Mn2+ Doped NiS (Mn x Ni1−x S: x = 0.0, 0.3 and 0.5) Nanocrystals: Structural, Morphological, Opto-magnetic and Photocatalytic Properties

Abstract

To reduce the synthesis time, energy consumption, low cost, Mn2+-doped NiS (MnxNi1−xS: x = 0.0, 0.3 and 0.5) nano-photocatalysts were successfully synthesized by a facile, one-pot, microwave combustion method (MCM) within 10 min. In this MCM route, microwave heating has produced such functional nano-photocatalysts within few minutes of time. Powder XRD, FT-IR, EDX and SAED results were confirmed the formation of well crystalline single phase of NiS nano-crystals. The as-prepared samples consist of agglomerated particles with nano-crystals like morphologies confirmed by HR-SEM and HR-TEM analysis. The optical band gap energy (Eg) was estimated from UV–Vis DRS and PL study. The value of Eg is increased with increasing Mn doping in MnxNi1−xS lattice, due to decrease of particle size. VSM results confirmed a weak ferromagnetic behavior of MnxNi1−xS nano-crystals and the values of magnetization (Ms) gradually increased with increasing the concentration of Mn2+ cations, due to the higher magnetic moment (5 μB) of Mn2+ ions replaced the lower magnetic moment (2 μB) of Ni2+ ions in NiS. The present study leads to enhance the photocatalytic activity of MnxNi1−xS samples, TiO2 catalyst was added. As expected, MnxNi1−xS nanoparticles sensitized TiO2 catalyst showed enhanced photocatalytic degradation (PCD) of 4-chlorophenol (4-CP) under visible light irradiation. The alteration of MnxNi1−xS–TiO2 nano-composite catalysts shows higher adsorption with synergistic effect and enhances the separation of photogenerated electron–hole pairs, important to higher PCD efficiency.