Mo,Fe-codoped metal phosphide nanosheets derived from Prussian blue analogues for efficient overall water splitting

Designing non-precious electrocatalysts with multiple active centers and durability toward overall water splitting is of great significance for storing renewable energy. This study reports a low-cost Mo, Fe codoped NiCoPx electrocatalysts derived from Co-Fe Prussian blue analogue and following phosphorization process. Benefitted from the optimized electronic configuration, hierarchical structure and abundant active sites, the Mo,Fe-NiCoPx/NF electrode has shown competitive oxygen evolution reaction (ƞ10 = 197 mV) and hydrogen evolution reaction performance (ƞ10 = 99 mV) when the current density is 10 mA cm-2 in 1 M KOH solution. Moreover, the integrated water splitting device assembled by Mo,Fe-NiCoPx/NF as both anode and cathode only needs a voltage of 1.545 V to reach 10 mA cm-2. Density functional theory results further confirm that the Mo, Fe codoped heterostructure can synergistically optimize the d-band center and Gibbs free energy during electrocatalytic processes, thus accelerating the kinetics of electrochemical water splitting. This work demonstrates the importance of rational combination of metal doping and interface engineering for advanced catalytic materials.