Metal–Organic\nFramework-Derived 2D NiCoP Nanoflakes\nfrom Layered Double Hydroxide Nanosheets for Efficient Electrocatalytic\nWater Splitting at High Current Densities

Abstract

Two-dimensional (2D) metal–organic framework (MOF)-derived\nNiCoP nanoflakes, denoted as NiCo_(nf)-P, are prepared via\nin situ growth of MOF using NiCo layered double hydroxide (LDH) as\na sacrificial template, followed by phosphorization. The nanoparticle-decorated\n2D nanoflake morphology and the intrinsic porosity inherited from\nthe MOF precursor render NiCo_(nf)-P a highly efficient\nbifunctional electrocatalyst toward hydrogen evolution reaction (HER),\noxygen evolution reaction (OER), and overall water splitting. In 1.0\nM KOH electrolyte solution, NiCo_(nf)-P shows low overpotentials\nof 199/283/317 and 315/378/416 mV at 100/500/1000 mA cm^–2 for HER and OER, respectively. For overall water splitting, it only\nneeds low cell voltages of 1.74/1.86/1.94 V to reach 100/500/1000\nmA cm^–2, with outstanding long-term stability over\n30 h. The excellent catalytic performance of NiCo_(nf)-P\noutperforms most of the NiCoP-based electrocatalysts reported so far,\nindicating its great potential for the overall water splitting application.