Boosting the electrochemical water splitting efficiency of Copper Vanadium Oxide by Annealing method

Electrocatalytic water-splitting is one of the promising processes for producing hydrogen as a renewable and ecologically friendly fuel replacing fossil fuel. Achieving cost-efficient, stable, and active bifunctional electrocatalysts through water electrolysis is the highest challenge as the highest rate of hydrogen and oxygen production is desired. The role of copper vanadium oxide in different annealing conditions, as a possible electrocatalyst for water splitting was investigated in terms of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Structural and morphological characterizations were done by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The electrocatalytic efficiency and stability were assessed by linear sweep voltammetry (LSV) and chronoamperometry (CA). The LSV measurements show that the copper vanadium oxide catalyst with 700 °C annealing temperature exhibited overpotentials of 232 mV and 260 mV to attain a cathodic current density of 10 mAcm⁻² and anodic current density of 20 mAcm⁻², respectively. A Tafel slope of 68 mVdec⁻¹ was required for the HER and for OER a Tafel slope of 72 mVdec⁻¹ was needed. In addition, stability tests regarding CA yield very good stability of the material. The high annealing temperatures are important as they restructure crystal structures, increase the number of active sites, and thus improve electrical conductivity. Consequently, the overpotentials for OER and HER decrease due to enhanced electron transfer efficiency causing favorable interactions between electrocatalysts and reactants. The current research highlights the capability of the copper vanadium oxide catalyst for water water-splitting process which is cost-effective and efficient for renewable hydrogen production.