One-step unipolar pulse electrodeposition of nickel hexacyanoferrate/chitosan/carbon nanotubes film and its application in hydrogen peroxide sensor

Unipolar pulse waveforms consist of an applied anode potential during the on-period and an open-circuit potential during the off-period. Unipolar pulse electrodeposition (UPED) was used to fabricate nickel hexacyanoferrate/chitosan/carbon nanotubes (NiHCF/CS/CNTs) nanocomposite films with controllable structure on the electrode surface of a hydrogen peroxide (H2O2) sensor. One-step electrodeposition of NiHCF/CS/CNTs film with insoluble-structure NiHCF nanoparticles was performed, and the whole procedure took only several minutes. The morphology and the composition of the NiHCF/CS/CNTs film were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS). With the introduction of CNTs, the NiHCF/CS/CNTs system formed showed synergy between CNTs and NiHCF with a significant improvement of redox activity of NiHCF due to the excellent electron-transfer ability of CNTs. Electrochemical experiments revealed that the modified electrode allowed low potential (−0.2 V) detection of H2O2 and showed high electrocatalytic activity towards the reduction of H2O2. The linear range for the detection of H2O2 was 0.04–5.6 mM with a high sensitivity of 654 mA M−1 cm−2 and a rapid response (less than 2 s). The detection limit for H2O2 was as low as 2.8 × 10−7 M (S/N = 3).