Synthesis of CuO/g-C3N4 composites, and their application to voltammetric sensing of glucose and dopamine

The preparation of 3 kinds of carbonaceous nanocomposites by hydrothermal treatment and subsequent calcination described. The first comprises a nanomaterial of type CuO/g-C3N4, with g-C3N4 in mass fractions of 2, 5 and 7wt%, respectively. The second comprises CuO/porous carbon (5wt%), and the third comprises CuO/carbon spheres (5wt%). All of them were employed to modify a glassy carbon electrode (GCE) to obtain electrochemical sensors for glucose and dopamine. The GCE modified with CuO/g-C3N4 (5wt%) displays the highest electrocatalytic activity towards glucose and dopamine. Figures of merit for sensing glucose (in 0.1M NaOH solution) include a wide linear range (0.5M to 8.5mM), a detection limit of 0.150M, and a sensitivity of 0.274A M (-1) cm (-2) (at a working potential of 0.60V vs. Ag/AgCl). The respective data for dopamine (in pH7.0 solution) are linear ranges from 0.2-16.0M and 16.0-78.7M, a lower detection limit of 60nM, and an electrochemical sensitivity of 0.834 and 0.331A M (-1) cm (-2) (at a working potential of 0.22V vs. Ag/AgCl). The good performance of the modified GCE is attributed to the synergetic interactions between CuO and the appropriate fraction of g-C3N4, and the improvement of conductivity.