Synergistic coupling of NiLa2O2(CO3) with MnO2/GO for durable and efficient water splitting in an alkaline condition

Abstract

Water electrolysis represents a promising route for clean energy production, driving the development of innovative non-precious electrocatalysts to enhance efficiency and kinetic rates. In this work, the NiLa₂O₂(CO₃)@MnO₂/GO (NLOC@MnO₂/GO) was prepared using a two-step approach involving pyrolysis and a hydrothermal process. The NLOC@MnO₂/GO electrocatalysts showed a lower overpotential of oxygen evolution reaction (OER) for 190 mV and hydrogen evolution reaction (HER) for 78 mV at the current density of 10 mA cm^-2. Moreover, it exhibited excellent electrocatalytic stability over 55 h at a high current density of 50 and -100 mA cm^-2. The NLOC@MnO₂/GO served as both electrode (cathode and anode) in a two-electrode water splitting device, delivering 10, 100, and 300 mA cm^-2 at 1.56, 1.66, and 1.72 V, respectively. The exceptional activity arises from the intertwined architecture: Ni provides tunable electronic states, MnO₂ introduces multi-electron redox centers, and GO scaffolds facilitate rapid ion/electron transport while preserving structural integrity. This study advances bifunctional electrocatalyst design and rare-earth engineering, integrating electronic modulation, active-site density, and mass transport in a single platform, while laying the foundation for future multi-functional, earth-abundant hybrid catalysts in clean energy applications.