Metal–Organic Framework-Derived 2D NiCoP Nanoflakes from Layered Double Hydroxide Nanosheets for Efficient Electrocatalytic Water Splitting at High Current Densities

Abstract

Two-dimensional (2D) metal–organic framework (MOF)-derived NiCoP nanoflakes, denoted as NiCo(nf)-P, are prepared via in situ growth of MOF using NiCo layered double hydroxide (LDH) as a sacrificial template, followed by phosphorization. The nanoparticle-decorated 2D nanoflake morphology and the intrinsic porosity inherited from the MOF precursor render NiCo(nf)-P a highly efficient bifunctional electrocatalyst toward hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting. In 1.0 M KOH electrolyte solution, NiCo(nf)-P shows low overpotentials of 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 needs low cell voltages of 1.74/1.86/1.94 V to reach 100/500/1000 mA cm–2, with outstanding long-term stability over 30 h. The excellent catalytic performance of NiCo(nf)-P outperforms most of the NiCoP-based electrocatalysts reported so far, indicating its great potential for the overall water splitting application.