Pseudocapacitance behavior of copper and nickel co-doped zinc oxide nanoparticles with enhanced photocatalytic performance

In this study, pure zinc oxide (ZnO) and Zn 0.98− x Cu 0.02 Ni x O (where x = 0.01, 0.03, 0.06) nanoparticles (NPs) were synthesized through the method of chemical co-precipitation. The TG-DTA, XRD, FT-IR, SEM, HR-TEM, UV–Visible DRS, XPS, Photocatalysis, and CV analysis were used to examine pure ZnO and Cu–Ni co-doped ZnO NPs. The thermal stability of synthesized NPs is confirmed by TG- DTA. The XRD verifies that hexagonal wurtzite has a decreasing crystallite size and an inverse relationship with an increasing optical band gap. The surface morphology shows the formation of well-defined nano-spherical shapes. The HR-TEM analysis determines that the particle size decreases with co-doping Cu and Ni to ZnO NPs. The photocatalytic activity was carried out using methylene blue dye under solar irradiation. The photodegradation efficiency of pure ZnO NPs improved when Cu and Ni were co-doped in ZnO NPs. The electrochemical analysis reveals the excellent specific capacitance of 596.43 F/g at a 10 mV/s scan rate for the Zn 0.92 Cu 0.02 Ni 0.06 O electrode. The GCD analysis finds that the Zn 0.92 Cu 0.02 Ni 0.06 O electrode has 0.35 kW/kg power density and 128.76 Wh/kg energy density. The experimental findings show that incorporating Cu and Ni in the ZnO matrix boosts photocatalytic activity and electrochemical performance. So, the synthesized NPs are considered potential materials for wastewater treatment and supercapacitor applications.