Hierarchical Cu₂O/NiFeCo layered double hydroxide nanoarrays on copper foam obtained by a self-sacrificial templated...

The design of highly active, economical and highly stable electrocatalysts for the oxygen evolution reaction (OER) is very important for realizing sustainable energy conversion. Herein, a Cu₂O/NiFeCo layered double hydroxide electrode on a copper foam (CF) with a nanoarray structure (Cu₂O/NiFeCo LDH/CF) is fabricated by using Cu(OH)₂ on CF (Cu(OH)₂/CF) as a self-sacrificial template. The prepared Cu₂O/NiFeCo LDH/CF has a unique hierarchical nanostructure, high electrochemical active area and excellent integration of Cu₂O and NiFeCo LDH, resulting in low overpotentials of 228 mV and 269 mV for current densities of 10 and 100 mA cm^-2 in 1 M KOH, respectively, as well as an ultrasmall Tafel slope of 40 mV dec^-1. In highly alkaline 6 M KOH, a overpotential of only 213 mV can deliver a current density of 100 mA cm^-2. Moreover, the assembled water hydrolysis device operates stably for 50 h without a significant change in the potential in the strong alkaline solution. This high-efficiency OER performance and long-term stability make Cu₂O/NiFeCo LDH/CF promising for practical applications.