Coordination polymer and layered double hydroxide dual-precursors derived polymetallic phosphides confined in N-doped hierarchical porous carbon nanoflower as a highly efficient bifunctional electrocatalyst for overall water splitting.

Controllable construction of proficient electrocatalyst with 3D hierarchical architecture to achieve low cost and high efficient overall water splitting is of great significance to the sustainable development. Hereby, trimetallic phosphides confined in N-doped carbon nanoflowers (CoNiP/CoNiFeP@NCNFs) were fabricated using CoNi coordination polymer nanoflowers/CoNiFe layered double hydroxide (CoNi CPNFs/CoNiFe LDH) as precursors followed by phosphorization. Benefiting from the unique 3D hierarchical porous architecture, preeminent conductivity, high specific surface area, efficient mass/charge transfer and synergic effect of various transition metals, the well-designed CoNiP/CoNiFeP@NCNFs exhibit extraordinary electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. Particularly, this novel material can work as a bifunctional catalyst in an integrated water-splitting electrolyzer, which only requires a low voltage of 1.55 V to realize the current density of 10 mA cm-2 with admirable durability (at least 28 h). This work certified the foreground of composites assembled by 3D hierarchical porous carbon and polymetallic phosphides for overall water splitting. It also provided a novel proposal for the rational designing and constructing highly active electrocatalysts by using coordination polymer and LDH as dual-precursors.