Ali A. Ensafi, E. Heydari-Soureshjani, B. Rezaei,  

In this report, [PW11MO39]5−@Ru-reduced graphene oxides (rGO) (M: Co, Ni, and Cu) were fabricated using a simple and inexpensive method. Several versatile characterization techniques including spectroscopic and electrochemical methods were used to investigate the nanocomposite. The behavior of the electrocatalysts with respect to supercapacitor application and oxygen reduction reaction (ORR) were investigated in acetic acid solution (pH 4.8) and alkaline media, respectively using voltammetry, galvanostatic charge-discharge and chronoamperometry methods. Results showed that the [PW11MO39]5−@Ru-rGO (M: Co, Ni, and Cu) electrodes towards supercapacitor application have a high specific capacitance (705, 624 and 568 F g−1 for Cu, Co and Ni, respectively), highest energy density of 99.05 relating to power density of 294.93, highest power density of 2400 corresponding to energy density of 28.13 and long life cycling. The ORR on [PW11MO39]5−@Ru-rGO electrodes
followed a four-electron transfer reaction at low overpotential. The catalysts exhibited a good catalytic capacity, durability, favorable kinetics, and low price, which make them desirable in conformity to green chemistry requirements.