Amorphous P‐CoO<sub>X</sub> Promotes the Formation of Hypervalent Ni Species in NiFe LDHs by Amorphous/Crystalline Interfaces for Excellent Catalytic Performance of Oxygen Evolution Reaction
Huimin Xu, Chen‐Jin Huang, Hong‐Rui Zhu, Zhijie Zhang, Ting‐Yu Shuai, Qi‐Ni Zhan, V. Yu. Fominski, Gao‐Ren Li
Abstract
Abstract Water electrolysis has become an attractive hydrogen production method. Oxygen evolution reaction (OER) is a bottleneck of water splitting as its four‐electron transfer procedure presents sluggish reaction kinetics. Designing composite catalysts with high performance for efficient OER still remains a huge challenge. Here, the P‐doped cobalt oxide/NiFe layered double hydroxides (P‐CoO X /NiFe LDHs) composite catalysts with amorphous/crystalline interfaces are successfully prepared for OER by hydrothermal‐electrodeposition combined method. The results of electrochemical characterizations, operando Raman spectra, and DFT theoretical calculations have demonstrated the electrons in the P‐CoO X /NiFe LDHs heterointerfaces are easily transferred from Ni 2+ to Co 3+ because that the amorphous configuration of P‐CoO X can well induce Ni‐O‐Co orbital coupling. The electron transfer of Ni 2+ to the surrounding Fe 3+ and Co 3+ will lead to the unoccupied e g orbitals of Ni 3+ that can promote water dissociation and accelerate * OOH migration to improve OER catalytic performance. The optimized P‐CoO X /NiFe LDHs exhibit superior catalytic performance for OER with a very low overpotential of 265 mV at 300 mA cm −2 and excellent long‐term stability of 500 h with almost no attenuation at 100 mA cm −2 . This work will provide a new method to design high‐performance NiFe LDHs‐based catalysts for OER.