Ultrafast synthesis of Cu2O octahedrons inlaid in Ni foam for efficient alkaline water/seawater electrolysis

Development of bifunctional cost-effective and self-supporting electrocatalysts for high-performance water/seawater electrolysis are vital for emerging energy storage and conversion technologies. Herein, an ultrafast strategy is reported to synthesis homogeneous Cu2O octahedrons inlaid in Ni foam (oct_Cu2O-NF) via spontaneous replacement of Ni with Cu, followed by rapid oxidization of Cu in air. Benefiting from the high dispersion of uniform octahedral structure and strong interaction between Cu2O and Ni foam, oct_Cu2O-NF displayed a superior activity for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) as well as outstanding stability. After assembling oct_Cu2O-NF as bifunctional electrodes for alkaline seawater splitting, the electrolyzer exhibited a very small cell voltage of 1.71 V to reach 10 mA cm−2. This brand-new way of ultrafast synthesis for oct_Cu2O-NF experimentally confirms the feasibility of Cu-based nanomaterials for efficient water/seawater electrolysis.