Biogenic Synthesis of Morphological Controlled Co3O4 Using Phyllanthus emblica Fruit Extract for Improved Electrochemical OER Activity of Co3O4/MoS2

Developing high-performance electrocatalysts made from abundant elements is essential in order to reduce the overpotentials required for the electrocatalytic water splitting reaction. So, cobalt-based multifunctional materials are readily available conductive catalytic precursors that can reduce the overpotential and energy costs required for oxygen evolution reaction (OER). Here in, the Co3O4 nanostructure was synthesised by a simple chemical precipitation method using the Phyllanthus emblica fruit extract as a stabilising agent. The fruit extract contains bioactive compounds that can facilitate the conversion of cobalt precursors into Co3O4 nanostructure. The morphology and size of the Co3O4 nanostructure were controlled by adjusting the reaction conditions, such as adding different amounts of amla extract. High-surface-area materials are particularly promising candidates for driving the oxygen evolution reaction (OER) at low overpotentials in alkaline media. This is due to their large number of available active surface sites. Finally, we used it for electrochemical OER activity in 1 M KOH, and the Co3O4/MoS2 catalyst shows the lowest overpotential of 213 mV at a current density of 10 mA/cm(2) and the Tafel slope with respect to its constituents such as Co3O4 (405 mV), MoS2 (486 mV), IrO2 (354 mV), etc. The improved electrochemical OER activity of the Co3O4 /MoS2 compound can be attributed to several factors. First, the controlled morphology of the Co3O4 nanostructure provides a high surface area, which increases the exposure of active sites and enhances the catalytic performance. Secondly, integrating Co3O4 nanostructure into the MoS2 matrix creates a favorable interface for electron transfer, improving the charge transfer kinetics during the OER. Lastly, the unique electronic and structural properties of MoS2 combined with the catalytic properties of Co3O4 result in a synergistic effect that enhances the electrochemical performance.