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 degrees 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.

Automated summary

A series of morphology-controlled NiFeOOH nanosheets were directly synthesized through a one-step mild in-situ acid-etching hydrothermal process. The NiFeOOH nanosheets synthesized under 120 degrees C showed the optimal electrochemical performance for urea oxidation reaction, requiring only a small overpotential and exhibiting stable activity. The assembled urea electrolysis set using these nanosheets as bifunctional catalysts achieved a much lower potential than that of water splitting. This work provides a foundation for developing high-performance urea oxidation catalysts for hydrogen production and urea-rich sewage purification.