Triggering the intrinsic catalytic activity of electrodeposited CoNiFe LDH <i>via</i> Pt decoration for an efficient hydrogen evolution reaction

Hydrogen is widely recognized as a clean and sustainable energy carrier, and the development of efficient, durable electrocatalysts for the hydrogen evolution reaction (HER) remains a key challenge in realizing large-scale hydrogen production. In this study, we report a two-step synthesis of a platinum decorated CoNiFe layered double hydroxide (Pt@CNF) electrocatalyst, engineered to enhance HER performance. Field-emission scanning electron microscopy (FE-SEM) confirms the uniform distribution of Pt nanoparticles on CoNiFe LDH (CNF) nanosheets. The incorporation of Pt, possessing an optimal hydrogen adsorption energy, significantly reduces the overpotential from 215 mV (CNF) to 117 mV (Pt@CNF) at a current density of 10 mA cm^-2. The enhanced intrinsic activity of Pt@CNF is further evidenced by a substantial increase in turnover frequency (TOF) from 7.1 × 10^-3 s^-1 to 14.6 × 10^-3 s^-1. Additionally, Pt@CNF exhibits a larger electrochemical surface area (ECSA) and higher active ECSA (<i>A</i>_ECSA) compared to pristine CNF, reflecting the greater density of accessible catalytic sites. The synergy between Pt and the CNF matrix improves both charge transfer kinetics and catalytic durability, enabling Pt@CNF to deliver low overpotentials of 298, 370, and 441 mV at high current densities of 100, 200, and 400 mA cm^-2, respectively. These findings highlight the potential of Pt@CNF as a high-performance HER electrocatalyst for next-generation hydrogen production technologies.