Unique CoP Microflower Decorated with Phosphorous-Enriched PtP₂ onto Nickel Foam with Interfacial Electronic Interactions to Boost Alkaline Water-Splitting

The development of stable and efficient electrocatalysts for overall freshwater/seawater water-splitting has received significant attention. In this study, the fabrication and electrocatalytic properties of phosphorus-enriched PtP2 dispersed on CoP (PtP2/CoP) for HER and OER in both alkaline fresh/seawater media are described. Physical characterization and density functional theory calculations reveal that strong electronic interfacial interactions between PtP2 and CoP optimized the reaction kinetics by regulating the adsorption/desorption of intermediates and the cleavage of reactants. Additionally, operando electrochemical impedance spectroscopy reveals that PtP2/CoP significantly decreased phase angle with increasing applied potential compared with CoP, demonstrating that the construction of heterostructure provides a faster charge transfer on the surface and in the inner layer. Notably, the catalyst only requires overpotentials of 101 and 298 mV to achieve a benchmark of 100 mA cm(-2) in alkaline freshwater for HER and OER. Moreover, the prepared catalyst featured overpotentials of 108 and 330 mV in an alkaline seawater electrolyte. Furthermore, a stable and high-efficiency water electrolysis operation can be achieved using PtP2/CoP as both the anode and cathode (1.63 V@100 mA cm(-2)) coupled with satisfactory durability. This finding provides a deeper comprehension of the interaction of Pt-less compounds and matrix in electrocatalysis for bifunctional electrocatalysts.