Electrochemical and Photoelectrochemical Sensing of Dihydronicotinamide Adenine Dinucleotide and Glucose Based on Noncovalently Functionalized Reduced Graphene Oxide-Cadmium Sulfide Quantum Dots/Poly-Nile Blue Nanocomposite

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.