CuO Crystalline Modified Glassy Carbon Electrodes for Anodic Amperometric Determination of Hydrogen Peroxide

Abstract

As an alternative selection of electrocatalytic surface modifier, the electrochemically generated copper oxides is reinvestigated by using cyclic voltammetry (CV), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Interesting phenomena have been found, which indicate that the electrodeposition from the Cu 2＋ solution under cyclic voltammetric conditions can generate a transparent Cu(OH) 2 crystalline on the surface of glassy carbon electrodes, and this crystalline can be further transferred to a novel cubic opaque CuO crystalline of about 300 nm in size by second step of cyclic voltammetry in pH 12 NaOH solution. The final electrode (denoted as nano-CuO/GCE) can catalyze the oxidation (as well as the reduction) of H 2 O 2 in basic solutions. It shows pH dependent three-part catalytic mechanism in the range from pH 7 to pH 14. In 0.10 mol/L NaOH solution, the amperometric response at 0.15 V (vs. SCE) can give a current sensitivity as high as 139 mA/(mol•L -1 ) in the rage of 5.0×10 -7 -6.0×10 -4 mol/L with a lower detection limit (s/n＝3) of 2.5×10 -8 mol/L, and a current sensitivity of 78.4 mA/(mol•L -1 ) in the rage of 6.0×10 -4 -2.0×10 -3 mol/L. This electrode also has excellent reproducibility and stability. The mechanisms for the two steps of preparation and the catalytic reactions are proposed. The nano-CuO crystalline modified electrode may have more applications in the field of electrochemical sensing.

A Novel CuxO Nanoparticles@ZIF-8 Composite Derived from Core–Shell Metal–Organic Frameworks for Highly Selective Electrochemical Sensing of Hydrogen Peroxide

“…Upon the addition of H 2 O 2 to a 0.10 M NaOH solution, an obvious increase of oxidation current could be seen and it constantly increased with increasing H 2 O 2 concentration (Figure A), implying that the ZIF-8 shell did not affect the diffusion of H 2 O 2 . According to previous literatures, − the reaction mechanism could be thought as follows: first, Cu + (i.e., Cu 2 O) was converted to Cu 2+ (i.e., Cu­(OH) 2 , CuO), and then to Cu 3+ (i.e., CuOOH) by electrochemical oxidation in alkaline media. Subsequently, H 2 O 2 was oxidized by Cu 3+ (i.e., CuOOH), and Cu 2+ was regenerated.…”

Electrochemical fabrication of metallic nanostructured electrodes for electroanalytical applications

“…In several instances lower detection limits have been reported than those found at enzymatic sensors. 46,128,[137][138][139] Several successful examples of these non-enzymatic peroxide sensors have been demonstrated by Bolshakov et al 46 and Lupu et al, 128 who both reported a LOD of 1 nM for their PB films. The former utilised electrodeposited PB on Au microelectrodes, whilst the latter used a polystyrene-based physical templating method to co-deposit polypyrrole and PB.…”

“…Copper and copper oxides have also been studied for their ability to sense peroxide. Lin et al 139 electrodeposited Cu on a glassy carbon electrode, followed by an electrochemical oxidation procedure in 10 mM NaOH. This produced a CuO film which was found to possess a LOD towards peroxide of 25 nM.…”

Rapid nonenzymatic monitoring of glucose and fructose using a CuO/multiwalled carbon nanotube nanocomposite-modified glassy carbon electrode

“…There have been several efforts to detect carbohydrates using nanostructured CuO. In addition, other researchers have fabricated nanosensors containing CNTs and metals/metal oxides using various techniques [28][29][30][31][32].…”