In-Site Grown NiFeOOH Nanosheets Foam Directly as Robust Electrocatalyst for Efficient Urea Oxidation Application.

In this work, a series of morphology controlled NiFeOOH nanosheets were directly developed through a one-step mild in-situ acid-etching hydrothermal process. Benefiting from the ultrathin interwoven geometric structure and most favorable electron transport structure, the NiFeOOH nanosheets synthesized under 120 ˚C (denoted as NiFe_120) exhibited the optimal electrochemical performance for urea oxidation reaction (UOR). An overpotential of merely 1.4 V was required to drive the current density of 100 mA cm-2, and the electrochemical activity remains no change even after 5000 cycles accelerated degradation test. Moreover, the assembled urea electrolysis set by using the NiFe_120 as bifunctional catalysts presented a reduced potential of 1.573 V at 10 mA cm-2, which was much lower than that of overall water splitting. We believe this work will lay a foundation for developing high-performance urea oxidation catalysts for the large-scale production of hydrogen and purification of urea-rich sewage.