Au/Ni₁₂P₅ core/shell single-crystal nanoparticles as oxygen evolution reaction catalyst

We have demonstrated the improved performance of oxygen evolution reactions (OER) using Au/nickel phosphide (Ni₁₂P₅) core/shell nanoparticles (NPs) under basic conditions. NPs with a Ni₁₂P₅ shell and a Au core, both of which have well-defined crystal structures, have been prepared using solution-based synthetic routes. Compared with pure Ni₁₂P₅ NPs and Au-Ni₁₂P₅ oligomer-like NPs, the core/shell crystalline structure with Au shows an improved OER activity. It affords a current density of 10 mA/cm² at a small overpotential of 0.34 V, in 1 M KOH aqueous solution at room temperature. This enhanced OER activity may relate to the strong structural and effective electronic coupling between the single-crystal core and the shell.