Reduced graphene oxide‐CdS quantum dots (rGO‐CdS QDs) nanocomposite was synthesized with a one‐pot and facile solvothermal strategy and characterized with X‐ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. The nanocomposite modified with electropolymerized Nile blue (NB) had high electrocatalytic and photoelectrocatalytic activity toward NADH oxidation with lowering 700 mV of overvoltage compared to bare GCE. The linear response up to 200 µM was obtained for photoamperometric determination of NADH and the detection limit was 1 µM (S/N=3). Furthermore, with covalence immobilizing of glucose dehydrogenase onto the nanocomposite, the electrochemical and photoelectrochemical ability of the proposed system toward glucose biosensing was also investigated.

Here, a simple one‐step solvothermal procedure was employed to synthesize a nanocomposite containing graphene‐nanosheets and CdS quantum dots (GNs‐CdS QDs). The electrochemical oxidation of chlorpromazine (CPZ) to chlorpromazine‐sulfoxide (CPZ‐SO) onto a GNs‐CdS QDs/ionic liquid (IL) nanocomposite modified glassy carbon (GC) electrode give rise to redox‐active products which showed excellent electrocatalytic and photoelectrocatalytic activity toward NADH oxidation at reduced overpotential. A linear response up to 200 µM was obtained for photoamperometric determination of NADH with detection limit 1 µM. Immobilizing alcohol dehydrogenase(ADH) onto the modified electrode via a simple cross linking procedure, the photoelectrochemical capability of the proposed system toward ethanol biosensing was clearly shown.

The electrochemical conditioning of amino-carbon nanotubes (CNTs) on a graphene support in an alkaline solution is used to produce -NHOH as hydrophilic functional groups for the efficient immobilization of bilirubin oxidase enzyme. The application of the immobilized enzyme for the direct electrocatalytic reduction of O2 is investigated. The onset potential of 0.81 V versus NHE and peak current density of 2.3 mA cm(-2) for rotating modified electrode at 1250 rpm, indicate improved biocatalytic activity of the proposed system for O2 reduction.