New copper nanocatalyst was prepared by coating Fe3O4 magnetic nanoparticles with tetraethyl orthosilicate (TEOS), followed by functionalization with 3-chloropropyl(trimethoxy)silane and 4H-1,2,4-triazol-4-amine and complexation with copper(II) chloride. The new catalyst was characterized by various spectroscopic methods and was successfully used in the synthesis of 1-aryl-1H-tetrazoles by reaction of aromatic amines with sodium azide and triethyl orthoformate under solvent-free conditions at 100°C.