An Interfacial Electron Transfer on Tetrahedral NiS2/NiSe2 Heterocages with Dual‐Phase Synergy for Efficiently Triggering the Oxygen Evolution Reaction

Abstract Tetrahedral NiS 2 /NiSe 2 heterocages with rich‐phase boundaries are synthesized through a simultaneous sulfuration/selenylation process using Ni‐based acetate hydroxide prisms as precursor. Such a nanocage‐like NiS 2 /NiSe 2 heterostructure can expose more active sites, accelerate the mass transport of the ions/gas, and optimize the interfacial electronic structure, which shows a significantly lower overpotential of 290 mV at 20 mA cm −2 than those of NiS/NiS 2 and NiSe 2 as counterparts. The experimental characterizations and theoretical density functional theory (DFT) calculations unveil that the interfacial electron transfer from NiSe 2 to NiS 2 at the heterointerface can modulate the electronic structure of NiS 2 /NiSe 2 , which further cooperates synergistically to change the Gibbs free energy of oxygen‐containing intermediates as the rate‐determining step (RDS) from 2.16 eV (NiSe 2 ) and 2.10 eV (NiS 2 ) to 1.86 eV (NiS 2 /NiSe 2 heterostructures) during the oxygen evolution reaction (OER) process. And as a result, tetrahedral NiS 2 /NiSe 2 heterocages with dual‐phase synergy efficiently trigger the OER process, and accelerate the OER kinetics. This work provides insights into the roles of the interfacial electron transfer in electrocatalysis, and can be an admirable strategy to modulate the electronic structure for developing highly active electrocatalysts.