Efficient electrocatalytic overall water splitting of porous 3D CoPt₃/a-FCWO-NS heterostructures: Morphology modulation and interfacial engineering for the formation of crystalline-amorphous nanosheets

Achieving efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) simultaneously in the electrocatalytic water-splitting is essential to achieve a green hydrogen economy. However, a rational catalyst design still faces great challenges due to the slow kinetic limitations such as electron transfer at the electrode-electrolyte interface. Herein, a porous 3D CoPt3/a-FCWO-NS heterostructures was formed by morphology modulation and interfacial engineering. Notably, the catalyst requires only 1.51 V to achieve 10 mA cm-2 in 1 M KOH, and a commercial 1.5 V cell can drive the overall water-splitting with excellent stability. DFT combined with XPS results reveal the electron transfer between CoPt3 and FeCoW oxides. Due to the ensemble effect CoPt3 exhibits an electron deficient state moderating the slow kinetics of the OER process. Furthermore, the substrate FeCoW oxides modulates the D-band position of CoPt3, and the suitable adsorption energy for hydrogen-containing intermediates makes CoPt3/a-FCWO favorable for the HER process.