristics of the chemically activated fly ash (CFA k ) indicated that after chemical activation of fly ash, loading of NiO increased due to increase in surface hydroxyl groups (–OH) and the formation of a new calcium silicate hydrate phase. Characterization studies were done using some analytical techniques viz. XRF, BET surface area, X-ray diffraction, FTIR, SEM and SEM-EDX. The X-ray diffraction pattern con- firmed that the prepared catalyst (NiFA k ) is nanocrystalline with crystallite size 6.4 nm. Catalytic perfor- mance of NiFA k catalyst was checked on decomposition reactions of hydrogen peroxide. The reaction parameters were optimized by varying some parameters like as pH, calcination temperature, nature of catalyst etc. Results indicated that microwave irradiation increases the nucleation of nickel oxide over fly ash surface responsible for uniform loading of nanosized NiO particles over fly ash surface. MWSCS using urea as fuel for the synthesis of NiFA k catalyst has been found suitable, eco-friendly and efficient process. Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Confer- ence on Advanced Materials and Nanotechnology. 1. Introduction Hydrogen peroxide is a powerful oxidizing agent. Owing to its high oxidative capability it plays an important role in various industrial applications such as in waste water treatment, health additives, fish tank aeration, water aeration, agricultural and horti- cultural industries etc. [1]. In addition, it is also used as disinfectant in advanced oxidation processes (AOPs) due to its ability to release reactive O 2 and OH radical which deactivate organic materials and microorganisms present in water [2]. AOPs are much more efficient and attractive processes than conventional treatment methods due to release of highly oxidizing hydroxyl free radicals. These free rad- icals can be obtained by using single oxidants or by a subset of chemical processes which includes primary oxidants such as ozone, hydrogen peroxide and oxygen and/or combinations of ozone, H 2 O 2 and UV radiation and a combination of H 2 O 2 with homogeneous catalyst viz., ferrous ions in Fenton’s reagent, TiO 2 etc. [3]. It is well documented in the literature that the catalysts of metal ion in aqueous state or in powder state becomes unstable, and release some secondary pollutants in water [4]. Therefore, attempts have been made to improve the catalytic decomposition of hydrogen peroxide by replacing homogeneous catalysts with heterogeneous ones. For this purpose several heterogeneous cata- lyst and catalyst support materials have been developed. Among various support materials, fly ash (FA) due to its high surface area, presence of silica and alumina, higher surface energy and more act- ing faces, and its inertness in many catalytic processes is being uti- lized as support material for loading of metal and metal oxides [5–11]. Many physical and chemical methods like CVD [12], PVD https://doi.org/10.1016/j.matpr.2020.01.411 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advanced Materials and Nanotechnology. ⇑ Corresponding author. E-mail address: ashugck@rediffmail.com (A. Rani). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: R. Hada, D. Goyal, V. Singh Yadav et al., Synthesis of NiO nanoparticles loaded fly ash catalyst via microwave assisted solution combustion method and application in hydrogen peroxide decomposition, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.411