Newly, magnetic nanoparticles have extensively been used as alternative catalyst supports, in the view of their high surface area which results in high catalyst loading capacity, high dispersion, low toxicity, environmental preservation, distinguished stability, and suitable catalyst reusing. In the present study, the magnetite nanoparticles, NiFe2O4@Ag and NiFe2O4@Mo, were synthesized and characterized. The antimicrobial activities and catalytic properties of synthesized nanoparticles were tested afterwards. For synthetizing the nanoparticle NiFe2O4@Ag, silver ions were loaded onto the surface of the modified NiFe2O4 and reduced to silver crystal by adding NaBH4. The antibacterial effects of NiFe2O4@Ag were examined against two species of soil and plant related bacteria named Bacillus subtilis (gram positive) and Pseudomonas syringae (gram negative), respectively. The antifungal activity of this nanoparticle was evaluated against two species of plant pathogenic fungi called Alternaria solani and Fusarium oxysporum. Biological results indicated that the synthesized material has shown an excellent antibacterial and antifungal activity against all examined bacteria and fungi so that, their growth were completely inhibited 24 h after treatment with NiFe2O4@Ag. For the synthesis of a heterogeneous catalyst NiFe2O4@Mo, complex Mo(CO)6 was loaded onto the surface of the modified NiFe2O4 nanoparticle. This catalyst was found as an efficient catalyst for epoxidation of cis-cyclooctene and a wide variety of alkenes, including aromatic and aliphatic terminal ones using tert-butyl hydroperoxide as oxidant. This new heterogenized catalyst could easily be recovered by using a magnetic separator and reused four consecutive and loss only 13% of its catalytic activity.

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