We demonstrated a high-yield and easily reproducible synthesis of a highly active oxygen evolution reaction (OER) catalyst, "the core-oxidized amorphous cobalt phosphide nanostructures". The rational formation of such core-oxidized amorphous cobalt phosphide nanostructures was accomplished by homogenization, drying, and annealing of a cobalt(II) acetate and sodium hypophosphite mixture taken in the weight ratio of 1:10 in an open atmosphere. Electrocatalytic studies were carried out on the same mixture and in comparison with commercial catalysts, viz., CoO-Sigma, NiO-Sigma, and RuO-Sigma, have shown that our catalyst is superior to all three commercial catalysts in terms of having very low overpotential (287 mV at 10 mA cm), lower Tafel slope (0.070 V dec), good stability upon constant potential electrolysis, and accelerated degradation tests along with a significantly higher mass activity of 300 A g at an overpotential of 360 mV. The synergism between the amorphous CoP shell with the CoO core is attributed to the observed enhancement in the OER performance of our catalyst. Moreover, detailed literature has revealed that our catalyst is superior to most of the earlier reports.

Asymmetric supercapacitor is fabricated using reduced graphene oxide-polymer (RGO-PEDOT.PSS) and reduced graphenemanganese oxide (RGO-CNF-MnO 2 ) nanocomposites as negative and positive electrodes, respectively. Both the RGO-PEDOT.PSS and RGO-CNF-MnO 2 (GCM) nanocomposite electrode were studied systematically with three electrode and asymmetric device configuration. The cyclic voltammetry (CV) and galvanostatic charge-discharge (CD) studies revealed a maximum specific capacitance of 247 F/g at 1 A/g between À0.9 to 0.1 V (vs. SCE) for RGO-PEDOT.PSS electrode. While the GCM nanocomposite electrode showed 145 F/g at 1 A/g between À0.1 to 0.9 V (vs. SCE). The X-ray diffraction (XRD) studies of GCM positive electrode revealed the formation of crystalline Akhtenskite MnO 2 hexagonal structure and the XRD of RGO-PEDOT.PSS confirms the complete reduction of graphene oxide (GO). The microscopic images of GCM demonstrate the MnO 2 nanowhiskers growth over the carbon support. The fabricated asymmetric supercapacitor device showed a cell voltage of 1.8 V in 1 M Na 2 SO 4 electrolyte. The CD profile of RGO-PEDOT.PSS//RGO-CNF-MnO 2 shows the device capacitance of 47 F/g with a high energy density of 21 Wh/kg while the symmetric device shows 5 and 5.6 Wh/kg for negative and positive electrodes respectively. The high energy density and electrochemical stability of the prepared asymmetric device is promising for electrochemical energy storage in aqueous electrolyte.