Interfacial FeOOH/CoO nanowires array improves electrocatalytic water splitting

Abstract Interface engineering has become an effective strategy to improve the electrocatalytic performance because of the strong coupling and synergistic effects between individual components. Herein, both interfacial FeOOH/CoO nanosheets (FeOOH/CoO-NSs) and nanowires array (FeOOH/CoO-NWs) were in situ constructed on nickel foam (NF) through a simple one-step hydrothermal approach. The rational selection of Fe(NO3)3·9H2O as a Fe source prevents the formation of nanosheet, and enables the generation of nanowire structure due to chemical affination. Benefiting from the synergistic interaction between FeOOH–CoO interface and the unique nanowires array structure, the resultant FeOOH/CoO-NWs/NF exhibits outstanding electrocatalytic activity towards both OER and HER. For the overall water splitting, the bifunctional FeOOH/CoO nanoneedle catalyst requires a cell voltage of only 1.61 ​V to achieve a current density of 10 ​mA ​cm−2, which is much lower than that required for IrO2||Pt/C (1.62 ​V). The present work provides a new horizon to design highly efficient water splitting catalysts through synergistic modulation of interface and micro-nano structures.