Synthesis and characterization of NiFe2O4 nanoparticles as reusable magnetic nanocatalyst for organic dyes catalytic reduction: Study of the counter anion effect

This work concerns the preparation of NiFe2O4 with different counter ions using co-precipitation method to control their crystallite size, the materials were used as catalysts for the photocatalytic reduction of Methylene blue and Orange G dyes. Different characterization methods such as XRD, XPS, FTIR, SEM/EDS, VSM, and Zeta potential were employed for more information on our materials. The obtained results show clearly that the nature of the counter ions influences significantly the phase purity and crystallite size of NiFe2O4 nanoparticles. To study the individual contribution of crystallite size and lattice strain Scherrer formula, Williamson-Hall, and size strain plot calculation methods were employed. The results showed also that the material containing the purest phase and finer size was the best catalyst for the reduction of both dyes; the “NFCP” catalyst allowed a complete conversion of MB and OG dyes in a reaction time of 8 min and 4 min respectively. A study of the reusability was carried out and the obtained results showed that the catalyst can be reused more and more without losing its efficiency even after 5 cycles thus, confirming its stability. The phase purity, crystallite size, the counter ions difference, and the synergy between metals and the surface charge were the key parameters affecting the catalytic property. [Display omitted] •NiFe2O4 catalysts were successfully synthesized by varying counter anions via facile coprecipitation method.•Compatibility between chloride and nitrate counter-ion resulting in best catalytic reduction activity and NPs-size.•The best nanocatalyst exhibited important saturation magnetization about 67.79 emu/g.•The designed nanocatalyst can be reused five cycles without the influence of its efficiency.