NiCoP/NF 1D/2D Biomimetic Architecture for Markedly Enhanced Overall Water Splitting

The construction of a well-defined metal-organic framework (MOF) precursor structure is essential to obtain highly efficient transition metal phosphide electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting. In this regard, we propose a novel strategy involving the in situ conversion of flake nickel-cobalt hydroxide into NiCo MOF with a unique biomimetic architecture (i. e. Venus flytrap-like morphology with dense 1D nanowires anchoring on 2D nanosheets), and further phosphating the precursor into NiCoP that possesses a similar, distinctive structure. Specifically, 1D nanowires afford effective electron transfer, while 2D nanosheets provide enhanced mechanical stability to the composite. The experimental results show that this material has an enormous amount of available active sites, accelerated charge/mass transfer, and a structural synergistic effect. As a result, the as-prepared NiCoP/nickel foam (NF) catalyst only requires overpotentials of 78 and 262 mV to reach a current density of 10 mA cm(-2) for the HER and OER in 1.0 M KOH, respectively. Furthermore, the application of NiCoP/NF as a bifunctional catalyst for the overall water splitting reaction yields current densities of 10 mA cm(-2) at 1.60 V. Therefore, this is an effective strategy for the development of next-generation electrocatalysts for solar-energy conversion.

Automated summary

Constructing a well-defined metal-organic framework (MOF) precursor structure is crucial for obtaining efficient transition metal phosphide electrocatalysts for hydrogen evolution and oxygen evolution reactions in water splitting. A novel strategy involving the conversion of flake nickel-cobalt hydroxide into NiCo MOF with a unique biomimetic architecture, followed by phosphating the precursor into NiCoP, has been proposed. The resulting material shows accelerated charge/mass transfer, abundant active sites, and structural synergistic effects, achieving high current densities for both HER and OER at low overpotentials.