Amorphous NiFe phosphides supported on nanoarray-structured nitrogen-doped carbon paper for high-performance overall water splitting.

• Nanoarray-structured nitrogen-doped carbon paper was achieved via plasma treatment. • Amorphous NiFe-P nanoparticles were assembled on NCP by electrodeposition method. • The unique features endow NiFe-P/NCP electrode with superior catalytic performance. • The NiFe-P/NCP||NiFe-P/NCP couple shows a low voltage of 1.547 V at 10 mA cm–2. The exploration of high-performance and low-cost electrocatalysts for catalyzing both hydrogen and oxygen evolution reaction (HER and OER) at high current density is of vital significance for the commercialization of water splitting. Herein, amorphous NiFe phosphides are electrodeposited on 3D nanoarray-structured nitrogen-doped carbon paper (NCP) for direct use as a hybrid electrode toward overall water splitting. The as-prepared NiFe-P/NCP electrode requires only an overpotential of 0.226 and 0.125 V at 50 mA cm–2 for OER and HER, respectively. In addition, NiFe-P/NCP electrodes are further measured as a catalytic cathode and anode couple (NiFe-P/NCP||NiFe-P/NCP) for overall water splitting, exhibiting a low cell voltage of 1.547 to reach 10 mA cm–2 as well as a long-term durability. Our work reveals the significance of introducing well-designed substrate and bimetallic active species for enhanced electrochemical performance towards overall water splitting. Image, graphical abstract [ABSTRACT FROM AUTHOR]