Boosting Oxygen Evolution Reaction Performance on NiFe-Based Catalysts Through d-Orbital Hybridization

Anion-exchange membrane water electrolyzers（AEMWEs） for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant Ni Fe-based catalysts. By introducing a third metal into Ni Fe-based catalysts to construct asymmetrical M-Ni Fe units, the d-orbital and electronic structures can be adjusted, which is an important strategy to achieve sufficient oxygen evolution reaction（OER） performance in AEMWEs. Herein, the ternary NiFeM（M: La, Mo） catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work. Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen, resulting in enhanced adsorption strength of oxygen intermediates, and reduced rate-determining step energy barrier, which is responsible for the enhanced OER performance. More critically, the obtained Ni Fe La catalyst only requires 1.58 V to reach 1 A cm-2 in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.