Interfacial microenvironment modulation enhancing catalytic kinetics of bimetallic (oxy)hydroxide heterostructures for highly efficient oxygen evolution reaction

Water splitting is a promising hydrogen production technology limited by the slow kinetic oxygen evolution reaction (OER). The development of highly active and robust OER catalysts is in high demand. A series of three-dimensional (3D) self-supported FeOOH@Ni(OH)2 heterostructures supported on nickel foam are synthesized and used as efficient OER catalysts using a simple hydrothermal method. The benefits of the appropriate 3D nanoflower morphology, the large number of FeOOH nanosheets adhered on the nanoflower surface, the formation of heterogeneous interfaces, and the synergistic effect of Ni(OH)2 and FeOOH significantly improve the OER catalytic performance of the material. The optimal catalyst in 1 M KOH, alkaline artificial seawater (1 M KOH + 1 M NaCl), and alkaline nature seawater (1 M KOH + seawater) require only 285, 286, and 325 mV overpotential, respectively, to achieve 100 mA cm-2 current density and has robust stability. This study contributes to the rational design of interface-engineered heterostructures for seawater splitting by synthesizing high catalytic activity catalysts.