Facile Synthesis of Transition Metals (Co-Ni) Gallates and their Electrochemical Applications

Abstract

This work created several catalysts using a solventless technique, removing the requirement for hazardous solvents. This highlights sustainability and green chemistry concepts. With an emphasis on their use in the oxygen evolution process (OER), the produced catalysts were methodically characterized to investigate their structural, morphological, and electrochemical characteristics. Electrochemical analysis determined the catalysts’ exceptional OER activity. The top-performing catalyst at a current density of 50 mA/cm2, displayed an exceptionally low overpotential of 300 mV, highlighting its great catalytic efficiency. A result of 96.42 mV/dec from the Tafel slope analysis indicated good reaction kinetics and effective charge transfer at the electrode contact. The catalysts’ large electrochemical active surface area of the catalysts was validated by capacitance measurements resulting from electrochemical double-layer capacitance. The greatest Cdl value, which reached 27.5 mF/cm2, indicated an excess of active sites for the OER process. The catalysts' exceptional performance was further verified by electrochemical impedance spectroscopy, which showed that the best-performing sample had a charge transfer resistance of just 23 Ω, indicating quick electron transfer during the catalytic process. This study emphasizes the solventless synthesis process as a successful and sustainable strategy for creating high-performance OER catalysts. The results offer insightful information on the connection between structural characteristics and electrochemical performance, opening the door for further advancements in sustainable energy technology.