Laser-engineered Inconel 625 for enhanced oxygen evolution electrocatalysis

The oxygen evolution reaction (OER) is a major bottleneck in electrochemical water splitting due to its sluggish kinetics and high overpotentials. Here, we report a single-step laser surface engineering approach to convert commercial Inconel 625 alloy into an active OER electrocatalyst. Pulsed laser treatment generates a hierarchical, "cauliflower-like" nanostructure that significantly enhances the electrochemically active surface area. Electrochemical testing in 1 M KOH shows that the laser-treated surface achieves an overpotential of 270 mV at 10 mA cm −2 , corresponding to a 30 mV cathodic shift relative to the untreated alloy. During electrochemical activation, selective dissolution of Mo and Cr produces a Ni-rich surface that facilitates the formation of catalytically active γ-NiOOH species. Raman spectroscopy confirms γ-NiOOH formation with characteristic bands at 470 and 548 cm −1 , while the shoulders at 493 and 539 cm −1 suggest Fe incorporation into the oxyhydroxide structure. Under OER conditions, we also detect low-intensity bands in the spectral region between 800 and 1150 cm −1 , which we ascribe to Ni-OO - species stabilized by cations. The Tafel slope decreases from 59.9 mV dec −1 for pristine Inconel 625 to 39.2 mV dec −1 after laser-treatment and electrochemical conditioning. Identical location SEM technique is used to follow how the hierarchical structure of the laser-treated sample partly coalesce and locally flatten after the electrochemical treatment. These results demonstrate that laser surface engineering provides a scalable and effective strategy to transform robust industrial alloys into functional OER electrocatalysts, offering new avenues for cost-effective water-splitting technologies. • Single-step laser engineering offers high-surface-area OER catalyst. • OER onset shifts ∼30 mV cathodically after laser and electrochemical treatment. • Tafel slope improves from 59.9 to 39.2 mV dec −1 after full activation. • EDXS, XPS, ToF-SIMS confirmed selective Cr and Mo dissolution during activation. • Raman confirms γ-NiOOH and Fe incorporation into α-Ni(OH) 2 /γ-NiOOH phases.