Present study reports the electrochemical activity of Cu2O nanoparticles using potassium permanganate (KMnO4) as an electrolyte for the photo-production of charge. In fact, Cu2O is a promising electrode material used in high performance supercapacitors. KMnO4 is a versatile chemical compound with various applications. For instance, it is also used in the textile industry for dyeing fabrics. Manganese ions are considered harmful to the environment; Therefore, KMnO4 was used as Mn source in this study. Photo-electrochemical activity of Cu2O nanoparticles was determined by cyclic voltammetry, galvanostatic charge–discharge measurements and electrochemical impedance spectroscopy in 0.1 M NaOH and 5 ppm KMnO4 aqueous solution as an electrolyte, under dark and solar simulator illumination. At 10mV/s scan rate and for ~1mg of nanoparticles, the maximum specific capacitance was found to be Cs = 198mF/g for 0.1 M NaOH, 5 ppm KMnO4 and 138 mF/g for 0.1 M NaOH solutions respectively. The redox mechanism was also studied by photocatalysis of KMnO4 aqueous solution under a solar simulator. The removal efficiency of manganese using Cu2O nanoparticles as a photocatalyst was 80%. Adsorption and photocatalysis were carried out using 10 mg of Cu2O with 5 ppm and 20 ppm of KMnO4 solution. The crystal structure and morphology were investigated using XRD, TEM and SEM micrographs. The optical properties were investigated with Raman, FTIR, and UV-Vis spectroscopies. The optical properties using UV-Vis absorption spectroscopy indicate the conversion of MnO4- into MnO2 and finally into MnO after photocatalysis and adsorption within 300 min. This study demonstrates the potential applicability of Cu2O nanoparticles as a photocatalyst and KMnO4 as an electrolyte in a photo-electrochemical cell.