Glucose sensing behavior of cobalt doped ZnO nanoparticles synthesized by co-precipitation method

Pure and Zn_1−xCo_xO (x = 0.05, 0.10 and 0.15) nanoparticles were synthesized by co-precipitation method. Powder X-ray diffraction studies confirmed that pure and Co doped ZnO have a single phase nature with hexagonal wurtzite structure and Co²⁺ ions were successfully incorporated into the lattice position of Zn²⁺ ions in ZnO matrix. FTIR and EDS spectra results confirmed the incorporation of the dopants into the ZnO lattice structure. FESEM images showed the flower like morphology in ZnO and flowers are dispersed to grains in Co doped ZnO nanoparticles. The chemical composition of Zn_0.90Co_0.10O nanoparticles were confirmed by XPS. The XPS results clearly showed the existence of Co as a doping element into the ZnO crystalline lattice. Further, the synthesized Co doped ZnO nanoparticles have been used for electrochemical non-enzymatic glucose biosensing. The lowest detection limit of the proposed sensor was found to be 5 µM. The sensor selectively oxidizes glucose in the presence of other interfering compounds like l-dopa, ascorbic acid, hydrogen peroxide and uric acid.