Chemical Transformation Induced Core-Shell Ni₂P@Fe₂P Heterostructures toward Efficient Electrocatalytic Oxygen...

The oxygen evolution reaction (OER) is a crucial reaction in water splitting, metal-air batteries, and other electrochemical conversion technologies. Rationally designed catalysts with rich active sites and high intrinsic activity have been considered as a hopeful strategy to address the sluggish kinetics for OER. However, constructing such active sites in non-noble catalysts still faces grand challenges. To this end, we fabricate a Ni₂P@Fe₂P core-shell structure with outperforming performance toward OER via chemical transformation of rationally designed Ni-MOF hybrid nanosheets. Specifically, the Ni-MOF nanosheets and their supported Fe-based nanomaterials were in situ transformed into porous Ni₂P@Fe₂P core-shell nanosheets composed of Ni₂P and Fe₂P nanodomains in homogenous dispersion via a phosphorization process. When employed as the OER electrocatalyst, the Ni₂P@Fe₂P core-shell nanosheets exhibits excellent OER performance, with a low overpotential of 238/247 mV to drive 50/100 mA cm^-2, a small Tafel slope of 32.91 mV dec^-1, as well as outstanding durability, which could be mainly ascribed to the strong electronic interaction between Ni₂P and Fe₂P nanodomains stabilizing more Ni and Fe atoms with higher valence. These high-valence metal sites promote the generation of high-active Ni/FeOOH to enhance OER activity.