Pt (1 1 1) quantum dot engineered Fe-MOF nanosheet arrays with porous core-shell as an electrocatalyst for efficient overall water splitting

The preparation of Pt quantum dots (Pt QDs) is an effective way that can solve the high cost problem by reducing the high dosage requirement of noble metal Pt. On the other hand, organic metal framework (MOF) can be used for the stabilization of metal nanoparticles with small size and uniform dispersion. Herein, we successfully synthesized a bifunctional electrocatalyst via a facile one-step hydrothermal treatment. Pt QDs cores are uniformly coated with Fe-MOF nanosheet arrays shell (Pt QDs @Fe-MOF) with a porous cuboids structure on Ni foam (NF). With the quantum size and core-shell structure, the self-assembled porous cuboids of Pt QDs @Fe-MOF exhibited perfect electrochemical performance for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting. Particularly, the electrocatalyst with ultralow content of Pt QDs (1.84 μg cm −2 ) only needed the overpotential of 33 mV and 191 mV to achieve 10 and 100 mA cm −2 in 1 M KOH, respectively. In addition, the Pt QDs @Fe-MOF/NF electrodes possessed remarkable activity and stability to deliver a current density of 10 mA cm −2 at 1.47 V for overall water splitting of at least 100 h.