Directional electron transport and strong chloridion repulsion enabled by Hierarchical NiCo2O4/NiCoP heterojunction for efficient seawater oxidation

Optimizing the efficiencies of both electron transport and chloridion repulsion are highly desired for achieving high-performance oxygen evolution reaction (OER) electrocatalysts in seawater oxidation, but still remains a huge challenge. In this study, an efficient synthetic method is developed to successfully synthesize a novel heterogeneous hollow polyhedron nanocages (denoted as NiCo 2 O 4 /NiCoP) with directional electron transport and strong chloridion repulsion properties, which profits from its diverse work functions and anion electrostatic repulsion in heterojunction nanostructure, respectively. Accordingly, NiCo 2 O 4 /NiCoP exhibits superior OER activity in 1 M KOH (η = 325 mV@10 mA cm −2 ) and alkaline simulated seawater (η = 340 mV@10 mA cm −2 ), as well as outstanding long-term stability. Density functional theory calculations demonstrate that the construction of NiCo 2 O 4 /NiCoP heterojunction promotes the directional electron transport in the heterogeneous interface and enables strong chloridion repulsion in comparison with individual NiCo 2 O 4 and NiCoP, thus largely improving its OER performance in alkaline simulated seawater.