Ultrathin amorphous nickel doped cobalt phosphates with highly ordered mesoporous structures as efficient electrocatalyst for oxygen evolution reaction

Herein, the facile preparation of ultrathin (≈3.8 nm in thickness) 2D cobalt phosphate (CoPi) nanoflakes through an oil‐phase method is reported. The obtained nanoflakes are composed of highly ordered mesoporous (≈3.74 nm in diameter) structure and exhibit an amorphous nature. Attractively, when doped with nickel, such 2D mesoporous Ni‐doped CoPi nanoflakes display decent electrocatalytic performances in terms of intrinsic activity, and low kinetic barrier toward the oxygen evolution reaction (OER). Particularly, the optimized 10 at% Ni‐doped CoPi nanoflakes (denoted as Ni10‐CoPi) deliver a low overpotential at 10 mA cm−2 (320 mV), small Tafel slope (44.5 mV dec−1), and high stability for OER in 1.0 m KOH solution, which is comparable to the state‐of‐the‐art RuO2 tested in the same condition (overpotential: 327 mV at 10 mA cm−2, Tafel slope: 73.7 mV dec−1). The robust framework coupled with good OER performance enables the 2D mesoporous Ni10‐CoPi nanoflakes to be a promising material for energy conversion applications.MOE (Min. of Education, S’pore)Accepted versio