Enhancing OER and overall water splitting performance of amorphous NiFe LDH grown on Ni foam with the needle-like NiCoP transition layer

Abstract

The oxygen evolution reaction is more challenging than the hydrogen evolution reaction in overall water splitting, not only because the four-electron reaction is more complex but also because the oxidizing environment of the anode reaction is more destructive to the electrode material. Generally, such destruction results in the formation of an oxide film that hinders the transition of electrons and subsequently decelerates the succeeding reaction. This paper proposes a transition layer for self-supporting electrodes (NiFe LDH@NiCoP/NF) in which NiCoP grows between the NF and NiFe LDH. The implementation of NiCoP as a transition layer, showcasing excellent antioxidation capability and conductivity, effectively reduced overpotentials and consequently enhanced the catalytic performance. Benefiting from this transition layer, in a 1.0 M KOH, the NiFe LDH@NiCoP/NF catalyst exhibited outstanding OER and HER performance, requiring only 281 and 102 mV, respectively, to achieve 100 and 10 mA cm−2, and also exhibited a cell voltage for overall water splitting of 1.56 V at 10 mA cm−2.