Synthesis of NiO nanoparticles loaded fly ash catalyst via microwave assisted solution combustion method and application in hydrogen peroxide decomposition

Abstract

An efficient nickel oxide nanoparticles loaded fly ash catalyst (NiFAk) has been synthesized via microwave assisted solution combustion synthesis (MWSCS) method by using urea as a fuel and nickel nitrate as oxidizer. 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 characteristics of the chemically activated fly ash (CFAk) 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 confirmed that the prepared catalyst (NiFAk) is nanocrystalline with crystallite size 6.4 nm. Catalytic performance of NiFAk 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 NiFAk catalyst has been found suitable, eco-friendly and efficient process.