Boosting Electrocatalytic Activity of Bimetallic CoNi‐MOF for OER and HER Through a Synergistic Bimetallic Approach
Satyanarayana K. Konavarapu, Giyong Kim, Kyuchul Shin, Sung Yeol Kim
Abstract
Abstract Due to the decreasing availability, reduced stability, and high cost of noble metal‐based catalysts, the search for stable, efficient, and inexpensive electrocatalysts is of significant importance. In this study, three new isostructural Co(II), Ni(II), and CoNi metal‐organic frameworks (MOFs) based on bis‐coordinating ligand 3‐pyridyl acrylic acid are explored as efficient electrocatalysts. The structure of CoNi‐MOF was further confirmed by various experimental techniques. The electrocatalytic activities toward the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) revealed that the bimetallic CoNi‐MOF demonstrated significantly greater activity towards OER and HER compared to its monometallic counterparts, Co‐MOF and Ni‐MOF. CoNi‐MOF requires 350 mV and 150 mV overpotential to achieve a current density of 10 mA cm −2 for OER and HER, respectively. Moreover, they exhibited excellent stability for 6 hours and 1000 OER cycles, demonstrating its superiority in these reactions. The significant enhancement in the performance of CoNi‐MOF is attributed to the bimetallic synergistic effects between the redox‐active metal centers Co 2+ and Ni 2+ , which increase the activity of the catalyst's surface, resulting in enhanced current density and reduced overpotential. The hydrogen bond between coordinated water molecules and un‐coordinated carboxylate is essential for the electrochemical stability of the materials.