15 nanoparticles were modified by 3-chloropropyltrimethoxysilane. Then, a Gadolinium (Gd) dithizone complex on CoFe2O4/ SBA-15 was synthesized by anchoring Gadolinium ions on the CoFe2O4/ SBA-15/dithizone composite. The prepared material was characterized using powder X-ray diffraction (XRD), field emission scanning electron microscopy/ energy dispersive X-ray spectroscopy (SEM/EDX), elemental mapping, vibrating-sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption–desorption isotherm. The CoFe2O4/ SBA-15/dithizone/Gd composite consists of a mesoporous structure with a surface area by BET and t-plot of 122.2 m2/ g and 86.28 m2/ g respectively, with a mean pore size of 5.37 nm, and pore volume of 0.164 cm3/ g. The CoFe2O4/ SBA-15/dithizone/ Gd composite was successfully applied as a powerful catalyst for green synthesis of 5-substituted 1H-tetrazoles in water. This catalyst was recovered and reused several times without a significant decrease in efficiency and stability. The catalyst could be fully recovered by an external magnetic field and it showed good reusability
