Fabrication of hydrazine sensor based on silica-coated Fe2O3 magnetic nanoparticles prepared by a rapid microwave irradiation method

Abstract

A facile, efficient and rapid method for fabrication of silica-coated Fe2O3 magnetic nanoparticles (NPs) by a microwave (MW) irradiation method is reported. The homogeneous heating produced by the MW irradiation is the key to attaining the effective and uniform coating on Fe2O3 magnetic nanoparticles (NPs) in water-ethanol solution. HRTEM images confirmed the successful formation of uniform silica shells around the Fe2O3 NPs surface whereas FT-IR data show the structural differences between non-coated and silica-coated Fe2O3 NPs. These uniformly coated Fe2O3 NPs showed superior dispersibility than the bare Fe2O3 NPs as confirmed by the zeta potential measurements. For potential chemical sensor development, silica-coated Fe2O3 magnetic NPs were deposited onto a flat glassy carbon electrode (GCE, surface area, 0.0316 cm2) to give a sensor with a fast response against selective hydrazine in phosphate buffer phase. Hydrazine sensor also exhibits a good sensitivity with long-term stability and enhanced electrochemical performances. The calibration plot is linear (r2: 0.9911) over the 0.2 nM to 2.0 mM hydrazine concentration ranges. The sensitivity and detection limit are ∼12.658 μAmM−1cm−2 and 76.0 pM (signal-to-noise ratio, at a SNR of 3) respectively. It is also commenced a promising future sensitive sensor development using silica-coated Fe2O3 magnetic NPs by I-V method for the important applications of hazardous and carcinogenic compounds in environmental fields.