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

Abstract

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 (CuMoO4) is synthesized via a simple hydrothermal route. Further, the crystalline nature of CuMoO4 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 CuMoO4 are determined via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques, as well as energy-dispersive X-ray (EDX) analyses. The CuMoO4 microspheres exhibit interconnected nanoflake-like structures, which can improve the active surface area and efficiency of CuMoO4. Furthermore, the active surface area of the CuMoO4 microspheres is calculated via the Brunauer–Emmett–Teller (BET) method. The obtained catalytic performance of CuMoO4 is compared with those of its basic metal oxides, such as MoO3 and CuO. The obtained overpotentials (η) for CuO, MoO3, IrO2, and CuMoO4 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 CuMoO4 electrode reveals that it can sustain the electrochemical activity for 12 h. © 2021 Elsevier B.V.