Synthesis and characterization studies of facile CuO:La 2 O 3 nanomaterial and its role as electrode for overall energy storage and energy generation applications

The current study implements an environmental-friendly and sustainable methodology to fabricate CuO:La 2 O 3 -based electrode by using phyto-aqueous extract derived from the Amaranthus viridis plant leaves. CuO:La 2 O 3 was synthesized in several concentrations ranging from 2.5 to 10%. The synthesized nanoparticles revealed varied morphology for different concentrations with a varying crystalline size in the range of 18.2–43.44 nm. The lowest optical band gap energy of 3.25 eV was observed for 7.5% doped concentration. Taking advantage of its unique morphology and lower crystalline size, 7.5% CuO:La 2 O 3 was specifically selected to be utilized as an electrode material for subsequent investigations involving supercapacitor and water splitting studies. The supercapacitor behavior was studied using cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) techniques. The specific capacitance value of 879.6 F/g was obtained for the fabricated electrode. The water splitting studies revealed the better potential of fabricated electrocatalyst for oxygen evolution reaction with an overpotential value of 351 mV as compared to that of hydrogen evolution reaction where the overpotential value of 182 mV was observed. Moreover, the fabricated electrocatalyst showed excellent cyclic stability for more than 2000 cycles and up to 20 h. Nevertheless, comprehensive findings displayed CuO:La 2 O 3 as an efficient energy storage material as well as promising catalytic material for the water splitting studies. Graphical abstract