Chemical synthesis of a microsphere-like copper molybdate electrode for oxygen evolution reaction

The sluggish mechanism of oxygen evolution reaction (OER) inhibits the efficiencies of different energy storage systems. Thus, recent studies have mainly focused on designing highly active electrocatalysts to enhance OER. Here, a porous microsphere-like copper molybdate (CuMoO 4 ) is synthesized via a simple hydrothermal route. Further, the crystalline nature of CuMoO 4 is confirmed via X-ray diffraction (XRD). The chemical states of the designed sample are determined via X-ray photoelectron spectroscopy (XPS). The morphology and elemental composition of CuMoO 4 are determined via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques, as well as energy-dispersive X-ray (EDX) analyses. The CuMoO 4 microspheres exhibit interconnected nanoflake-like structures, which can improve the active surface area and efficiency of CuMoO 4 . Furthermore, the active surface area of the CuMoO 4 microspheres is calculated via the Brunauer–Emmett–Teller (BET) method. The obtained catalytic performance of CuMoO 4 is compared with those of its basic metal oxides, such as MoO 3 and CuO. The obtained overpotentials ( η ) for CuO, MoO 3 , IrO 2 , and CuMoO 4 were 286, 294, 267, and 247 mV with Tafel slope values of 65, 84, 58, and 53 mV/dec, respectively. The study for long-term stability of the CuMoO 4 electrode reveals that it can sustain the electrochemical activity for 12 h.