Facile synthesis of nickel oxide thin films from PVP encapsulated nickel sulfide thin films: an efficient material for electrochemical sensing of glucose, hydrogen peroxide and photodegradation of dye

Nickel oxide thin films were grown on ITO (indium tin oxide) substrates by two-step processes: (i) electrodeposition of polymer encapsulated nickel sulfide (PVP-NiS) thin films and (ii) thermal air oxidation of the as-deposited PVP-NiS thin films at 350 degrees C. A drastic morphological change occurred due to the phase transformation. The cyclic voltammetry study shows that the ITO/NiO electrode facilitates the oxidation of glucose along with an excellent reactivity towards its sensing. The CV study also reveals that the material is effective as an electrode material for the reduction of hydrogen peroxide (H2O2). The amperometric study shows that the electrode has an ultrasensitive current response (1013.76 mu A mM(-1)) with a detection limit of 4.6 mu M (signal to noise ratio (S/N) = 3) for glucose and a sensitivity of 82.73 mu A mM(-1) with a detection limit of 5.2 mu mM was observed for H2O2. In addition, excellent selectivity and stability have been observed for both cases. The sensor was tested in a wide range concentration of glucose and peroxide and a linear response was observed. Low detection limit, high sensitivity as well as ease of fabrication are some of the advantages of the proposed ITO/NiO sensor. The material also shows a high photocatalytic activity toward dye degradation. The morphological advantage, i.e. spherical porous nanograins, allows a more efficient transport of the reactant molecules to the active interfaces and results in a strong photocatalytic activity to degrade methyl orange (MO) dye.