Rich exposed interface-delivered electrocatalyst of trimetallic phosphide porous nanocubes for high-efficiency overall water splitting

In this study, a hollow heterostructure derived from trimetallic NiCoFe phosphide nanocubes (NCF NCs) loading platinum (Pt–NCFP NCs) is designed by a facile synthetic approach (co-precipitation–dip cast–phosphidization) for seeking an excellent electrocatalyst to obtain high-performance water electrolysis. The synergistic effects derived from Pt and porous NCFP nanocubes promote superior electrical conductivity and catalytic active sites to boost both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics. The as-developed Pt–NCFP NCs material shows an overpotential of 100 mV for HER and 250 mV for OER to reach a current response of 10 mA cm⁻². Interestingly, the two-electrode electrolyzer cell based on a couple of Pt–NCFP NCs_(+/−) delivers a small cell voltage of 1.56 V at 10 mA·cm⁻² in 1.0 M KOH at 70 °C and favorable stability. This work suggests a way to design next-generation electrocatalysts for high-efficiency hydrogen generation, while also demonstrating that Pt–doping could be a feasible approach to improve the HER and OER performance of Prussian blue analog (PBA)-based nanocubes.