Fabrication of hydrazine sensor based on silica-coated Fe2O3magnetic nanoparticles prepared by a rapid microwave irradiation method

Abstract

A facile, efficient and rapid method for fabrication of silica-coated Fe2O3magnetic 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 Fe2O3magnetic nanoparticles (NPs) in water-ethanol solution. HRTEM images confirmed the successful formation of uniform silica shells around the Fe2O3NPs surface whereas FT-IR data show the structural differences between non-coated and silica-coated Fe2O3NPs. These uniformly coated Fe2O3NPs showed superior dispersibility than the bare Fe2O3NPs as confirmed by the zeta potential measurements. For potential chemical sensor development, silica-coated Fe2O3magnetic 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−2and 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 Fe2O3magnetic NPs by I-V method for the important applications of hazardous and carcinogenic compounds in environmental fields.