Constructing Morphologically Tunable Copper Oxide-Based Nanomaterials on Cu Wire with/without the Deposition of Manganese Oxide as Bifunctional Materials for Glucose Sensing and Supercapacitors.

Morphologically tunable copper oxide-based nanomaterials on Cu wire have been synthesized through a one-step alkali-assisted surface oxidation process for non-enzymatic glucose sensing. Subsequently, copper oxide-based nanomaterials on Cu wire as a supporting matrix to deposit manganese oxide for the construction of heterostructured Mn-Cu bimetallic oxide architectures through spontaneous redox reaction in the KMnO4 solution for supercapacitors. Field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed that morphological and phase transformation from Cu(OH)2 to CuO occurred in copper oxide-based nanomaterials on Cu wire with different degrees of growth reaction. In non-enzymatic glucose sensing, morphologically tunable copper oxide-based nanomaterials owned the high tunability of electrocatalytically active sites and intrinsic catalytic activity to meet efficient glucose electrooxidation for obtaining promoted non-enzymatic glucose sensing performances (sensitivity of 2331 µA mM-1 cm-2 and the limit of detection of 0.02 mM). In the supercapacitor, heterostructured Mn-Cu bimetallic oxide-based nanomaterials delivered abundant redox-active sites and continuous conductive network to optimize the synergistic effect of Mn and Cu redox species for boosting the pseudo-capacitance performance (areal capacitance value of 79.4 mF cm-2 at 0.2 mA cm-2 current density and capacitance retention of 74.9% after 1000 cycles). It concluded that morphologically tunable copper oxide-based nanomaterials on Cu wire with/without deposition of manganese oxide could be good candidates for the future design of synergistic multifunctional materials in electrochemical techniques.

Extended Graphite Supported Flower-like MnO2 as Bifunctional Materials for Supercapacitors and Glucose Sensing.

A simple, efficient, and cost-effective extended graphite as a supporting platform further supported the MnO2 growth for the construction of hierarchical flower-like MnO2/extended graphite. MnO2/extended graphite exhibited an increase in sp2 carbon bonds in comparison with that of extended graphite. It can be expected to display better electrical conductivity and further promote electron/ion transport kinetics for boosting the electrochemical performance in supercapacitors and glucose sensing. In supercapacitors, MnO2/extended graphite delivered an areal capacitance value of 20.4 mF cm-2 at 0.25 mA cm-2 current densities and great cycling stability (capacitance retention of 83% after 1000 cycles). In glucose sensing, MnO2/extended graphite exhibited a good linear relationship in glucose concentration up to about 5 mM, sensitivity of 43 µA mM-1cm-2, and the limit of detection of 0.081 mM. It is further concluded that MnO2/extended graphite could be a good candidate for the future design of synergistic multifunctional materials in electrochemical techniques.