A Green Solvent-Free Approach Synthesis for Rational Designing of a NiFe-Layered Double Hydroxide [NiFe-LDH] Electrocatalyst for Hydrogen Generation

Creating cost-effective, chemically stable electrocatalysts to improve the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remains a major challenge in electrocatalytic water splitting. We synthesized a highly efficient NiFe-layered double hydroxide (LDH) electrocatalyst using a solvent-free method. The formation of well-interconnected metal ions with nanospherical architectures created an extensive electrochemically active surface area enriched with catalytically active sites, demonstrating synergistic effects. Preserving the suitable stoichiometric ratio, such as Ni 6 Fe 4 LDH, was crucial in enhancing the catalytic performance for both the HER and OER. The optimal Ni 6 Fe 4 LDH ratio established overpotentials of 167 mV (112 mV dec –1 ) for the HER and 280 mV (116 mV dec –1 ) for the OER, attaining a 10 mA cm –2 current density in 1 M KOH. Moreover, Ni 6 Fe 4 LDH demonstrated impressive robustness, stable up to 90 h with a minor decrease of 4.1 and 4.6% in the current density for the HER and OER. Notably, in the bifunctional two-electrode arrangement of Ni 6 Fe 4 LDH/NF||Ni 6 Fe 4 LDH/NF, effective water electrolysis was accomplished, preserving a stable 10 mA cm –2 current density at a bias of 1.64 V for over 140 h, with a slight current loss of 3.9% of the current density.