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 (N(2)H(4)). 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 N(2)H(4) 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 μM and 370 μM to 2.2 mM with a relatively low detection limit of 0.1 μM (S/N = 3) and a response time of less than 3 s. Furthermore, the sensor showed outstanding sensitivity and reproducibility.