Ultrasonic-electrodeposition of hierarchical flower-like cobalt on petalage-like graphene hybrid microstructures for hydrazine sensing

A facile, one-pot ultrasonic electrochemical method to synthesize hierarchical cobalt (Co)-nanoflowers on petalage-like graphene (GE) was developed. The hybrid microstructures were successfully evaluated as a new material for highly sensitive determination of hydrazine (N2H4). Scanning electron microscopic measurements displayed that the synthesized Co-GE exhibited a related hierarchical structure of a petalage-like GE homogeneous distribution as a matrix for the growth of smooth nanosheets-assembled Co nanoflowers. Co-GE was confirmed by energy dispersive X-ray spectrograms. Electrochemical methods were adopted to characterize the sensing properties of Co-GE towards the electrocatalytic oxidation of N2H4 at 0.15 V in 0.1 M pH 7.0 sodium phosphate buffered saline. The sensor displayed a broad linearity of 0.25-370 mu M and 370 mu M to 2.2 mM with a relatively low detection limit of 0.1 mu M (S/N = 3) and a response time of less than 3 s. Furthermore, the sensor showed outstanding sensitivity and reproducibility.