MOF-derived nitrogen-doped CoO@CoP arrays as bifunctional electrocatalysts for efficient overall water splitting

Abstract In order to keep up with the increasing demands of renewable energy technologies, it is urgent to develop highly efficient bifunctional electrocatalysts for overall water splitting, which could produce hydrogen and oxygen at the same time. Herein, we report a self-supported bead string-like nitrogen-doped CoO@CoP (N–CoO@CoP) arrays derived from MOF materials, serving as a bifunctional catalyst for overall water splitting. The unique 3D bead string-like arrays endow unimpeded electronic transport path, abundant bubble release channels and expose more active sites, which can easily achieve high current density in the electrocatalytic reaction process. The doped atom N coming from nitrogen-contained MOF can tune the electronic structure of CoP, which enhances the electrocatalytic performance further. The electrocatalysts display superb oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance with a small overpotential of 332 mV and 201 mV at the current density of 100 mA cm−2, respectively. Moreover, an alkaline electrolyzer employing the N–CoO@CoP as the cathode and anode exhibits a cell voltage of 1.79 V at the current density of 100 mA cm−2 as well as robust durability.