Carbon quantum dots/octahedral Cu2O nanocomposites for non-enzymatic glucose and hydrogen peroxide amperometric sensor

Non-enzymatic electrochemical sensors for the detection of glucose and hydrogen peroxide (H2O2) were designed based on novel nanostructure electrocatalyst of carbon quantum dots (CQDs)/octahedral cuprous oxide (Cu2O) nanocomposites. The CQDs/octahedral Cu2O nanocomposites has been smoothly by a facile method with ultrasonic treatment and the morphologies of the synthesized materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) with Energy dispersive X-ray spectroscopy (EDS) and powder X-ray diffraction measurements (XRD). Compared to octahedral Cu2O, the CQDs/octahedral Cu2O exhibited preferable electrocatalysis to the glucose oxidation and H2O2 reduction. Amperometric sensing of glucose was realized with a linear response range from 0.02 to 4.3 mM, a detection limit of 8.4 μM (S/N = 3). The interferents of ascorbic acid (AA), uric acid (UA), dopamine (DA) and sodium chloride (NaCl) was also detected using the CQDs/octahedral Cu2O modified electrode, the results showed good selectivity for glucose detection. Besides, the nonenzymatic sensor also has good performance to the electrocatalytic reduction of H2O2, with a linear response range from 5 μM to 5.3 mM and a detection limit of 2.8 μM (S/N = 3). The CQDs/octahedral Cu2O nanocomposites have good selectivity for the H2O2 detection with the AA, NaCl and UA.