Bifunctional Pt-doped FeCoNiMnCr high-entropy alloy supported on 3D graphene via ultrafast Joule heating for alkaline overall water splitting

Developing bifunctional electrocatalysts with high activity and durability is critical for efficient electrochemical water splitting. In this study, using three-dimensional graphene (3DG) as the scaffold, trace Pt-doped FeCoNiMnCr high-entropy alloy (HEA) nanoparticles (≈ 4.4 nm) were in situ dispersed and anchored onto the pore walls of 3DG via impregnation adsorption followed by ultrafast Joule heating. The porous 3DG scaffold provides adsorption and anchoring sites for the metal precursors, enabling a uniform nanoparticle distribution after ultrafast Joule heating. The resulting composite exhibited bifunctional hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity in both alkaline and alkaline NaCl electrolytes. In an alkaline NaCl electrolyte (1.0 M KOH + 0.5 M NaCl), the catalyst required overpotentials of only 82.4 mV for the HER and 256.1 mV for the OER to achieve a current density of 10 mA cm −2 . A symmetric two-electrode electrolyzer assembled with FeCoNiMnCr/Pt@3DG electrodes showed no significant performance degradation after 50 h of continuous operation at 100 mA cm −2 . Notably, this synthetic strategy offers a new approach to enhancing the electrocatalytic performance of nanostructured high-entropy materials. These results establish ultrafast Joule heating of precursors supported on 3DG as a viable route for preparing low-Pt multicomponent electrocatalysts.