Carbon nanotube supported platinum nanoparticles for the voltammetric sensing of hydrazine

Electrochemical sensing of hydrazine using a highly sensitive platform based on nanosized Pt (nPt) particles is described. The sensing platform is developed by the pre-organization of metal precursor on multiwalled carbon nanotubes (MCNT) modified conducting substrate and subsequent chemical reduction of the precursor in aqueous solution. The Pt nanoparticles are characterized by transmission electron microscope, X-ray diffraction (XRD), spectral and electrochemical measurements. The nPt on MCNT modified electrode has spherical shape with 5–10 nm size. XRD and selected area electron diffraction pattern reveal the existence of (1 1 1), (2 0 0) and (2 2 0) planes of face centered cubic structure. The electrocatalytic activity of nPt on the MCNT modified electrode toward oxidation of hydrazine is examined. The nPt on the MCNT modified electrode exhibit significantly high electrocatalytic activity with respect to the polycrystalline Pt electrode. The nanoparticle coverage on the electrode has strong influence on the electrocatalytic activity. Gradual negative shift in the oxidation peak potential and increase in the peak current are observed while increasing the particle coverage. The nanoparticle-based electrode is highly stable and sensitive and it can sense as low as 0.5 nM hydrazine sulfate at the potential of −0.35 V without any redox mediator. The co-existence of hydrazine derivative N,N-dimethylhydrazine does not interfere the electrochemical sensing of hydrazine.