Analytical and Bioanalytical Electrochemistry is an international scientific journal published online by the Center of Excellence in Electrochemistry at the University of Tehran, Tehran, Iran. The journal was published quarterly from 2009 to 2011, bimonthly from 2011 to 2018, and has been published in at least eight issues per year since 2018. Analytical and Bioanalytical Electrochemistry - 16 12 2024 12 31 Synergistically Enhanced Electrocatalytic Performance of Mn-Co-Ni Oxides/rGO Composite for Efficient Oxygen and Hydrogen Evolution Reactions 1109 1121 719416 10.22034/abec.2024.719416 EN Mehdi Mehrpooya School of Energy Engineering and Sustainable Resources, College of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran Hydrogen and Fuel Cell Laboratory, University of Tehran, Tehran, Iran Sina Hosseini School of Energy Engineering and Sustainable Resources, College of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran Hydrogen and Fuel Cell Laboratory, University of Tehran, Tehran, Iran Journal Article 2024 11 05 This study presents the development of a highly efficient NiCoMn@N,Co-rGO electrocatalyst designed to facilitate electrochemical water electrolysis, specifically addressing both the Oxygen Evolution and Hydrogen Evolution Reactions. This catalyst features a novel hybrid nanostructure comprising Co-Ni-Mn oxides integrated onto nitrogen- and cobalt-co-doped reduced graphene oxide (N,Co-rGO). The synthesis involved the improved Hummers’ method for graphene oxide preparation, followed by nitrogen and cobalt doping via calcination, and deposition of Co-Ni-Mn oxides through a solvothermal process. Physicochemical and electrochemical characterizations confirmed the successful formation of a mesoporous structure and efficient synergy between the metal oxides and graphene substrate. The NiCoMn@N,Co-rGO composite exhibits superior catalytic efficiency in facilitating the Oxygen Evolution Reaction in alkaline media, achieving a potential of 1.58 V at 10 mA/cm² (overpotential: 0.27 V), compared to 1.62 V (overpotential: 0.50 V) for NiCoMn oxide. For the Hydrogen Evolution Reaction, it achieves a potential of -0.50 V at -10 mA/cm² (overpotential: 0.49 V), similar to NiCoMn oxide. The improved efficiency is ascribed to the synergistic effects of nitrogen and cobalt doping in the reduced graphene oxide framework, improving conductivity, active site accessibility, and structural stability. These findings establish NiCoMn@N,Co-rGO as a more efficient electrocatalyst for OER. https://www.abechem.com/article_719416_0a0fd7f94c4f2bb4a7bb32764cb14671.pdf