Three-dimensional nanoflower-like structured self-supported electrode S-MnCr-NiFe/NF as an efficient bifunctional electrocatalyst for overall water splitting

Developing high-performance transition metal-based electrocatalysts remains a critical challenge in water electrolysis for green hydrogen production. Herein, a dual-pronged modification approach is proposed, aimed at fine-tuning the local electronic structure and optimizing the 3D morphology of NiFe-layered double hydroxide (NiFe-LDH). By coupling Mn/Cr co-doping with subsequent sulfurization on NF, a self-supported S-MnCr-NiFe/NF catalyst was successfully fabricated. In 1.0 M KOH, the as-prepared catalyst exhibits remarkable bifunctional electrocatalytic activity, with ultra-low overpotential values of 141 mV for hydrogen evolution reaction (HER) and 151 mV for oxygen evolution reaction (OER) at 10 mA cm −2 . Moreover, the S-MnCr-NiFe/NF catalyst retains excellent stability even after 2500 cyclic tests and 100 h of continuous operation. Furthermore, when S-MnCr-NiFe/NF catalysts are employed as a bifunctional electrode in a two-electrode water-splitting device, the assembled electrolyzer delivers 10 mA cm −2 at 1.42 V. This study demonstrates a scalable and cost-effective paradigm for designing high-efficiency transition metal-based catalysts, offering significant potential for industrial-scale green hydrogen production.